Purging system and method for zinc-nickel flow battery

Abstract

The invention discloses a zinc-nickel flow battery purging system and method. The purging system comprises a purging gas supply module, a flow control module, a purging pipeline network, a pressure monitoring module, a gas collection module and an intelligent control system, the purge gas supply module is connected with the flow control module, the flow control module is connected with the purge pipeline network, the purge pipeline network is connected with the zinc-nickel flow battery stack, and the zinc-nickel flow battery stack is connected with the gas collection module. The purging gas supply module, the flow control module, the pressure monitoring module and the gas collection module are all connected with the intelligent control system; and a pressure monitoring module is arranged on the purging pipeline network. The purging system disclosed by the invention can effectively control the content of oxygen and hydrogen in the battery, reduce impurity deposition and gas accumulation on the surface of an electrode, prevent potential safety hazards caused by gas accumulation, reduce explosion risk and internal resistance of the battery, improve charge-discharge efficiency of the battery, improve safety and prolong the service life of an electrolyte and the electrode.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid flow batteries, and in particular relates to a purge system and method for zinc-nickel liquid flow batteries. Background Art

[0002] Zinc-nickel flow battery (Zn-Ni Flow Battery) is an important branch of the flow battery field. Due to its high energy density (high theoretical capacity of zinc), low cost (abundant zinc and nickel resources), and environmental friendliness, it is regarded as a potential candidate for large-scale energy storage technology. In recent years, with the rapid development of renewable energy (such as wind power and photovoltaics), the demand for long-term energy storage technology has surged. Flow batteries have attracted much attention due to their power and capacity decoupling design and long cycle life. Zinc-based flow batteries (such as zinc-bromine, zinc-iron, and zinc-nickel systems) have become a research hotspot due to their high energy density, but the zinc-nickel system faces the following key challenges in the commercialization process:

[0003] Zinc negative electrode oxidation problem: Zinc easily reacts with oxygen in the electrolyte to form zinc oxide (ZnO), resulting in loss of active materials and battery capacity decay.

[0004] Nickel positive electrode stability issues: Nickel-based oxides (such as NiOOH) are prone to structural collapse or side reactions at high potentials, and the presence of oxygen will exacerbate this process.

[0005] Side reactions in water electrolysis: When overcharged or the local current density is too high, the water in the electrolyte is decomposed into hydrogen and oxygen, which not only reduces energy efficiency but also leads to changes in the pH value of the electrolyte and the risk of gas accumulation.

[0006] Safety risks: Hydrogen may cause explosions in a closed environment, requiring efficient gas management.

[0007] Currently, the industry mainly alleviates the above problems through electrolyte optimization (additives, pH control), electrode material modification (porous structure, catalyst coating) and battery structure design (bipolar plate flow channel optimization), but the active management technology after gas precipitation is still relatively weak. Traditional methods rely on mechanical seals or catalyst-assisted compounding (such as Pt catalysts promoting H2 / O2 compounding into water), but there are problems such as high cost, low efficiency or dependence on additional energy. Therefore, the development of an efficient and low-cost gas purge system has become a key technical requirement for the practical application of zinc-nickel liquid flow batteries.

[0008] 2) Explanation of relevant key technologies

[0009] (1) Inhibition of the reaction between zinc anode and oxygen

[0010] Zinc deposition / dissolution mechanism: Zinc is deposited as Zn during the charge and discharge process. 2+The oxygen intrusion directly reacts with zinc to form ZnO (an irreversible side reaction), resulting in loss of active material.

[0011] Dendrite growth problem: Uneven zinc deposition can easily form dendrites, which can pierce the diaphragm and cause a short circuit, and oxygen can accelerate this process.

[0012] Existing solutions:

[0013] Electrolyte additives (such as Bi 3 +、Pb 2 +) regulating the zinc deposition morphology;

[0014] Porous electrode design (such as carbon felt, zinc foam) increases the reaction area and reduces the local current density;

[0015] Modified membranes (such as Nafion membranes) block oxygen diffusion.

[0016] (2) Improved stability of nickel cathode

[0017] Nickel oxide cycling reversibility: Nickel cathodes convert to high-valent NiOOH during charging and are reduced to Ni(OH)2 during discharge. The presence of oxygen may cause NiOOH to overoxidize to form unstable products (such as NiO2), reducing cycle life.

[0018] Catalyst requirements: Nickel cathode reaction kinetics are slow, and usually requires loading of catalysts (such as Co and Mn oxides) to improve efficiency.

[0019] (4) Gas Emission and Safety Management

[0020] Conditions for water electrolysis side reactions: When the battery operating voltage exceeds the decomposition voltage of water (about 1.23V, a higher voltage is actually required due to overpotential), 2H2O→2H2↑+O2↑ occurs.

[0021] Traditional gas management technology:

[0022] Catalytic recombination: using precious metal catalysts to promote the recombination of H2 and O2 into water, but this requires additional energy consumption and the catalyst is easily poisoned;

[0023] Gas absorbing materials: such as vanadium electrolyte absorbs oxygen, but the compatibility is poor;

[0024] Passive exhaust: Gas is released slowly through a breathable membrane, but electrolyte loss due to evaporation cannot be avoided.

[0025] If a simple purge system is used, problems such as incomplete purge and high energy consumption will occur, which cannot effectively meet the needs of zinc-nickel flow batteries. Therefore, there is an urgent need for a more efficient, reliable, and intelligent purge system and method that adapts to the characteristics of zinc-nickel flow batteries. This system can intelligently purge based on the real-time status of the battery, improve purge efficiency, and reduce energy consumption. Summary of the Invention

[0026] To address the problems of zinc negative electrode oxidation, reduced nickel positive electrode stability, and changes in the electrolyte environment caused by oxygen intrusion during battery operation, the present invention aims to provide a zinc-nickel liquid flow battery purge system and method. The system achieves efficient and safe purge of the interior of the zinc-nickel liquid flow battery, thereby improving battery performance and service life.

