A bms management system and management method for a flow battery
By constructing a full-temperature-range state estimation model and closed-loop control logic, the problems of accurate estimation and multi-system coordinated control of flow battery BMS in extreme environments were solved, improving battery operating efficiency and lifespan, and reducing operation and maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI JUHE INTELLIGENT TECHNOLOGY CO LTD
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-29
AI Technical Summary
Existing flow battery BMS management systems suffer from problems such as large SOC estimation errors, inaccurate charge and discharge control, and lagging safety protection in complex scenarios such as high-latitude low temperatures, outdoor high temperatures, and dynamic changes in electrolyte circulation, leading to shortened battery life and increased operation and maintenance costs.
A full-temperature-range state estimation model, an electrolyte circulation and charge/discharge control model, and a system management model are adopted. Combined with temperature and electrolyte concentration dual-factor correction logic, a closed-loop control logic is constructed to achieve accurate SOC/SOH estimation and multi-system collaborative control, including high and low temperature charge/discharge resistance, thermal management, and safety protection.
It achieves a SOC estimation error of less than ±2.5% and a SOH estimation error of less than ±2.8% in extreme temperature ranges, reduces electrolyte high-temperature loss by 40%, and improves charge and discharge efficiency by 35%, adapting to complex operating conditions, extending battery life and reducing operation and maintenance costs.
Smart Images
Figure CN122117956A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flow battery management technology, and in particular to a BMS management system and management method for flow batteries. Background Technology
[0002] Flow batteries, with their core advantages such as independently adjustable capacity, long cycle life (≥10,000 cycles), and high safety (no risk of thermal runaway), have become the mainstream technology in the field of electrochemical energy storage and are widely used in scenarios such as new energy consumption, grid peak shaving, and distributed energy storage. The battery management system (BMS), as the "brain" of the flow battery, undertakes key functions such as battery state monitoring (SOC / SOH estimation), precise charge and discharge control, safety protection, and multi-system coordination. Its performance directly determines the operating efficiency, cycle life, and total lifecycle maintenance cost of the flow battery.
[0003] The control logic of existing flow battery BMS management systems is only suitable for normal operating conditions at room temperature. In complex scenarios such as high-latitude low temperatures, outdoor high temperatures, and dynamic changes in electrolyte circulation, the technical defects are significantly amplified. The specific reproducible defects and their causes are as follows:
[0004] 1. Double error superposition in low temperature environment (≤-10℃): The voltage sampling harness of traditional BMS increases in impedance at low temperature, resulting in a sampling delay of over 220ms. The SOC estimation model lacks low temperature dynamic correction logic, and the estimation error reaches ±12%~±15%. The power consumption of charge and discharge switching devices increases by more than 5 times at low temperature, the false over-temperature protection rate reaches 38%, and the charge and discharge cutoff voltage is not dynamically adjusted. Frequent undercharging and over-discharging shortens the battery cycle life to 68% of the design value.
[0005] 2. High-temperature environment (≥45℃) device drift and system disconnection: The accuracy of electrical parameter acquisition devices drifts at high temperatures, the voltage measurement drift increases by more than 4 times, the current linearity deviation exceeds 11%, and the SOC estimation error reaches ±9%~±11%; the main controller's insufficient heat dissipation leads to a downtime risk of up to 36%, and there is no direct coordination logic between BMS, TMS, and electrolyte circulation system, the high-temperature heat dissipation start-up is delayed by 15 minutes, the electrolyte high-temperature hydrolysis rate is accelerated by 3 times, and the loss increases by 40%. Summary of the Invention
[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a BMS management system and management method for flow batteries.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A BMS management system for a flow battery includes a sensing layer, a control layer, an execution layer, a communication layer, and a power module. The sensing layer is used to collect various parameters of the flow battery, and includes a wide-temperature-range electrical parameter acquisition unit, a distributed temperature acquisition unit, an electrolyte circulation parameter acquisition unit, and a battery health status auxiliary acquisition unit.
[0009] The control layer is the core processing unit of the system. It realizes accurate estimation of battery state, electrolyte circulation and charge-discharge control and issues precise control commands through built-in models. The built-in models of the control layer include a full-temperature-range state estimation model, an electrolyte circulation and charge-discharge control model and a system management model.
[0010] The execution layer receives instructions from the control layer and performs actions such as charge / discharge regulation, thermal management, electrolyte circulation and concentration correction, and graded safety protection. The execution layer includes a high and low temperature resistant charge / discharge control unit, a thermal management execution unit, an electrolyte circulation regulation unit, and a safety protection execution unit.
