A high-precision soc monitoring flow battery based on dynamic voltage sampling

Abstract

The utility model relates to the technical field of liquid flow battery discloses a kind of high-precision SOC monitoring liquid flow battery based on dynamic voltage sampling, including one or several small electric piles, each small electric pile includes fixed plate, insulating plate, copper plate, liquid inlet plate, carbon felt, sealing membrane, bipolar plate, sealing membrane, carbon felt, flow channel plate and ion membrane sealing membrane arranged symmetrically from outside to inside, fixed plate, insulating plate, copper plate, liquid inlet plate, sealing membrane, bipolar plate are provided with at least two flow channel holes, wherein ion membrane is provided between adjacent ion membrane sealing membrane;Voltage sampling circuit is provided on the copper plate;The voltage sampling circuit includes voltage dividing circuit, filter circuit, limiting amplitude circuit and operational amplifier, for voltage dividing, protection, filtering and isolation treatment to the electric liquid of small electric pile two ends, and output standardized signal. By setting specific voltage sampling circuit, the electric liquid of small electric pile two ends is voltage divided, protected, filtered and isolated, which helps to realize the high-precision measurement of liquid flow battery SOC.

Description

Technical Field

[0001] This utility model relates to the field of flow battery technology, and in particular to a high-precision SOC monitoring flow battery based on dynamic voltage sampling. Background Technology

[0002] In the full lifecycle management system of flow batteries, accurate monitoring of the State of Charge (SOC) is a core element for achieving efficient system operation and safe management. Currently, the industry commonly uses an SOC calculation model based on the electrolyte open-circuit voltage (OCV), which relies on sub-millisecond response speed and microvolt-level resolution voltage sampling technology. Due to the strong coupling between the electrolyte's dynamic characteristics and the electrochemical system, any delay or error in the sampling process will lead to SOC estimation deviations, subsequently triggering a chain reaction of problems such as power imbalance and capacity decay.

[0003] Existing sampling schemes mostly follow the traditional contact-based technical architecture: the front end uses a wedge-shaped electrical clamp as the physical coupling element at the electrode-electrolyte interface, and the back end is equipped with a non-common-ground circuit unit to implement isolated voltage sampling. The flow channel design of this type of clamp has a structural defect—its narrowed-diameter liquid path structure generates fluid resistance as high as 80-120 mPa·s. When the electrolyte circulation flow rate exceeds 5L / min, a significant concentration polarization layer is formed, causing the sampling point potential to lag behind the actual value by 150-300ms. At the circuit level, conventional isolated sampling schemes require multi-stage operational amplifier isolators and optocoupler modules, with a single-channel hardware cost exceeding 200 yuan. Furthermore, limited by the bandwidth bottleneck of ±0.1% accuracy operational amplifiers, it is difficult to capture high-frequency voltage fluctuations during battery charging and discharging.

[0004] As organic flow batteries evolve towards MW-level energy storage power stations, their electrolyte circulation flow rate has exceeded 30L / min, and system voltage monitoring needs to simultaneously meet the stringent requirements of 0.1% accuracy and 100kHz sampling rate. The dual bottlenecks of existing technologies at the fluid dynamics and signal processing levels have become key obstacles restricting the intelligent upgrade of flow battery energy management systems (EMS). Utility Model Content

[0005] To address existing problems, this invention provides a high-precision SOC monitoring system for flow batteries based on dynamic voltage sampling. Through innovative design of a single-chip small stack structure and optimized voltage sampling circuitry, voltage division, filtering, limiting, and isolation are performed to provide a low-latency data acquisition unit with mPa-level fluid resistance and a current flow capacity of 50L / min. It is equipped with a low-cost, high-precision sampling scheme based on digital isolation and Σ-Δ modulation technology to solve the problems of high sampling delay, high cost, and insufficient accuracy in flow battery SOC monitoring.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] A high-precision SOC monitoring flow battery based on dynamic voltage sampling includes one or more small stacks. Each small stack includes a fixed plate, an insulating plate, a copper plate, a liquid inlet plate, a carbon felt, a sealing membrane, a bipolar plate, a flow channel plate, and an ion membrane sealing membrane, arranged symmetrically from the outside to the inside. The fixed plate, insulating plate, copper plate, liquid inlet plate, sealing membrane, and bipolar plate are all provided with at least two flow channel holes. An ion membrane is provided between adjacent ion membrane sealing membranes. A voltage sampling circuit is provided on the copper plate. The voltage sampling circuit includes a voltage divider circuit, a filter circuit, a limiting circuit, and an operational amplifier, which are used to perform voltage division, protection, filtering, and isolation processing on the electro-hydraulic components at both ends of the small stack, and output a standardized signal.