[0027] To achieve the above object, the technical solution adopted by the present invention is:

[0028] An intelligent purge system for zinc-nickel flow batteries, comprising a purge gas supply module, a flow control module, a purge pipeline network, a pressure monitoring module, a gas collection module and an intelligent control system;

[0029] Among them, the purge gas supply module is connected to the flow control module, the flow control module is connected to the purge pipeline network, the purge pipeline network is connected to the zinc-nickel liquid flow battery stack, the zinc-nickel liquid flow battery stack is connected to the gas collection module, the purge gas supply module, the flow control module, the pressure monitoring module and the gas collection module are all connected to the intelligent control system; a pressure monitoring module is set on the purge pipeline network.

[0030] Furthermore, the purge gas supply module includes an air storage tank, an air compressor, a filter drying system, a nitrogen preparation machine and a nitrogen storage tank;

[0031] Among them, the air storage tank is connected to the air compressor, the air compressor is connected to the filter drying system, the filter drying system is connected to the nitrogen preparation machine, and the nitrogen preparation machine is connected to the nitrogen storage tank.

[0032] Furthermore, the flow control module includes a connected mass flow meter and a flow control valve. Based on the PID closed-loop control algorithm, the gas flow is fed back in real time through the mass flow meter to adjust the opening of the flow control valve so that the deviation of the purge gas flow from the set value is ≤±2%.

[0033] Furthermore, the intelligent control system is used to update the control instructions according to the gas evolution signal of the battery, and then perform pressure compensation correction, output the adjusted flow, and determine whether it is stationary. If it is stationary, switch to 30% flow mode. If it is not stationary, collect the flow signal, calculate the deviation through PID, if the deviation is greater than 2%, increase the valve opening, and if the deviation is ≤-2%, reduce the valve opening.

[0034] Furthermore, the purge pipe network includes multi-stage branch purge pipes, which are equipped with gas flow regulating valves and pressure monitoring modules. One end of the purge pipe is connected to the flow control module, and the other end extends to the interior of each battery cell of the zinc-nickel liquid flow battery.

[0035] Furthermore, the multi-stage branch purge pipeline includes a first main pipeline, several branch pipelines and a second main pipeline. The inlet of the first main pipeline is connected to the flow control module, the outlet of the first main pipeline is connected to the inlet of each branch pipeline, the outlet of each branch pipeline is connected to the inlet of a battery cell of the zinc-nickel liquid flow battery through a one-way valve, and the outlet of each battery cell is connected to the inlet of the second main pipeline through a branch pipeline.

[0036] Furthermore, the pressure monitoring module includes a connected pressure sensor and a pressure display instrument. The pressure sensor converts the detected pressure signal into an electrical signal and transmits it to the pressure display instrument.

[0037] Furthermore, a gas collection module is provided inside the battery cell of the zinc-nickel flow battery. The battery internal gas collection module includes a collection pipe and a collection container. One end of the collection pipe is connected to the interior of the battery cell, and the other end is connected to the collection container. A filtering device is provided inside the collection container.

[0038] The gas collection module also includes a nitrogen recovery loop, which includes a nitrogen recovery compressor connected to the purge gas supply module.

[0039] Furthermore, the collection container includes a gas-liquid separation tank, which includes a cyclone separator, a precision filter element and an activated carbon adsorption layer. The cyclone separator is connected to the precision filter element, and the precision filter element is connected to the activated carbon adsorption layer.

[0040] A zinc-nickel flow battery intelligent purging method comprising:

[0041] Before the purge begins, obtain the real-time status parameters of the battery, including voltage, current, temperature and electrolyte concentration;

[0042] According to the real-time status parameters of the battery, combined with the preset purge strategy (after obtaining the start signal, the purge system starts and begins to purge (preset 10 minutes). Once the electrochemical sensor detects that the oxygen content is less than 0.1%, the purge stops), set the purge parameters, including gas type, flow rate and pressure;

[0043] The purge gas supply module provides the corresponding purge gas according to the set purge parameters, and ensures the stability of gas flow and pressure through the flow control module and pressure monitoring module;

[0044] The purge gas is delivered to the electrode surface of the battery through the purge pipe network to purge the electrode, and the purged gas is collected by the gas collection module;

[0045] The intelligent control system is used to collect data from pressure sensors and perform multi-sensor data fusion. It determines whether the pressure is normal based on the fused pressure data. If it is normal, normal purging is performed. If it is abnormal, the power is cut off and an alarm is issued. Based on the fused pressure data, it determines whether the oxygen concentration is greater than 5%. If so, the emergency device is triggered. If not, the gas evolution volume is calculated and the purge gas flow rate is dynamically adjusted according to the gas evolution volume.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The purge system of the present invention actively introduces an inert gas (such as nitrogen) to quickly remove the released hydrogen and oxygen from the battery system, directly avoiding the risk of oxygen contact with the electrodes and hydrogen accumulation. Compared with traditional methods, its advantages are:

[0048] It dynamically responds to the battery's operating status (such as triggering a purge when overcharged) in real time. It does not require changes to the electrolyte composition or electrode structure, ensuring compatibility. Through regular purges, it effectively controls the oxygen and hydrogen content within the battery, reduces impurity deposition and gas accumulation on the electrode surface, prevents safety hazards caused by gas accumulation, reduces explosion risks and the battery's internal resistance, improves the battery's charge and discharge efficiency, ensures safe battery operation, enhances safety, and extends the life of the electrolyte and electrodes. Through an intelligent control system, it can generate high-speed, directional gas jets to effectively remove impurities and gas from the electrode surface, improving purge efficiency. By optimizing the structure and control strategy of the purge system, it can ensure the stability and consistency of the battery during the charge and discharge process, improving the overall battery performance.