[0011] The communication layer enables real-time data interaction between local layers, and simultaneously completes remote data uploading, command issuance, and fault push with the cloud.
[0012] The power module is used to provide stable power to each level.
[0013] Preferably, the wide-temperature-range electrical parameter acquisition unit is used to acquire the current and voltage data of the flow battery, and the distributed temperature acquisition unit is used to acquire the temperature values of the battery stack, electrolyte storage tank, and circulation pipeline. The battery stack temperature acquisition points are located on each electrode, the electrolyte storage tank temperature acquisition points are located at the top, middle, and bottom of the tank, and the circulation pipeline temperature acquisition points are located at the inlet, outlet, and intermediate nodes of the pipeline. The spacing between intermediate nodes in the circulation pipeline is set to 4.5 cm, and the data from each acquisition point is filtered using a median value with a window size of 5. The electrolyte circulation parameter acquisition unit is used to acquire the flow rate, concentration, and pressure parameters of the electrolyte. The battery health status auxiliary acquisition unit uses a 1kHz high-frequency impedance method to acquire the internal resistance of individual battery cells in real time, with the acquisition period synchronized with the voltage acquisition.
[0014] Preferably, the full-temperature-range state estimation model achieves accurate SOC / SOH estimation by constructing a correction logic that couples temperature and electrolyte concentration parameters. The correction logic is as follows:
[0015] For temperature correction factor , ,in For the electrolyte temperature, when T≤-10℃, a low-temperature compensation coefficient of 1.05 is added; when T≥45℃, a high-temperature compensation coefficient of 0.98 is added.
[0016] For concentration correction factor ,in For the real-time concentration of the electrolyte, when <1.0 mol / L or When the concentration is >1.6 mol / L, a concentration compensation coefficient of 0.95 is applied.
[0017] The closed-loop estimation method is as follows: ,in For the initial SOC, This is the charging and discharging current. For charging and discharging efficiency, To calibrate the SOC value twice every minute using the open-circuit voltage, based on the battery's rated capacity.
[0018] SOH (State of Health) estimation integrates three parameters: cell internal resistance, cycle life, and capacity decay rate, taking into account the weighted impact of each parameter on battery health. The weighting is 4:3:3, and the specific quantitative estimation formula is as follows:
[0019] in This represents the current internal resistance of a single battery cell. The internal resistance of a single cell in a brand-new battery state; This refers to the actual number of battery cycles. The rated number of battery cycles, For the battery's rated capacity, This represents the current actual capacity of the battery.
[0020] Preferably, the quantization matching rules for the electrolyte circulation and charge / discharge control model are as follows:
[0021] The electrolyte flow rate and charge / discharge rate matching rules are as follows:
[0022] When the flow rate is 2~3L / min, the rate limit is 0.2C~0.3C; when the flow rate is 3~5L / min, the rate limit is 0.3C~0.8C; when the flow rate is 5~8L / min, the rate limit is 0.8C~1.2C; when the flow rate is <2L / min or >8L / min, charging and discharging should be stopped immediately and the flow rate should be adjusted first.
[0023] The electrolyte concentration and charge / discharge rate matching rules are as follows:
[0024] At concentrations of 1.2–1.4 mol / L, full-rate charge / discharge at 1.2C is permissible; at concentrations of 1.0–1.2 mol / L or 1.4–1.5 mol / L, the rate is reduced by 30%; at concentrations <1.0 mol / L or >1.5 mol / L, concentration regulation is activated and the rate is reduced by 50%.
[0025] In addition, when the electrolyte pressure exceeds the threshold of 0.1~0.5MPa, the flow rate is adjusted by adjusting the speed of the circulating pump. If the pressure is too high, the flow rate is reduced; if the pressure is too low, the flow rate is increased. The charging and discharging current is adjusted simultaneously.
[0026] Preferably, when the system control model is in a low-temperature state below -5℃, the preheating unit is started and the circulating pump runs at 30% of the rated speed; when T rises to 5℃, the power of the preheating unit is reduced to 50%; when T rises to 15℃, the preheating unit is turned off and the circulating pump returns to the rated speed, allowing low-rate charging and discharging at 0.2C; after T stabilizes above 15℃ for 30 minutes, the normal charging and discharging rate is restored.
[0027] Preferably, when the temperature is above 40°C, the circulation pump speed is increased to 120% of the rated speed; when T≥45°C, the battery equalization interval is shortened to 45 minutes, and the charging and discharging current limit is reduced by 12% for every 5°C increase; when T≥55°C, charging and discharging are suspended, and only heat dissipation and electrolyte circulation are maintained; charging and discharging are gradually resumed after T drops below 45°C.