[0008] As a further improvement of this utility model, the filtering circuit includes a first filtering circuit and a second filtering circuit; the limiting circuit includes a first limiting circuit and a second limiting circuit; the non-inverting input terminal of the operational amplifier is connected to the voltage divider circuit, the first filtering circuit, and the first limiting circuit respectively; the inverting input terminal and the output terminal of the operational amplifier are both connected to the second filtering circuit; and the inverting input terminal and the output terminal of the operational amplifier are both connected to the second limiting circuit.

[0009] As a further improvement of this utility model, the input and output terminals of the voltage sampling circuit are led out on the copper plate, which are used for inputting and outputting sampling signals, respectively.

[0010] As a further improvement of this utility model, the voltage divider circuit uses a metal film resistor with an accuracy of ±0.1% and a temperature drift of 5ppm / ℃.

[0011] As a further improvement of this invention, the offset voltage of the operational amplifier is ≤15μV.

[0012] As a further improvement of this utility model, the filter circuit uses ceramic capacitors.

[0013] As a further improvement of this utility model, the ion membrane is a cation membrane or an anion membrane.

[0014] As a further improvement of this utility model, the flow channel plate is made of double-layer PP board, with a serpentine flow channel carved on the lower layer and through holes opened on the upper layer.

[0015] As a further improvement of this utility model, the sealing film is made of PVC soft film.

[0016] As a further improvement of this utility model, a hot-melt pressing area is reserved at the edge of the sealing film.

[0017] This utility model has the following beneficial effects: By setting up a specific voltage sampling circuit (including voltage divider, filter, limiter circuit and operational amplifier), the electro-hydraulic components at both ends of the small battery stack are subjected to voltage divider, protection, filtering and isolation processing and a standardized signal is output, which helps to achieve high-precision measurement of the state of charge (SOC) of the flow battery.

[0018] Preferably, the filtering circuit is divided into a first filtering circuit and a second filtering circuit, and the limiting circuit is divided into a first limiting circuit and a second limiting circuit. The connection method between the operational amplifier and each circuit is clearly defined, which can optimize the signal processing flow, make the filtering and limiting effects more accurate, further improve the accuracy and stability of signal processing, and thus achieve more accurate SOC measurement.

[0019] Preferably, the input and output terminals of the voltage sampling circuit are led out on the copper plate to ensure the transmission of the sampling signal, making the acquisition and transmission of the signal more convenient and efficient, which is conducive to accurately obtaining battery-related information to achieve high-precision SOC measurement.

[0020] Preferably, the voltage divider circuit uses a metal film resistor with an accuracy of ±0.1% and a temperature drift of 5ppm / ℃ to provide a more accurate voltage divider signal, thereby improving the accuracy of voltage sampling, reducing errors caused by resistor accuracy and temperature drift, and thus improving the accuracy of SOC measurement.

[0021] Preferably, the offset voltage of the operational amplifier is ≤15μV, which can reduce the impact of the operational amplifier's own performance on signal processing, reduce errors in the signal processing process, ensure the accuracy of signal processing, and help to achieve high-precision SOC measurement.

[0022] Preferably, the filter circuit uses ceramic capacitors, which have stable electrical performance and can effectively filter out interference components in the signal, improve signal quality, and thus provide a more reliable signal for accurate SOC measurement.

[0023] Preferably, the ion exchange membrane is either a cation exchange membrane or an anion exchange membrane. The appropriate ion exchange membrane can be selected according to the specific working requirements and ion transport characteristics of the battery, so as to ensure effective ion transport, reduce adverse reactions, maintain a stable internal environment of the battery, and provide stable conditions for accurate measurement of SOC.

[0024] Preferably, the flow channel plate is made of double-layer PP board, with the lower layer engraved with serpentine flow channels and the upper layer having through holes. This structure can optimize the flow of electrolyte in the flow channel plate, making the electrolyte distribution more uniform, improving the battery reaction efficiency, and providing a more stable battery performance basis for accurate measurement of SOC.