[0049] Furthermore, efficient purging is achieved through the multi-level branching design of the purge pipe network and the intelligent flow control module, which reduces the accumulation of impurities and gas inside the battery, and evenly removes impurities on the electrode surface, thereby reducing the self-discharge rate of the battery and improving the energy utilization efficiency of the battery.

[0050] Furthermore, through the cooperation of the control system and the sensor, the purge process can be automated and intelligently controlled, improving the convenience and safety of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of the intelligent purge system for zinc-nickel flow batteries of the present invention;

[0052] Figure 2 A flow chart for the purge gas supply;

[0053] Figure 3This is the flow control logic block diagram;

[0054] Figure 4 This is the structural diagram of the purge pipeline network;

[0055] Figure 5 It is the intelligent control logic diagram;

[0056] Figure 6 Schematic diagram of the gas collection device;

[0057] Figure 7 Schematic diagram of the structure of the purge system in Example 1;

[0058] In the figure, 1 is the purge gas supply device, 2 is the purge pipeline, 3 is the fuel cell stack, 4 is the control system, 1-1 is the air storage tank, 1-2 is the air compressor, 1-3 is the filter drying system, 1-4 is the nitrogen preparation machine, 1-5 is the nitrogen storage tank, and 1-6 is the pressure reducing valve. DETAILED DESCRIPTION

[0059] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in a variety of different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0060] The present invention uses intelligent closed-loop control and multi-stage gas distribution technology, combined with the real-time operating status of the zinc-nickel liquid flow battery (such as gas evolution volume, voltage and temperature), to dynamically adjust the flow rate, pressure and action area of ​​the purge gas to achieve precise and efficient oxygen and hydrogen removal.

[0061] See also Figure 1 The intelligent purge system for zinc-nickel flow batteries of the present invention includes a purge gas supply module, a flow control module, a purge pipeline network, a pressure monitoring module, a gas collection module, an intelligent control system, and a data storage and analysis module. The purge gas supply module is connected to the flow control module, which is connected to the purge pipeline network, which is connected to the zinc-nickel flow battery stack. A pressure monitoring module is provided on the purge pipeline network, and the zinc-nickel flow battery stack is connected to the gas collection module. The purge gas supply module, flow control module, pressure monitoring module, and battery internal gas collection module are all connected to the intelligent control system. The intelligent control system and gas collection module are both connected to the data storage and analysis module. These modules work together to form a closed-loop control system.

[0062] Purge gas supply module: uses high-purity nitrogen as purge gas and provides a stable nitrogen supply through a nitrogen preparation machine. Figure 2The module includes an air storage tank 1-1, an air compressor 1-2, a filter drying system 1-3, a nitrogen preparation machine 1-4 and a nitrogen storage tank 1-5. The air storage tank 1-1 is connected to the air compressor 1-2, the air compressor 1-2 is connected to the filter drying system 1-3, the filter drying system 1-3 is connected to the nitrogen preparation machine 1-4, the nitrogen preparation machine 1-4 is connected to the nitrogen storage tank 1-5, and the nitrogen storage tank 1-5 is used to store purge nitrogen. The air enters the nitrogen preparation machine 1-4 to prepare nitrogen, and is finally filled into the nitrogen storage tank 1-5, which compresses the nitrogen to the set pressure to meet the gas supply demand during the purge process. Among them, the filter drying system 1-3 is equipped with a gas dryer and a filter to ensure the dryness and purity of the purge gas and prevent moisture and impurities from entering the battery.

[0063] The technical principle of the purge gas supply module in the present invention is: high-purity nitrogen (purity ≥ 99.99%) is prepared by nitrogen preparation machines 1-4, and the purge gas is ensured to be free of moisture and impurities through an integrated compression-drying-storage process to avoid secondary contamination of the battery electrolyte.

[0064] The air compressor 1-2 (model: Gedes GJ-1103) compresses the air to 0.7-0.8MPa and inputs it into the filtration and drying system 1-3. The filtration and drying system 1-3 includes a connected molecular sieve drying tower and an activated carbon filter; the molecular sieve drying tower is connected to the air compressor 1-2, the activated carbon filter is connected to the nitrogen storage tank 1-5, the nitrogen storage tank 1-5 is connected to the pressure reducing valve 1-6, and the pressure reducing valve 1-6 is connected to the flow control module.

[0065] The molecular sieve drying tower is used to absorb moisture from the air, with a dew point of ≤-40°C;

[0066] The activated carbon filter is used to remove oil mist and particulate matter (filtration accuracy 0.01μm).

[0067] The dried air enters the nitrogen preparation machine 1-4 (using pressure swing adsorption PSA), absorbs oxygen through the carbon molecular sieve, and outputs nitrogen with a purity of ≥99.5%.

[0068] The nitrogen is buffered in nitrogen storage tank 1-5 (volume 1000L, working pressure 0.7MPa) and adjusted to the purge pressure (0.1-0.3MPa) through pressure reducing valve 1-6.

[0069] The present invention adopts a self-circulating drying design, and the molecular sieve drying tower is recycled through thermal regeneration technology (electrically heated to 200° C.), thereby reducing maintenance costs.

[0070] The nitrogen preparation machine 1-4 is pressure-linkedly controlled with the nitrogen storage tank 1-5, and the air compressor 1-2 is automatically started and stopped through feedback from the pressure sensor to avoid energy waste.