[0028] The management method of the BMS management system for a flow battery, as described above, includes the following steps:
[0029] S1. System initialization and parameter preset: After the system starts, it completes self-test of power supply and communication links at each level, loads preset parameter thresholds in the control layer, and enters standby mode in the execution layer. If the self-test fails, an early warning is triggered and the fault is located.
[0030] S2. Real-time acquisition and preprocessing of all parameters: The sensing layer synchronously acquires electrical parameters, temperature, electrolyte circulation parameters, and monomer internal resistance at a frequency of 100Hz, judges the validity of the data in real time, performs moving average filtering or median filtering preprocessing on the acquired data, and uploads the preprocessed data to the control layer at a period of 10ms.
[0031] S3. Accurate estimation of battery state across the entire temperature range: The control layer inputs preprocessed data into the full-temperature-range state estimation model and dynamically estimates SOC / SOH through temperature and concentration dual-factor coupling correction logic. SOC is calibrated twice every minute and SOH is updated once every hour.
[0032] S4. Electrolyte circulation and charge / discharge control: The control layer compares the electrolyte parameters with the preset threshold and adjusts the charge / discharge rate and circulation pump speed and flow rate through a collaborative control model. After the parameters are restored to the threshold range, the normal rate is gradually restored, forming a closed-loop regulation.
[0033] S5. System management: The control layer triggers the low-temperature or high-temperature control logic of the system management model based on the electrolyte and battery stack temperatures, enabling real-time synchronous monitoring of the BMS, TMS, and electrolyte circulation system until the temperature returns to the normal range.
[0034] S6. Safety protection: The control layer monitors the system operating parameters in real time, triggers corresponding protection based on the degree of parameter deviation from the threshold, and resets the system according to the corresponding rules after the fault is cleared.
[0035] S7. Data storage and remote debugging: The control layer stores the entire process data locally. Raw acquired data is retained for 30 days, SOC / SOH estimation results are retained for 90 days, and control commands and protection action records are permanently retained. It supports real-time viewing of parameters, remote modification of preset thresholds, and reading of operation logs to locate faults on the cloud platform. Specifically, data storage: The control layer stores the entire process operation data locally. Raw acquired data (one record every 10ms) is retained for 30 days, SOC / SOH estimation results (one record every 1min) are retained for 90 days, and control commands and protection action records (including abnormal parameters and processing results) are permanently retained. It supports data backtracking and fault location.
[0036] Remote debugging: Staff can view real-time system operating parameters through a cloud platform and remotely modify preset parameters such as charge / discharge rate and temperature threshold (modification commands require secondary confirmation, and records are automatically saved); in case of system failure, the operating log can be remotely read to accurately locate the faulty component (acquisition / control / execution unit) and guide on-site maintenance.
[0037] Preferably, the preset core parameter thresholds in step S1 are: electrolyte flow rate 2~8L / min, concentration 1.2~1.4mol / L, pressure 0.1~0.5MPa; low temperature preheating threshold ≤-5℃, high temperature heat dissipation threshold ≥40℃; charging cut-off voltage 1.6V / cell, discharging cut-off voltage 0.85V / cell.
[0038] Preferably, the filtering rules in step S2 are as follows: voltage and current are filtered using a moving average with a window size of 10, and temperature and electrolyte concentration are filtered using a median value with a window size of 5 to eliminate instantaneous interference.
[0039] The present invention has the following beneficial effects:
[0040] 1. By constructing a dual-factor coupled correction logic based on temperature and electrolyte concentration, the limitations of traditional single-parameter correction are overcome. Dynamic adjustment of SOC / SOH is achieved through quantitative formulas, ultimately achieving an SOC estimation error of ≤±2.5% and an SOH estimation error of ≤±2.8%, representing a 75% improvement in accuracy compared to traditional methods. This completely solves the core problem of large estimation deviations under extreme temperature ranges.
[0041] 2. By constructing a closed-loop control logic for the three systems of electrolyte circulation, charging and discharging, and thermal management, and clarifying the quantitative matching rules for flow rate, concentration, and rate, the synchronization of low-temperature preheating and charging and discharging reaches 100%, the high-temperature heat dissipation response time is shortened to within 1 minute, the overall operating efficiency of the flow battery is improved by more than 35%, and the high-temperature electrolyte loss is reduced by 40%.