[0025] Preferably, the sealing film is made of PVC soft film. PVC soft film has a certain degree of flexibility and sealing performance, which can better fit the internal structure of the battery, effectively prevent electrolyte leakage, ensure the safe and stable operation of the battery, and facilitate accurate measurement of SOC.

[0026] Optionally, a hot-melt bonding area is reserved at the edge of the sealing film to facilitate a tight connection between the sealing film and other battery components through the hot-melt bonding process, thereby enhancing the sealing effect, preventing electrolyte leakage, and ensuring stable battery operation and accurate SOC measurement. Attached Figure Description

[0027] The accompanying drawings described herein are for illustrative purposes only and do not limit the scope of this invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a structural diagram of a high-precision SOC monitoring flow battery based on dynamic voltage sampling as described in Example 1; Figure 2 This is a front view of the flow channel plate of a high-precision SOC monitoring flow battery based on dynamic voltage sampling as described in Example 1; Figure 3 This is a schematic diagram of a voltage sampling circuit for a high-precision SOC monitoring flow battery based on dynamic voltage sampling, as described in Example 1. The components are as follows: 1. Fixing plate; 2. Insulating plate; 3. Copper plate; 4. Liquid inlet plate; 5. Carbon felt; 6. Sealing membrane; 7. Bipolar plate; 8. Flow channel plate; 9. Ion membrane; 10. Ion membrane sealing membrane; 11. First support surface; 12. Liquid inlet; 13. Reaction zone; 14. Second support surface; 15. Sealing surface; 16. Liquid outlet; 17. Screw hole. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0029] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0030] Unless otherwise defined below, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Example 1 like Figure 1 As shown, a high-precision SOC monitoring flow battery based on dynamic voltage sampling includes one or more small stacks. Each small stack includes a fixed plate 1, an insulating plate 2, a copper plate 3, a liquid inlet plate 4, a carbon felt 5, a sealing membrane 6, a bipolar plate 7, a flow channel plate 8, and an ion membrane sealing membrane 10, arranged symmetrically from the outside to the inside. The fixed plate 1, insulating plate 2, copper plate 3, liquid inlet plate 4, sealing membrane 6, and bipolar plate 7 are each provided with at least two flow channel holes. An ion membrane 9 is provided between adjacent ion membrane sealing membranes 10. A voltage sampling circuit is provided on the copper plate 3.

[0032] Specifically, the single-cell battery stack, as the core component of the system, has all its parts working together to ensure efficient electrolyte flow. The single-cell battery stack includes a fixing plate 1, battery cells, inlet and outlet ports, and fixing screws. The fixing plate 1 is made of 10mm thick iron plate, a material that not only has sufficient strength to support the entire battery cell but is also relatively economical and suitable for large-scale applications. The battery cell is composed of a copper plate 3, an inlet plate 4, carbon felt 5, a sealing membrane 6, a bipolar plate 7, a flow channel plate 8, an ion exchange membrane sealing membrane 10, and an ion exchange membrane 9. The flow channel plate 8 adopts a unique double-layer PP board structure. The lower layer is engraved with partition-type flow channels. This flow channel design can effectively guide the electrolyte to flow to the ion membrane 9, ensuring full contact between the electrolyte and the ion membrane 9 and improving the reaction rate. The upper layer is provided with through holes, which coincide with the holes on the bipolar plate 7, sealing membrane 6, and liquid inlet plate 4, thereby achieving smooth connection of the liquid path and reducing resistance during the liquid flow process. The sealing membrane 6 is made of 0.4mm thick PPO soft film. This material has good sealing and flexibility, and can tightly fit various components to prevent electrolyte leakage. At the same time, its thickness is moderate and will not cause additional obstruction to the liquid flow. The ion membrane 9 can be either a cation membrane 9 or an anion membrane 9 to meet the working requirements of different types of flow batteries. The liquid inlet plate 4 is located between the copper plate 3 and the sealing membrane 6, which plays an important role in fixing the position of various components of the battery unit and maintaining the stability of the entire battery unit structure. The liquid inlet and outlet holes pass through the fixing plate 1 and are connected to the battery power supply to realize the coordinated work of the liquid path and the circuit. Screws reinforce the connection of the two fixing plates 1, so that the entire monolithic small stack forms a compact and stable whole. This optimized structural design effectively reduces flow channel resistance and scientifically plans the electrolyte exchange path, ensuring that there is no significant delay even when the electrolyte flow rate reaches 50 L / min, thus guaranteeing the continuity and stability of the flow battery operation.