[0071] Flow Control Module: Connected to the purge gas supply module, this module precisely controls the purge gas flow rate. This module includes a connected mass flow meter and a flow control valve. The mass flow meter monitors the purge gas flow rate in real time, while the flow control valve automatically adjusts its opening based on feedback from the mass flow meter to achieve precise control of the purge gas flow rate and ensure stability and uniformity during the purge process.

[0072] The technical principle of the flow control module is: based on the PID closed-loop control algorithm, the gas flow is fed back in real time through the mass flow meter (MFM), and the flow control valve opening is adjusted to ensure that the deviation of the purge gas flow and the set value is ≤±2%.

[0073] A mass flow meter (model: Darhor DFG-6T, range 0-100 L / min) was installed at the inlet of the purge pipe to collect flow signals in real time;

[0074] The flow control valve (electric proportional valve, response time ≤ 0.5s) receives PID instructions from the intelligent control system and dynamically adjusts the opening;

[0075] When the pipeline pressure fluctuates (detecting the pressure sensor data), the flow set value is automatically corrected, that is, the pressure compensation algorithm is adopted to avoid flow deviation caused by pressure changes.

[0076] See also Figure 3 The intelligent control system updates the control instructions according to the gas evolution signal C / D of the battery, then performs pressure compensation correction, outputs the adjusted flow rate, and determines whether it is stationary. If it is stationary, it switches to 30% flow mode. If it is not stationary, it collects the flow signal and calculates the deviation through PID. If the deviation is greater than 2%, the valve opening is increased. If the deviation is ≤-2%, the valve opening is reduced.

[0077] In the present invention:

[0078] Dynamic flow matching: Automatically allocates the total flow (Q_total = N × Q_unit) according to the number of zinc-nickel flow battery cells (N) to avoid local over-blowing or under-blowing; where Q_total is the total flow and Q_unit is the flow of each battery cell.

[0079] Low flow energy-saving mode: When the battery is in a static state (no gassing signal), the flow rate is reduced to 30% of the maintenance flow rate to reduce inert gas consumption.

[0080] The purge pipe network includes purge pipes, which are made of corrosion-resistant, high-pressure-resistant materials with excellent flexibility and sealing properties. A gas flow control valve and pressure monitoring module are installed within the pipes, enabling real-time monitoring and adjustment of the purge gas flow and pressure to ensure stability and controllability during the purge process. One end is connected to the flow control module, and the other end extends into each battery cell of the zinc-nickel flow battery. The internal structure of the purge pipe network is designed as a multi-stage branching pipe structure, which ensures that the purge gas is evenly distributed to all corners of the battery cell, improving the purge effect.

[0081] The technical principle of the purge pipe network is to ensure that the purge gas evenly covers the electrode surface through multi-level branch pipes to eliminate dead corners.

[0082] See also Figure 4 The purge pipeline includes a first main pipeline, several branch pipelines, and a second main pipeline. The inlet of the first main pipeline is connected to the flow control module, and the outlet of the first main pipeline is connected to the inlet of each branch pipeline. The outlet of each branch pipeline is connected to the inlet of a battery cell of the zinc-nickel flow battery through a one-way valve. The outlet of each battery cell is connected to the inlet of the second main pipeline through a branch pipeline. Multiple branch pipelines are connected to different battery stacks 3, respectively, to achieve simultaneous purge of multiple battery electrodes.

[0083] Specifically, a branch pipe (material: PPR, pressure resistance 1.6 MPa) is connected to the inlet of the zinc-nickel flow battery stack 3;

[0084] Each battery cell corresponds to one branch pipe, and the inner diameter of the branch pipe is 8mm.

[0085] Anti-backflow design: A one-way valve is installed on the branch pipe to prevent the electrolyte from flowing back.

[0086] Pressure Monitoring Module: Installed on the purge pipeline network, it monitors the purge gas pressure in real time. This module includes a connected pressure sensor and a pressure display instrument. The pressure sensor converts the detected pressure signal into an electrical signal and transmits it to the pressure display instrument. The pressure display instrument allows operators to intuitively understand the changes in gas pressure during the purge process and ensure that the purge pressure remains within a safe range.

[0087] The internal battery gas collection module is located inside the battery cell of the zinc-nickel flow battery and is used to collect gases and residues discharged from the battery during the purge process. This module includes a collection pipe and a collection container. One end of the collection pipe connects to the interior of the battery cell and the other end is connected to the collection container. The collection container is equipped with a filter device that can filter and separate impurities such as solid particles and electrolyte from the gas. The collected gas can be discharged through the exhaust pipe, and the filtered impurities can be cleaned regularly.

[0088] The battery internal gas collection module also includes a nitrogen recovery circuit, which includes a nitrogen recovery compressor connected to the nitrogen storage tank 1-5. The purified gas is pressurized by the compressor and returned to the nitrogen storage tank 1-5, and the nitrogen is re-input into the purge system to achieve the recycling of nitrogen.

[0089] The technical principle of the gas collection module inside the battery cell is to avoid electrolyte loss and recover inert gas through gas-liquid separation + filtration recovery.

[0090] See also Figure 6 The collection container includes a gas-liquid separation tank, which includes a cyclone separator, a precision filter element and an activated carbon adsorption layer. The cyclone separator is connected to the precision filter element, and the precision filter element is connected to the activated carbon adsorption layer.

[0091] The collection pipe (material: PTFE) connects the battery exhaust port to the gas-liquid separation tank;

[0092] Cyclone separator: used to remove large droplets (efficiency ≥ 95%);

[0093] Precision filter element (pore size 0.1μm): used to intercept solid particles;

[0094] Activated carbon adsorption layer: used to absorb electrolyte vapor.