[0042] 3. This invention focuses on operation control logic, eliminates redundant models, clarifies the quantitative rules, closed-loop mechanism, response threshold and execution process of each link, and is compatible with mainstream flow batteries such as vanadium redox flow batteries and zinc-bromine redox flow batteries. It is especially suitable for complex energy storage scenarios such as high latitude low temperature, outdoor high temperature and uneven electrolyte circulation. Attached Figure Description
[0043] Figure 1 This is a system architecture block diagram of a BMS management system for a flow battery proposed in this invention. Detailed Implementation
[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0045] Reference Figure 1 A BMS management system for a flow battery includes a sensing layer, a control layer, an execution layer, a communication layer, and a power module. The sensing layer is used to collect various parameters of the flow battery and includes a wide-temperature-range electrical parameter acquisition unit, a distributed temperature acquisition unit, an electrolyte circulation parameter acquisition unit, and a battery health status auxiliary acquisition unit.
[0046] The control layer is the core processing unit of the system. It uses built-in models to accurately estimate the battery state, control the electrolyte circulation and charge / discharge, and issue precise control commands. The built-in models of the control layer include a full-temperature-range state estimation model, an electrolyte circulation and charge / discharge control model, and a system management model.
[0047] The wide-temperature-range electrical parameter acquisition unit is used to collect current and voltage data of the flow battery. The distributed temperature acquisition unit collects temperature values from the battery stack, electrolyte storage tank, and circulation pipeline. Temperature acquisition points for the battery stack are located on each electrode; for the electrolyte storage tank, they are located at the top, middle, and bottom; and for the circulation pipeline, they are located at the inlet, outlet, and intermediate nodes. The spacing between intermediate nodes in the circulation pipeline is set to 4.5 cm. Data from each acquisition point is filtered using a median value with a window size of 5. The electrolyte circulation parameter acquisition unit collects the flow rate, concentration, and pressure parameters of the electrolyte. Specifically, flow rate is calculated using pulse counting logic, with the formula: flow rate = 0.1 × pulse frequency (Hz), accuracy ±0.08 L / min; concentration is calculated using optical refraction, converting the output analog signal to real-time concentration, accuracy ±0.008 mol / L; and pressure is calculated using voltage signal feedback logic, with the formula: pressure = 0.2 × output voltage (V), accuracy ±0.009 MPa. All three parameters are acquired synchronously, with the upload cycle consistent with the electrical parameters.
[0048] The battery health status auxiliary acquisition unit uses a 1kHz high-frequency impedance method to acquire the internal resistance of individual battery cells in real time, and the acquisition period is synchronized with the voltage acquisition.
[0049] The full-temperature-range state estimation model achieves accurate SOC / SOH estimation by constructing a correction logic that couples temperature and electrolyte concentration parameters. The correction logic is as follows:
[0050] For temperature correction factor , ,in For the electrolyte temperature, when T≤-10℃, a low-temperature compensation coefficient of 1.05 is added; when T≥45℃, a high-temperature compensation coefficient of 0.98 is added.
[0051] For concentration correction factor ,in For the real-time concentration of the electrolyte, when <1.0 mol / L or When the concentration is >1.6 mol / L, a concentration compensation coefficient of 0.95 is applied.
[0052] The closed-loop estimation method is as follows: ,in For the initial SOC, This is the charging and discharging current. For charging and discharging efficiency, To calibrate the SOC value twice every minute using the open-circuit voltage, based on the battery's rated capacity.
[0053] SOH (State of Health) estimation integrates three parameters: cell internal resistance, cycle life, and capacity decay rate, taking into account the weighted impact of each parameter on battery health. The weighting is 4:3:3, and the specific quantitative estimation formula is as follows:
[0054] in This represents the current internal resistance of a single battery cell. The internal resistance of a single cell in a brand-new battery state; This refers to the actual number of battery cycles. The rated number of battery cycles, For the battery's rated capacity, This represents the current actual capacity of the battery.
[0055] The quantization matching rules for the electrolyte circulation and charge / discharge control model are as follows:
[0056] The electrolyte flow rate and charge / discharge rate matching rules are as follows:
[0057] When the flow rate is 2~3L / min, the rate limit is 0.2C~0.3C; when the flow rate is 3~5L / min, the rate limit is 0.3C~0.8C; when the flow rate is 5~8L / min, the rate limit is 0.8C~1.2C; when the flow rate is <2L / min or >8L / min, charging and discharging should be stopped immediately and the flow rate should be adjusted first.