[0033] The voltage sampling circuit includes a voltage divider circuit, a filter circuit, a limiting circuit, and an operational amplifier. It is used to perform voltage division, protection, filtering, and isolation processing on the electrohydraulic circuit at both ends of the small fuel cell stack, and output a standardized signal. The input and output terminals of the voltage sampling circuit are led out from the copper plate 3, used for inputting and outputting the sampling signal, respectively. The filter circuit includes a first filter circuit and a second filter circuit; the limiting circuit includes a first limiting circuit and a second limiting circuit; the non-inverting input terminal of the operational amplifier is connected to the voltage divider circuit, the first filter circuit, and the first limiting circuit, respectively; the inverting input terminal and output terminal of the operational amplifier are both connected to the second filter circuit; and the inverting input terminal and output terminal of the operational amplifier are both connected to the second limiting circuit.

[0034] Specifically, such as Figure 3As shown, the high-precision voltage sampling circuit consists of voltage divider sampling, voltage protection, power supply filtering, signal isolation and tracking, and low-voltage filtering modules. In the voltage sampling circuit, one end of resistor R1 is connected to the input signal VIN, and the other end is simultaneously connected to the positive terminal of diode D1, one end of resistor R2, one end of capacitor C1, and pin 5 (non-inverting input) of operational amplifier U1B. Resistor R2 is connected in series with resistors R3 and R4, and one end of resistor R4 is grounded. Thus, resistors R1, R2, R3, and R4 form a voltage divider circuit, which can reasonably divide the input signal VIN. The other end of diode D1 is connected to the 11V voltage, playing a crucial role in voltage protection. When the voltage after voltage division is greater than 11V, the diode conducts, and current flows to the 11V power supply, thereby preventing excessively high voltage from flowing to subsequent circuits and protecting the safety of subsequent components. When the voltage after voltage division is less than 11V, the diode is cut off, and current flows to subsequent circuits, ensuring normal circuit operation. The other end of capacitor C1 is grounded, serving as a filter to effectively remove noise, glitches, and other interference from the input signal. Pin 6 and pin 7 (output) of op-amp U1B are connected to resistor R5 to form a voltage follower circuit. This circuit design ensures that the input voltage at pin 5 matches the output voltage at pin 7, while also providing isolation to further filter interference and improve signal stability. The other end of resistor R5 is connected to the anode of diode D2 and one end of capacitor C2. The cathode of diode D2 is connected to 3.3V, and the other end of capacitor C2 is connected to GND. Diode D2 and capacitor C2 form a low-pass filter circuit. This circuit limits the output voltage to 3.3V, further protecting subsequent circuits from damage due to excessive voltage. The low-pass filter also effectively removes high-frequency noise, resulting in a smoother output signal.

[0035] The voltage divider circuit uses a metal film resistor with an accuracy of ±0.1% and a temperature drift of 5ppm / ℃.

[0036] The offset voltage of the operational amplifier is ≤15μV.

[0037] The filter circuit uses ceramic capacitors.

[0038] The ion exchange membrane 9 is either a cation exchange membrane 9 or an anion exchange membrane 9.

[0039] The flow channel plate 8 is made of double-layer PP board, with a serpentine flow channel carved on the lower layer and through holes opened on the upper layer.

[0040] The sealing membrane 6 is made of PVC soft film.

[0041] The sealing film 6 has a pre-reserved hot-melt pressing area at its edge.