[0095] Intelligent control system: This system is connected to the purge gas supply module, flow control module, pressure monitoring module, and internal battery gas collection module to provide centralized control and automated management of the entire purge system. The intelligent control system includes a microprocessor, memory, and input / output interfaces. The microprocessor controls and coordinates each module through the I / O interfaces based on preset purge programs and parameters. The memory stores relevant data and historical records from the purge process. Operators can enter operating instructions and view purge status and data through a human-computer interface.

[0096] The technical principle of the intelligent control system is: based on multi-sensor fusion and fuzzy control algorithm, dynamic matching of purge parameters and battery status is achieved.

[0097] See also Figure 5 The microprocessor collects data from the pressure sensors and fuses the multi-sensor data. Based on this fused pressure data, it determines whether the pressure is normal. If it is, normal purge is performed. If it is abnormal, the power is cut off and an alarm is issued. Based on this fused pressure data, it determines whether the oxygen concentration is greater than 5%. If so, the emergency device is triggered. If not, the outgassing volume is calculated and the flow valve is dynamically adjusted based on the outgassing volume.

[0098] The input signals to the microprocessor include:

[0099] Battery status signals: voltage (0-2V), current (0-100A), temperature (20-60℃), electrolyte pH value (12-14);

[0100] Gas flow, pressure, and oxygen concentration of the purge system (detected by electrochemical sensor, accuracy ±0.1%).

[0101] The intelligent control system uses the gasification amount prediction model to calculate the gasification current: according to the voltage and current, the water electrolysis side reaction rate I_gasification is calculated (formula: I_gasification = k × (V-1.23V) × A), where I_gasification is the gasification current (unit: A); k is the reaction rate constant (unit: A / (V·m 2 )), which needs to be calibrated through experiments; V is the real-time working voltage (unit: V); A is the effective area of ​​the electrode (unit: m 2 ).

[0102] Priority scheduling: When the oxygen concentration is greater than 0.5%, the emergency purge mode is triggered (the flow rate is increased to 150%);

[0103] Fault self-diagnosis: If the pressure is abnormal (such as pipeline leakage), the gas source will be automatically cut off and an alarm will be sounded.

[0104] Upload data to the cloud via the 4G module, support remote parameter adjustment and troubleshooting, and realize wireless remote monitoring.

[0105] Data storage and analysis module: stores relevant data during the purge process and analyzes the data to provide a basis for subsequent optimization of purge parameters.

[0106] The zinc-nickel liquid flow battery purge system of the present invention has the following advantages:

[0107] (1) Reduce self-discharge: Through the multi-level branch design of the purge pipe network and the intelligent flow control module, efficient purge is performed to reduce the accumulation of impurities and gas inside the battery, and the impurities on the electrode surface are evenly removed, thereby reducing the self-discharge rate of the battery and improving the energy utilization efficiency of the battery.

[0108] (2) Control the generation of oxygen and hydrogen: Through the purging process, the oxygen and hydrogen content inside the battery can be effectively controlled to prevent safety hazards caused by gas accumulation and ensure the safe operation of the battery.

[0109] (3) Improve purging efficiency: Through the intelligent control system, a high-speed, directional gas jet can be generated to effectively remove impurities and gases on the electrode surface and improve purging efficiency.

[0110] (4) Extend battery life: Through regular purging operations, the impurity deposition and gas accumulation on the electrode surface can be reduced, the internal resistance of the battery can be reduced, the battery charging and discharging efficiency can be improved, and the battery service life can be extended.

[0111] (5) Improve battery performance: By optimizing the structure and control strategy of the purge system, the stability and consistency of the battery during the charging and discharging process can be ensured, thereby improving the overall performance of the battery.

[0112] (6) Intelligent control: Through the coordination of the control system and the sensor, the purge process can be automated and intelligently controlled, thus improving the convenience and safety of operation.

[0113] The present invention can achieve the following effects:

[0114] 1. Reduce self-discharge rate and improve energy utilization efficiency

[0115] Corresponding technical solution: Uniform removal of impurities on the electrode surface is achieved through the multi-level branching design of the purge pipeline network and the intelligent flow control module.

[0116] Experimental data:

[0117] Test conditions: A 50Ah zinc-nickel flow battery pack was used, the electrolyte was an electrolyte containing KOH and ZnO, wherein the KOH concentration was 6 mol / L and the ZnO concentration was 0.1 mol / L, and the ambient temperature was 25°C. The traditional mechanical purge system and the system of the present invention were compared.

[0118] result:

[0119] Residual oxygen concentration: 0.5% after conventional purging, reduced to 0.1% after purging with the present invention (detected by electrochemical sensor);

[0120] Self-discharge rate (capacity loss after 72 hours of standing): the traditional purge is 8.2%, while the present invention is reduced to 2.5% (measured by a capacity tester).

[0121] Theoretical analysis: The reduction of residual oxygen inhibits the oxidation of zinc anode (Zn+ 1 / 2O2→ZnO), reducing irreversible capacity loss.

[0122] 2. Control hydrogen / oxygen accumulation and improve safety

[0123] Corresponding technical solutions: cyclone separation and activated carbon adsorption design of the gas collection module, combined with the emergency purge mode of the intelligent control system.

[0124] Experimental data:

[0125] Test conditions: simulate overcharge conditions (voltage 2.1V, lasting 1 hour) to detect the hydrogen concentration inside the battery.

[0126] result:

[0127] Hydrogen gas volume fraction: the traditional purge system is 4% (close to the lower explosion limit of 4.1%), while the system of the present invention is reduced to 1.2% (gas chromatography analysis);

[0128] Oxygen concentration: reduced from 2.3% in traditional purging to 0.5%, meeting ATEX explosion-proof standards (oxygen concentration <5%).