[0058] The electrolyte concentration and charge / discharge rate matching rules are as follows:
[0059] At concentrations of 1.2–1.4 mol / L, full-rate charge / discharge at 1.2C is permissible; at concentrations of 1.0–1.2 mol / L or 1.4–1.5 mol / L, the rate is reduced by 30%; at concentrations <1.0 mol / L or >1.5 mol / L, concentration regulation is activated and the rate is reduced by 50%.
[0060] In addition, when the electrolyte pressure exceeds the threshold of 0.1~0.5MPa, the flow rate is adjusted by adjusting the speed of the circulating pump. If the pressure is too high, the flow rate is reduced; if the pressure is too low, the flow rate is increased. The charging and discharging current is adjusted simultaneously.
[0061] When the temperature is below -5℃, the system control model starts the preheating unit and the circulating pump runs at 30% of its rated speed. When T rises to 5℃, the power of the preheating unit is reduced to 50%. When T rises to 15℃, the preheating unit is shut down and the circulating pump returns to its rated speed, allowing low-rate charging and discharging at 0.2C. After T stabilizes above 15℃ for 30 minutes, the normal charging and discharging rate is restored.
[0062] The execution layer receives instructions from the control layer and performs actions such as charge and discharge regulation, thermal management, electrolyte circulation and concentration correction, and graded safety protection. The execution layer includes a high and low temperature charge and discharge control unit, a thermal management execution unit, an electrolyte circulation regulation unit, and a safety protection execution unit.
[0063] Specifically, the high and low temperature charge and discharge control unit adopts low-resistance switching devices and parallel topology, with a conduction resistance of ≤4.8mΩ at -30℃. It has built-in low temperature start-up logic and automatically starts 5W preheating for 10 minutes at -20℃. In addition, the unit also integrates active balancing logic, which starts a 1A balancing circuit when the voltage difference between individual cells is ≥50mV, with a balancing time of ≤3 minutes to ensure the consistency of individual cell voltage.
[0064] The thermal management execution unit includes a preheating module and a heat dissipation module, and is controlled by a multi-system linkage management and control model: the preheating module is installed at the bottom of the liquid storage tank, with a heating efficiency of ≥90%, and the power is adjusted according to the temperature threshold; the heat dissipation module adopts a combination of liquid cooling and air cooling logic, with liquid cooling starting at ≥40℃ and air cooling superimposed at ≥45℃, and precise heat dissipation is achieved by adjusting the water pump speed and the air duct speed, and the electrolyte temperature can be controlled below 40℃ at 45℃.
[0065] The flow rate regulation of the electrolyte circulation unit adopts a stepless speed-regulating circulation pump with a speed regulation accuracy of ±50 r / min and a response delay of ≤10 ms; the concentration regulation is configured with a standard electrolyte storage unit and a metering regulation unit, and the replenishment amount is calculated according to the following formula:
[0066] ,in To replenish This refers to the total amount of electrolyte in the system. As the baseline concentration, For real-time concentration, The standard electrolyte concentration is set; the standard electrolyte is replenished at a precise rate through the metering and adjustment unit, with an adjustment accuracy of ±0.01mol / L, achieving concentration correction without stopping the machine. After replenishment is completed, the machine automatically stops and provides feedback on the status.
[0067] The safety protection execution unit can construct a three-level hierarchical protection logic, and combine leakage location and emergency cut-off functions to achieve full-scenario safety protection. It can handle faults according to their severity, and take into account fault warning, self-correction and emergency protection.
[0068] When the system control model operates at temperatures above 40°C, the circulation pump speed is increased to 120% of its rated speed. When T ≥ 45°C, the battery equalization interval is shortened to 45 minutes, and the charge / discharge current limit is reduced by 12% for every 5°C increase in temperature. When T ≥ 55°C, charging and discharging are suspended, with only heat dissipation and electrolyte circulation maintained. Charging and discharging are gradually resumed once T drops below 45°C.
[0069] The communication layer enables real-time data interaction between local layers, while also enabling remote data uploading, command issuance, and fault push to the cloud.
[0070] The power module is used to provide stable power to each level.
[0071] Furthermore, this invention takes a 10kW vanadium redox flow battery outdoor energy storage system as the application object, operates in a high-latitude outdoor environment of -30℃ to 60℃, has a total electrolyte volume of 20L, a rated capacity of 10kWh, a charge / discharge rate of 1C, and is implemented according to the steps of system construction, logic debugging, and actual working condition operation.