[0042] The bipolar plate 7 serves as the "carrier and conduction hub" for electrochemical reactions. Firstly, it acts as the structural framework of the battery stack, separating the electrolyte channels of adjacent individual cells and preventing mixing of the positive and negative electrolytes. Secondly, it serves as a current conduction channel, efficiently conducting electrons generated by redox reactions on the electrode surface (such as carbon paper or carbon cloth) to the external circuit (or receiving electrons from the external circuit). Thirdly, it provides a "signal transmission interface" for the OCV clamp. The electrolyte turnover rate in the OCV clamp affects the SOC detection speed of the battery system, so the OCV clamp must have low flow resistance. To accommodate the sealing balls at the inlet / outlet ports 16, several inlet / outlet holes are provided on the bipolar plate 7, along with multiple support surfaces. Figure 2 As shown, the flow channel plate 8 adopts a symmetrical design to ensure balanced fluid flow and pressure on both sides, avoiding local overheating / overcooling or uneven filling. The flow channel plate 8 is provided with a first support surface 11, an inlet 12, a reaction zone 13, a second support surface 14, a sealing surface 15, an outlet 16, and screw holes 17. When the electrolyte flows through the inlet 12, it flows along the spokes on the surface of the flow channel plate 8 to the surrounding area, and then is guided along the arc-shaped sealing surface 15 to the rows of second support surfaces 14, forming several thin streams flowing towards the reaction zone 13. The electrolyte passing through the reaction zone 13 then sequentially passes through the second support surface 14 and the sealing surface 15 on the other side to the outlet 16. This flow channel design helps to disperse the cross-sectional area of ​​the liquid flow, reduce viscosity, and increase flow rate.

[0043] The principle behind achieving high-precision voltage detection in this embodiment is as follows: First, the single-chip miniature stack is connected in parallel with the electrolyte main circuit of the flow battery. This connection method can utilize the equivalent valence state of the electrolyte in the single-chip miniature stack to collect the SOC voltage. Since the structure of the single-chip miniature stack is optimized, it can quickly respond to changes in the electrolyte, thereby ensuring that the collected voltage signal can truly reflect the actual SOC state of the flow battery. Secondly, the acquired voltage signal undergoes a series of processing steps by a matching voltage sampling circuit. The circuit first divides the signal, converting the high-voltage signal into a low-voltage signal suitable for subsequent processing. Next, voltage protection is implemented to prevent damage from excessive voltage. Then, power supply filtering and low-voltage filtering are performed to remove various interference noises from the signal. Simultaneously, a signal isolation and follower module ensures stable signal transmission and isolation, ultimately outputting a standardized signal V0*K2 (where K2=0.98) to the subsequent system. The subsequent system can then perform further analysis and processing based on this standardized signal to calculate the SOC value of the flow battery. Finally, through precise matching of hardware parameters and coordinated circuit design, the entire voltage detection system achieves high-performance monitoring indicators with a sampling delay of ≤10ms and an accuracy of ±0.1%. Matching hardware parameters ensures that each component in the circuit operates at its optimal state, reducing errors caused by parameter mismatches; coordinated circuit design ensures efficient cooperation between modules, jointly improving the overall system performance. This technological innovation not only compresses the sampling delay to within 10ms, narrowing the SOC estimation error from the current ±5% to ±1.5%, but also reduces the cost per channel by more than 60% through integrated design, laying a technological foundation for building high-performance, cost-effective flow battery energy storage systems.

[0044] Example 2 The specific configuration of the voltage sampling circuit in this embodiment is as follows: Voltage divider circuit: Select metal film resistors (R1=20Ω, R2=R3=R4=360Ω) with an accuracy of ±0.1% and a temperature drift of 5ppm / ℃, and divide the voltage according to the ratio of K2=0.98.

[0045] Protection and filtering module: Voltage clamping: D1 uses 1N4741A (11V Zener diode), and D2 uses BAS16 hermetically sealed Schottky diode (3.3V clamping). Filtering network: C1 and C2 are 0.1μF ceramic capacitors, which, together with op-amp U1B (AD8605, offset voltage ≤15μV), form a second-order low-pass filter with a cutoff frequency of 10kHz.

[0046] The assembly process of the flow battery in this embodiment is as follows: Component preparation: Fixing plate 1: Cut a 10mm thick iron plate and make mounting holes and liquid inlet / outlet holes that match the battery unit; Flow channel plate 8: Made of double-layer PP board, the lower layer is engraved with a serpentine flow channel with a depth of 1.5mm and a width of 2mm, and the upper layer has a through hole with a diameter of 5mm; Sealing film 6: Cut 0.8mm PVC soft film, leaving a hot melt pressing area at the edge.