[0129] Technical advantages: Eliminate explosion risks through real-time monitoring and dynamic purging.

[0130] 3. Improve purge efficiency and reduce energy consumption

[0131] Corresponding technical solution: The purge pipeline adopts the Venturi effect pipeline design.

[0132] Experimental data:

[0133] Test conditions: 10kW zinc-nickel flow battery stack, purge gas flow rate set to 50L / min.

[0134] result:

[0135] Purge time: The traditional system takes 30 minutes to purge 90% of the gas, while the present invention shortens this to 12 minutes (flow uniformity is improved);

[0136] Nitrogen consumption: The traditional system consumes 120L for a single purge, while the optimized system consumes 72L (40% energy saving).

[0137] Theoretical derivation: The Venturi structure balances the branch flow difference (deviation ≤ 5%) to avoid local gas retention.

[0138] 4. Extend battery cycle life

[0139] Corresponding technical solution: Directed purge technology prioritizes the removal of oxygen from the positive electrode area to reduce oxidation of the nickel positive electrode.

[0140] Experimental data:

[0141] Test conditions: 100 charge and discharge cycles (1C charge and discharge, DOD 80%), comparing the positive electrode capacity decay rate.

[0142] result:

[0143] Nickel positive electrode capacity retention rate: The traditional purge system is 72%, while the present invention increases it to 89% (constant current charge and discharge test);

[0144] Dendrite growth inhibition of zinc anode: SEM observation showed that the dendrite density was reduced by 60%.

[0145] Mechanism analysis: Reduce the side reaction of NiOOH peroxidation (NiOOH→NiO2+H + ), maintaining the stability of the positive electrode structure.

[0146] 5. Improve battery charging and discharging performance

[0147] Corresponding technical solution: The gas evolution amount prediction model of the intelligent control system dynamically adjusts the flow valve according to the gas evolution amount.

[0148] Experimental data:

[0149] Test conditions: 1C rate charge and discharge, comparison of energy efficiency.

[0150] result:

[0151] Energy efficiency (discharge capacity / charge capacity): The traditional system is 82%, and the present invention is improved to 86%;

[0152] Voltage fluctuation range: reduced from ±50mV to ±15mV (measured by high-precision voltage acquisition module).

[0153] Technical principle: Dynamically adjust the purge flow rate (Q = k·I_gassing) to reduce the obstruction of the gas film to the electrode reaction.

[0154] 6. Achieve intelligence and convenient operation

[0155] Description of experimental method:

[0156] Gas concentration detection: electrochemical sensor (Maxtec series) and gas chromatograph (Agilent 7890B);

[0157] Cycle life test: Arbin BT2000 battery testing system;

[0158] Energy consumption calculation: nitrogen flow meter cumulative reading and time integration.

[0159] Table 1 Comparison of the effects of the purging method of the present invention and the traditional purging technology

[0160] index Traditional purge technology The present invention Improvement Residual oxygen concentration 0.50％ ≤0.1％ 80% reduction Hydrogen explosion risk Close to the lower explosion limit (4.1%) Safety range (<2%) Risk dropped by 75% Nitrogen consumption per purge 120 L 72L Save 40% Nickel cathode cycle life 100 times (capacity retained 72%) 100 times (capacity retained 89%) 24% longer lifespan Energy efficiency 82％ 93％ 11% increase Frequency of manual intervention 2 hours per day No daily intervention required Automation rate 100%

[0161] Referring to Table 1, we can see that:

[0162] 1. Improved purge efficiency: residual oxygen concentration ≤ 0.1%, zinc cathode oxidation rate reduced by 80%;

[0163] 2. Reduced energy consumption: Through dynamic flow control, nitrogen consumption is reduced by 40%;

[0164] 3. Enhanced safety: The risk of hydrogen accumulation is reduced by 90%, in line with ATEX explosion-proof standards;

[0165] 4. Compatibility optimization: No need to change the electrode or electrolyte formula, adapt to the existing zinc-nickel flow battery architecture.

[0166] The technical solutions in the embodiments of the present invention are described clearly and completely below.

[0167] (1) First, according to the specifications and capacity of the zinc-nickel liquid flow battery, determine the volume of the gas storage tank in the purge gas supply module and the power of the gas compressor to ensure that they can meet the gas supply requirements during the purge process.

[0168] (2) Install and connect the purge gas supply module, flow control module, purge pipeline network, pressure monitoring module, battery internal gas collection module and intelligent control system in accordance with the design requirements, ensuring that the connections between the modules are tight and reliable and the pipelines are unobstructed.

[0169] (3) Before the purging operation, the purging parameters, including the flow rate, pressure, and purging time of the purging gas, shall be set through the human-machine interface of the intelligent control system, and reasonable adjustments shall be made according to the actual status and needs of the battery.

[0170] (4) Starting the purge gas supply module, the gas compressor compresses the inert gas in the gas storage tank to a set pressure, and then enters the purge pipeline network through the flow control module to evenly purge the interior of each battery cell of the zinc-nickel liquid flow battery.

[0171] (5) During the purging process, the pressure monitoring module monitors the pressure of the purging gas in real time and feeds back the pressure signal to the intelligent control system. The intelligent control system automatically adjusts the flow control valve in the flow control module according to the pressure signal to ensure that the purging pressure is stable within the set range.

[0172] (6) The gas collection module inside the battery collects the gas and residue discharged during the purge process, and the filter device filters and separates the impurities in the gas. The collected gas is discharged through the exhaust pipe, and the impurities are cleaned regularly.