[0072] Example 1: System Setup and Logic Debugging
[0073] Hierarchical structure and logical configuration
[0074] According to the fully closed-loop management architecture described in this invention, the hardware construction and software logic configuration of the perception layer, control layer, execution layer, communication layer, and power module are completed. The core configuration requirements are as follows:
[0075] Sensing layer: Install each acquisition unit according to the global deployment logic, debug the acquisition frequency to 100Hz, calibrate the filter algorithm parameters (moving average window 10, median window 5), verify the acquisition accuracy and upload cycle of each parameter, and ensure that the voltage sampling delay is ≤45ms, the temperature measurement accuracy is ±0.4℃, and the electrolyte parameter acquisition accuracy meets the standards.
[0076] Control layer: Build a dual-core architecture of main controller and edge computing unit, load the software logic of three core control models, and preset core parameter thresholds; debug the multi-system linkage response delay to ensure ≤25ms; calibrate the temperature-concentration dual-factor correction formula, and verify the SOC estimation accuracy ≤±2.5% through simulation data.
[0077] Execution layer: Connects the execution units of charging and discharging, thermal management, electrolyte circulation, and safety protection. The action response time is ≤20ms. Verify the protection trigger logic, electrolyte concentration replenishment formula, and thermal management hierarchical control rules to ensure accurate execution of control commands and smooth closed-loop regulation.
[0078] Communication layer and power module: Build a dual-mode link for local CAN bus and remote wireless communication, debug local data transmission accuracy to 100% and remote communication latency ≤50ms; configure redundancy power supply logic for main and backup power supplies, verify that the main and backup power supply switching time is ≤10ms and the main power supply output fluctuation is ≤±0.45V at -30℃.
[0079] After completing the hardware setup and software configuration, the effectiveness and accuracy of the system's logic at each level were verified through simulated operating condition tests, covering four typical scenarios: low temperature, high temperature, abnormal electrolyte parameters, and safety protection. The verification results are as follows:
[0080] Low-temperature operation verification (-20℃): The system was started and the low-temperature linkage logic was triggered. After 30 minutes of preheating, the electrolyte temperature rose to 15℃. The charge and discharge rate gradually recovered from 0.2C to 1C. The SOC estimation error was 2.2%, which met the design requirements. There were no overcharge, over-discharge, or false alarms from the protection system.
[0081] High-temperature operating condition verification (50℃): The high-temperature synchronous control logic was triggered by simulating a high-temperature environment. After 15 minutes of heat dissipation, the electrolyte temperature dropped to 42℃. The system did not crash. The charging and discharging current grading limit was accurate. The electrolyte loss was reduced by 42% compared to the traditional BMS.
[0082] Electrolyte parameter anomaly verification: simulating scenarios of insufficient flow (1.8L / min), low concentration (1.18mol / L), and excessive pressure (0.6MPa), the system was able to accurately adjust the charge / discharge rate and cycle parameters according to the collaborative control model. The parameters all recovered to the threshold range within 10 minutes, and the charge / discharge rate increased steadily without impact damage.
[0083] Example 2: Actual Operating Conditions
[0084] The debugged BMS management system was applied to a 10kW vanadium redox flow battery outdoor energy storage system and operated continuously for 30 days, covering all operating conditions including low temperature (-30℃~-10℃), high temperature (45℃~60℃), normal temperature (20℃~30℃), and electrolyte circulation fluctuations. The core operating results are as follows:
[0085] Full-temperature range operation stability: In an environment of -30℃ to 60℃, the system has no downtime or false alarms, the protection command response delay is ≤28ms, the SOC estimation error is ≤±2.5%, the SOH estimation error is ≤±2.8%, and the accuracy of all acquired parameters meets the design requirements.
[0086] Multi-system collaborative control effect: The BMS, TMS and electrolyte circulation system are precisely linked, the low temperature preheating and charging and discharging synchronization is 100%, the high temperature heat dissipation response time is ≤1min, the electrolyte circulation efficiency is improved by 35%, and the high temperature electrolyte loss is reduced by 40% compared with the traditional BMS.
[0087] Safety and Operational Results: A total of 8 Level 1 warnings were triggered during operation, all of which were resolved through system self-correction, with no serious faults occurring; no shutdown was required for electrolyte concentration correction, reducing operation and maintenance costs by 40% compared to traditional solutions; the entire process of operation data is traceable, significantly improving the convenience of operation and maintenance.
[0088] Battery performance improvement: During the 30-day operation period, the voltage consistency of individual battery cells was good, with no local overcharging, over-discharging, or electrode corrosion. The charge and discharge efficiency remained stable at over 85%, which is 38% better than traditional BMS management. Based on this trend, the battery cycle life is expected to increase by more than 45%.