[0047] Assembly steps: Stack the plates in the following order: "Fixed plate 1 - Insulating plate 2 - Copper plate 3 - Liquid inlet plate 4 - Carbon felt 5 - Sealing membrane 6 - Bipolar plate 7 - Sealing membrane 6 - Carbon felt 5 - Flow channel plate 8 - Ion membrane sealing membrane 10 - Ion membrane 9 - Ion membrane sealing membrane 10 - Flow channel plate 8 - Carbon felt 5 - Sealing membrane 6 - Bipolar plate 7 - Sealing membrane 6 - Carbon felt 5 - Liquid outlet plate - Copper plate 3 - Insulating plate 2 - Fixed plate 1". Tighten the plates with fixing screws to a torque of 8 N•m to ensure good sealing of the liquid circuit and good electrical contact.

[0048] The system testing process is as follows: Connect the inlet and outlet ports of the small fuel cell stack to the electrolyte circulation pipeline in parallel with quick-connect couplings to ensure flow rate matching. The input terminal of the voltage sampling circuit is soldered to the lead electrode of copper plate 3 of the small fuel cell stack, and the output terminal is connected to the data acquisition card. Tests were conducted in the flow rate range of 5-30 L / min, verifying a sampling delay of <10 ms; the measured accuracy reached ±0.08% when the signal was injected through a standard voltage source, meeting the design requirements.

[0049] Advantages of this utility model: This invention, through dual innovation in structure and circuitry, reduces hardware costs by 60% while significantly improving the real-time performance and accuracy of flow battery SOC monitoring. It is low-cost and suitable for large-scale energy storage system applications.

[0050] The monolithic miniature stack is a self-made device, small in size and simple in structure, with no electronic components, high reliability, and low price. The sampling circuit uses only one differential operational amplifier, with few components, high reliability, and low price.

[0051] The above embodiments are merely one of the implementation methods for achieving the technical solution of this utility model. The scope of protection claimed by this utility model is not limited to this embodiment, but also includes any variations, substitutions, and other implementation methods that are easily conceived by those skilled in the art within the scope of the technology disclosed in this utility model. Although embodiments of this utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model. The scope of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high-precision SOC monitoring flow battery based on dynamic voltage sampling, characterized in that, It includes one or more small electric stacks. Each small electric stack includes a fixed plate (1), an insulating plate (2), a copper plate (3), a liquid inlet plate (4), a carbon felt (5), a sealing membrane (6), a bipolar plate (7), a flow channel plate (8), and an ion membrane sealing membrane (10) arranged symmetrically from the outside to the inside. The fixed plate (1), the insulating plate (2), the copper plate (3), the liquid inlet plate (4), the sealing membrane (6), and the bipolar plate (7) are all provided with at least two flow channel holes. An ion membrane (9) is provided between adjacent ion membrane sealing membranes (10). A voltage sampling circuit is provided on the copper plate (3). The voltage sampling circuit includes a voltage divider circuit, a filter circuit, a limiting circuit, and an operational amplifier, which are used to perform voltage division, protection, filtering, and isolation processing on the electro-hydraulic fluid at both ends of the small electric stack, and output a standardized signal.

2. The high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The filtering circuit includes a first filtering circuit and a second filtering circuit; the limiting circuit includes a first limiting circuit and a second limiting circuit; the non-inverting input terminal of the operational amplifier is connected to the voltage divider circuit, the first filtering circuit, and the first limiting circuit respectively; the inverting input terminal and the output terminal of the operational amplifier are both connected to the second filtering circuit; and the inverting input terminal and the output terminal of the operational amplifier are both connected to the second limiting circuit.

3. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The input and output terminals of the voltage sampling circuit are led out from the copper plate (3) and used to input and output sampling signals, respectively.

4. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The voltage divider circuit uses a metal film resistor with an accuracy of ±0.1% and a temperature drift of 5ppm / ℃.

5. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The offset voltage of the operational amplifier is ≤15μV.

6. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The filter circuit uses ceramic capacitors.

7. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The ion membrane (9) is a cation membrane or an anion membrane.

8. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The flow channel plate (8) is made of double-layer PP board, with a serpentine flow channel carved on the lower layer and through holes opened on the upper layer.

9. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 1, characterized in that, The sealing membrane (6) is made of PVC soft film.

10. A high-precision SOC monitoring flow battery based on dynamic voltage sampling according to claim 9, characterized in that, The sealing film (6) has a reserved hot-melt pressing area at its edge.

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