[0173] (7) After the purge is completed, the intelligent control system automatically records the relevant data and parameters of the purge process and stores the data in the memory for subsequent query and analysis.

[0174] Through the above embodiments, the zinc-nickel liquid flow battery purge system of the present invention can achieve efficient and safe purge of the inside of the zinc-nickel liquid flow battery, effectively solves the problems existing in the existing purge technology, and has significant economic and social benefits.

[0175] Example 1

[0176] See also Figure 7The zinc-nickel liquid flow battery purge system of the present invention includes a purge gas supply device 1, a purge pipeline 2, a fuel cell stack 3 and a control system 4. The purge gas supply device 1 uses homemade high-purity nitrogen as the purge gas, and provides a stable nitrogen supply through a nitrogen preparation machine. The nitrogen preparation machine has the characteristics of efficient nitrogen production and low energy consumption, and can meet the requirements of the purge process for nitrogen purity and flow. The gas supply device is equipped with a gas dryer and a filter to ensure the dryness and purity of the purge gas. The purge pipeline 2 is made of corrosion-resistant and high-pressure resistant materials and has good flexibility and sealing. A gas flow regulating valve and a pressure sensor are provided inside the pipeline, which can monitor and adjust the flow and pressure of the purge gas in real time. The control system 4 is connected to the purge gas supply device 1, the purge pipeline 2 and the fuel cell stack 3, and collects the operating parameters of the battery and the data during the purge process through sensors to automatically adjust the supply of purge gas.

[0177] Example 2

[0178] In another zinc-nickel liquid flow battery energy storage system, the intelligent purge system of the present invention is used for purge.

[0179] The battery status monitoring module obtains real-time battery status parameters, including voltage of 2.8V, current of 15A, temperature of 30°C, and electrolyte concentration of 35%. Based on these parameters, the intelligent control module sets the purge gas to pure nitrogen, with a flow rate of 0.8L / min and a pressure of 0.12MPa. The purge gas supply module provides the corresponding purge gas and ensures the stability of the gas flow and pressure through the flow control module and pressure monitoring module. During the purge process, the intelligent control module monitors the battery status parameters in real time and adjusts the purge parameters as needed to achieve intelligent purge. After purge, the battery performance and lifespan are significantly improved, and impurity deposits on the electrode surface are effectively removed.

[0180] The core innovation of the zinc-nickel flow battery purge system of the present invention lies in the combination of a closed-loop intelligent control mechanism and high-precision gas management technology. Its key technical solutions can be summarized as follows:

[0181] 1. Core Architecture

[0182] High-purity nitrogen supply: Through the nitrogen preparation machine (PSA technology) + compression drying system, a moisture-free and impurity-free inert gas source (purity ≥ 99.5%) is provided to avoid secondary contamination from the source.

[0183] Multi-level branch purge pipeline network: using corrosion-resistant and high-pressure resistant flexible pipelines (such as PPR+fluororubber interface), combined with Venturi effect pipeline design, to achieve uniform gas coverage of the electrode surface and eliminate local dead corners.

[0184] Closed-loop intelligent control system: Based on real-time monitoring data of battery operating status (voltage, current, temperature, gassing volume), the system automatically adjusts purge parameters (flow rate, pressure, trigger timing) through a gassing volume prediction model and PID closed-loop control algorithm.

[0185] 2. Key data analysis methods

[0186] (1) Gas evolution prediction model

[0187] Input parameters: battery voltage (V), current (I), temperature (T), and electrolyte pH value.

[0188] Algorithm principle: According to the kinetic formula of water electrolysis side reaction, I_gassing = k×(V-1.23V)×A), I_gassing is the gassing current (unit: A); k is the reaction rate constant (unit: A / (V·m 2 )), which needs to be calibrated through experiments; V is the real-time working voltage (unit: V); A is the effective area of ​​the electrode (unit: m 2 ).

[0189] (2) Control output: Dynamically adjust the purge flow rate Q = α × I_gas (α is the proportional coefficient) to achieve on-demand purge.

[0190] Coordinated control of multiple battery cells: For a parallel stack system (N cells), the total flow rate Q_total = Σ(Q_i), where the flow rate of each cell Q_i = Q_base + β × (C_O2_i - C_threshold) (C_O2_i is the cell oxygen concentration, and C_threshold is the threshold value).

[0191] Pressure-flow decoupling control: PID closed-loop control algorithm is used to compensate for pipeline pressure fluctuations, ensuring flow deviation ≤±2%.

[0192] In the present invention, the purge gas supply device + purge pipeline + control system realizes the integrated design of nitrogen supply, pipeline network, and closed-loop control; a gas dryer and filter are provided to ensure high-purity gas: drying (dew point ≤-40°C) and filtration (0.01μm). The corrosion-resistant and high-pressure resistant purge pipeline can be flexibly connected to prevent deformation, and the Venturi design adopted can balance the flow; the sensor collects battery operating parameters for the purpose of multi-source data fusion (voltage, current, temperature, gas concentration); multi-branch pipelines connect multiple battery stacks to support large-scale battery stacks in parallel to avoid uneven flow distribution; the purge system is integrated with the battery management system, and the operating status of the battery is monitored and analyzed in real time through the BMS, and the purge parameters (purge frequency and purge intensity) are automatically adjusted in real time. The purge frequency is optimized based on the battery health status (SOH) prediction to extend the life.