[0089] In summary, the flow battery BMS management system and method of the present invention can effectively solve the core technical defects of traditional BMS under complex operating conditions, realize high-precision status monitoring across the entire temperature range, and simultaneously coordinate and control the battery, electrolyte, and thermal management, provide safety protection, and enable emergency adjustment of the electrolyte without shutdown. This significantly improves the operating efficiency, safety, and cycle life of the flow battery, fully meets the core management and control requirements of distributed energy storage power stations and microgrid energy storage systems, and can be widely applied to energy storage scenarios such as vanadium redox flow batteries and zinc-bromine redox flow batteries.
[0090] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A BMS management system for a flow battery, comprising a sensing layer, a control layer, an execution layer, a communication layer, and a power module, characterized in that, The sensing layer is used to collect various parameters of the flow battery. The sensing layer includes a wide temperature range electrical parameter acquisition unit, a distributed temperature acquisition unit, an electrolyte circulation parameter acquisition unit, and a battery health status auxiliary acquisition unit. The control layer is the core processing unit of the system. It realizes accurate estimation of battery state, electrolyte circulation and charge-discharge control and issues precise control commands through built-in models. The built-in models of the control layer include a full-temperature-range state estimation model, an electrolyte circulation and charge-discharge control model and a system management model. The execution layer receives instructions from the control layer and performs actions such as charge / discharge regulation, thermal management, electrolyte circulation and concentration correction, and graded safety protection. The execution layer includes a high and low temperature resistant charge / discharge control unit, a thermal management execution unit, an electrolyte circulation regulation unit, and a safety protection execution unit. The communication layer enables real-time data interaction between local layers, and simultaneously completes remote data uploading, command issuance, and fault push with the cloud. The power module is used to provide stable power to each level.
2. The BMS management system for a flow battery according to claim 1, characterized in that, The wide-temperature-range electrical parameter acquisition unit is used to acquire current and voltage data of the flow battery. The distributed temperature acquisition unit is used to acquire temperature values of the battery stack, electrolyte storage tank, and circulation pipeline. Temperature acquisition points for the battery stack are located on each electrode, temperature acquisition points for the electrolyte storage tank are located at the top, middle, and bottom of the tank, and temperature acquisition points for the circulation pipeline are located at the inlet, outlet, and intermediate nodes of the pipeline. The spacing between intermediate nodes in the circulation pipeline is set to 4.5 cm, and the data from each acquisition point is filtered by the median value with a window size of 5. The electrolyte circulation parameter acquisition unit is used to acquire the flow rate, concentration, and pressure parameters of the electrolyte. The battery health status auxiliary acquisition unit uses a 1kHz high-frequency impedance method to acquire the internal resistance of the battery cells in real time, and the acquisition period is synchronized with the voltage acquisition.
3. The BMS management system for a flow battery according to claim 1, characterized in that, The full-temperature-range state estimation model achieves accurate SOC / SOH estimation by constructing a correction logic that couples temperature and electrolyte concentration parameters. The correction logic is as follows: For temperature correction factor , ,in For the electrolyte temperature, when T≤-10℃, a low-temperature compensation coefficient of 1.05 is added; when T≥45℃, a high-temperature compensation coefficient of 0.98 is added. For concentration correction factor ,in For the real-time concentration of the electrolyte, when <1.0 mol / L or When the concentration is >1.6 mol / L, a concentration compensation coefficient of 0.95 is applied. The closed-loop estimation method is as follows: ,in For the initial SOC, This is the charging and discharging current. For charging and discharging efficiency, To calibrate the SOC value twice every minute using the open-circuit voltage, based on the battery's rated capacity. SOH (State of Health) estimation integrates three parameters: cell internal resistance, cycle life, and capacity decay rate, taking into account the weighted impact of each parameter on battery health. The weighting is 4:3:3, and the specific quantitative estimation formula is as follows: in This represents the current internal resistance of a single battery cell. The internal resistance of a single cell in a brand-new battery state; This refers to the actual number of battery cycles. The rated number of battery cycles. For the battery's rated capacity, This represents the current actual capacity of the battery.