[0193] 3. Implementation examples of key data analysis and control

[0194] Scenario: Emergency purge triggered when battery is overcharged

[0195] 1. Data collection: The BMS detects voltage exceeding the limit (>2.0V) and temperature rising (ΔT>5℃ / min);

[0196] 2. Calculation of gas evolution: The model predicts that the hydrogen generation rate is 0.5 L / min and the oxygen generation rate is 0.25 L / min;

[0197] 3. Control response:

[0198] The flow control module switches to emergency mode (Q = 150% rated flow);

[0199] The purge pipeline distributes nitrogen preferentially to the cathode area (directional purge accounts for 70%);

[0200] Effect verification: The oxygen concentration dropped from 1.2% to 0.3% within 30 seconds, and the voltage fell back to a safe range.

[0201] The core of the technical solution of this invention is to deeply combine data-driven closed-loop control (gas volume prediction, dynamic flow matching, fault diagnosis) with hardware structure innovation (multi-stage pipeline, Venturi design, gas-liquid separation and recovery), solving the problems of low efficiency, high energy consumption and poor adaptability of traditional purge systems. Its special features are reflected in:

[0202] 1. Accurate prediction: real-time calculation based on gas evolution volume;

[0203] 2. Dynamic response: multi-parameter coordinated flow and pressure decoupling control;

[0204] 3. System compatibility: seamless integration with BMS, adaptable to large-scale energy storage scenarios.

[0205] The above description is merely a description of the preferred embodiment of the present invention and is not to be construed as limiting the claims. The present invention is not limited to the above embodiment, and variations in the specific structure are permitted. Any variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0206] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. An intelligent purge system for zinc-nickel flow batteries, characterized in that: It includes purge gas supply module, flow control module, purge pipeline network, pressure monitoring module, gas collection module and intelligent control system; Among them, the purge gas supply module is connected to the flow control module, the flow control module is connected to the purge pipeline network, the purge pipeline network is connected to the zinc-nickel liquid flow battery stack, the zinc-nickel liquid flow battery stack is connected to the gas collection module, the purge gas supply module, the flow control module, the pressure monitoring module and the gas collection module are all connected to the intelligent control system; a pressure monitoring module is set on the purge pipeline network.

2. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The purge gas supply module includes an air storage tank (1-1), an air compressor (1-2), a filter drying system (1-3), a nitrogen preparation machine (1-4) and a nitrogen storage tank (1-5); The air storage tank (1-1) is connected to the air compressor (1-2), the air compressor (1-2) is connected to the filter drying system (1-3), the filter drying system (1-3) is connected to the nitrogen preparation machine (1-4), and the nitrogen preparation machine (1-4) is connected to the nitrogen storage tank (1-5).

3. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The flow control module includes a connected mass flow meter and a flow control valve. Based on the PID closed-loop control algorithm, the gas flow is fed back in real time through the mass flow meter to adjust the opening of the flow control valve so that the deviation between the purge gas flow and the set value is ≤±2%.

4. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The intelligent control system is used to update the control instructions according to the gas evolution signal of the battery, and then perform pressure compensation correction, output the adjusted flow, and determine whether it is stationary. If it is stationary, switch to 30% flow mode. If it is not stationary, collect the flow signal, calculate the deviation through PID, if the deviation is greater than 2%, increase the valve opening, if the deviation is ≤-2%, reduce the valve opening.

5. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The purge pipe network includes multi-stage branch purge pipes, which are equipped with gas flow regulating valves and pressure monitoring modules. One end of the purge pipe is connected to the flow control module, and the other end extends to the interior of each battery cell of the zinc-nickel liquid flow battery.

6. The intelligent purge system for zinc-nickel flow batteries according to claim 5, characterized in that: The multi-stage branch purge pipeline includes a first main pipeline, several branch pipelines and a second main pipeline. The inlet of the first main pipeline is connected to the flow control module, the outlet of the first main pipeline is connected to the inlet of each branch pipeline, the outlet of each branch pipeline is connected to the inlet of a battery cell of the zinc-nickel liquid flow battery through a one-way valve, and the outlet of each battery cell is connected to the inlet of the second main pipeline through a branch pipeline.

7. The intelligent purge system for zinc-nickel flow batteries according to claim 5, characterized in that: The pressure monitoring module includes a connected pressure sensor and a pressure display instrument. The pressure sensor converts the detected pressure signal into an electrical signal and transmits it to the pressure display instrument.

8. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The gas collection module is arranged inside the battery cell of the zinc-nickel liquid flow battery. The battery internal gas collection module includes a collection pipe and a collection container. One end of the collection pipe is connected to the inside of the battery cell, and the other end is connected to the collection container. A filtering device is arranged inside the collection container. The gas collection module also includes a nitrogen recovery loop, which includes a nitrogen recovery compressor connected to the purge gas supply module.

9. The intelligent purge system for zinc-nickel flow batteries according to claim 1, characterized in that: The collecting container comprises a gas-liquid separation tank, which comprises a cyclone separator, a precision filter element and an activated carbon adsorption layer. The cyclone separator is connected to the precision filter element, which is connected to the activated carbon adsorption layer.

10. An intelligent purging method for zinc-nickel flow battery based on the system according to claim 1, characterized in that: include: Obtain real-time battery status parameters, including voltage, current, temperature and electrolyte concentration; According to the real-time status parameters of the battery and the preset purge strategy, set the purge parameters, including gas type, flow rate and pressure; The purge gas supply module provides the corresponding purge gas according to the set purge parameters, and monitors the gas flow and pressure through the flow control module and pressure monitoring module; The purge gas is delivered to the electrode surface of the battery through the purge pipe network to purge the electrode, and the purged gas is collected by the gas collection module; The intelligent control system determines whether the pressure is normal. If it is normal, normal purging is performed. Based on the fused pressure data, it is determined whether the oxygen concentration is greater than 5%. If not, the gas evolution volume is calculated and the purge gas flow rate is dynamically adjusted based on the gas evolution volume.

Images