4. The BMS management system for a flow battery according to claim 1, characterized in that, The quantization matching rules for the electrolyte circulation and charge / discharge control model are as follows: The electrolyte flow rate and charge / discharge rate matching rules are as follows: When the flow rate is 2~3L / min, the rate limit is 0.2C~0.3C; when the flow rate is 3~5L / min, the rate limit is 0.3C~0.8C; when the flow rate is 5~8L / min, the rate limit is 0.8C~1.2C; when the flow rate is <2L / min or >8L / min, charging and discharging should be stopped immediately and the flow rate should be adjusted first. The electrolyte concentration and charge / discharge rate matching rules are as follows: At concentrations of 1.2–1.4 mol / L, full-rate charge / discharge at 1.2C is permissible; at concentrations of 1.0–1.2 mol / L or 1.4–1.5 mol / L, the rate is reduced by 30%; at concentrations <1.0 mol / L or >1.5 mol / L, concentration regulation is activated and the rate is reduced by 50%. In addition, when the electrolyte pressure exceeds the threshold of 0.1~0.5MPa, the flow rate is adjusted by adjusting the speed of the circulating pump. If the pressure is too high, the flow rate is reduced; if the pressure is too low, the flow rate is increased. The charging and discharging current is adjusted simultaneously.
5. The BMS management system for a flow battery according to claim 1, characterized in that, When the temperature is below -5℃, the system control model starts the preheating unit and the circulating pump runs at 30% of its rated speed. When the temperature rises to 5℃, the power of the preheating unit is reduced to 50%. When the temperature rises to 15℃, the preheating unit is shut down and the circulating pump returns to its rated speed, allowing low-rate charging and discharging at 0.2C. After the temperature stabilizes above 15℃ for 30 minutes, the normal charging and discharging rate is restored.
6. The BMS management system for a flow battery according to claim 1, characterized in that, When the temperature is above 40°C, the circulating pump speed is increased to 120% of the rated speed. When T≥45°C, the battery equalization interval is shortened to 45 minutes, and the charging and discharging current limit is reduced by 12% for every 5°C increase. When T≥55°C, charging and discharging are suspended, and only heat dissipation and electrolyte circulation are maintained. Charging and discharging are gradually resumed after T drops below 45°C.
7. A management method for a BMS management system of a flow battery as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. System initialization and parameter preset: After the system starts, it completes self-test of power supply and communication links at each level, loads preset parameter thresholds in the control layer, and enters standby mode in the execution layer. If the self-test fails, an early warning is triggered and the fault is located. S2. Real-time acquisition and preprocessing of all parameters: The sensing layer synchronously acquires electrical parameters, temperature, electrolyte circulation parameters, and monomer internal resistance at a frequency of 100Hz, judges the validity of the data in real time, performs moving average filtering or median filtering preprocessing on the acquired data, and uploads the preprocessed data to the control layer at a period of 10ms. S3. Accurate estimation of battery state across the entire temperature range: The control layer inputs preprocessed data into the full-temperature-range state estimation model and dynamically estimates SOC / SOH through temperature and concentration dual-factor coupling correction logic. SOC is calibrated twice every minute and SOH is updated once every hour. S4. Electrolyte circulation and charge / discharge control: The control layer compares the electrolyte parameters with the preset threshold and adjusts the charge / discharge rate and circulation pump speed and flow rate through a collaborative control model. After the parameters are restored to the threshold range, the normal rate is gradually restored, forming a closed-loop regulation. S5. System management: The control layer triggers the low-temperature or high-temperature control logic of the system management model based on the electrolyte and battery stack temperatures, enabling real-time synchronous monitoring of the BMS, TMS, and electrolyte circulation system until the temperature returns to the normal range. S6. Safety protection: The control layer monitors the system operating parameters in real time, triggers corresponding protection based on the degree of parameter deviation from the threshold, and resets the system according to the corresponding rules after the fault is cleared. S7. Data storage and remote debugging: The control layer stores the entire process data locally. The original acquired data is retained for 30 days, the SOC / SOH estimation results are retained for 90 days, and the control commands and protection action records are permanently retained. It supports real-time parameter viewing on the cloud platform, remote modification of preset thresholds, and fault location by reading operation logs.
8. The BMS management method for a flow battery according to claim 7, characterized in that, The preset core parameter thresholds mentioned in step S1 are: electrolyte flow rate 2~8L / min, concentration 1.2~1.4mol / L, pressure 0.1~0.5MPa; low temperature preheating threshold ≤-5℃, high temperature heat dissipation threshold ≥40℃; charging cut-off voltage 1.6V / cell, discharging cut-off voltage 0.85V / cell.
9. The BMS management method for a flow battery according to claim 7, characterized in that, The filtering rules in step S2 are as follows: voltage and current are filtered using a moving average with a window size of 10, and temperature and electrolyte concentration are filtered using a median value with a window size of 5 to eliminate instantaneous interference.