Electrolyte charge state detection device and method for liquid flow energy storage system

Abstract

The invention relates to the technical field of battery performance detection, and provides an electrolyte state-of-charge detection device and method for a liquid flow energy storage system, and the device comprises a pair of battery end plates and at least one pair of bipolar plates which are made of a conductive material and are arranged between the battery end plates; each bipolar plate is connected with a detection terminal used for collecting an open-circuit voltage signal established through the electrolyte; an ion conduction membrane is arranged between the two bipolar plates, and the ion conduction membrane and the two sides form a circulation cavity for accommodating electrolyte; a to-be-measured positive electrode electrolyte and a to-be-measured negative electrode electrolyte are respectively introduced into the circulation cavities at the two sides of the ion conduction membrane, and a potential difference is formed at the two sides of the ion conduction membrane. According to the invention, a stable open-circuit potential is established under the conditions of no current passing and no external electrode reaction, and the bipolar plate is used as a potential acquisition end, is connected to a voltage detection terminal and does not participate in an oxidation-reduction reaction, so that the detection process is ensured to be in an electrochemical static state, and high-precision online monitoring of the SOC of the electrolyte is realized.

Description

Technical Field

[0001] This invention relates to the technical field of electrolyte state performance testing, specifically to a device and method for detecting the state of charge of electrolyte in a liquid flow energy storage system. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Redox flow batteries (RBBs) are a type of renewable energy storage technology that utilizes the reversible redox reaction of active species in an electrolyte to convert electrical energy into chemical energy. They offer advantages such as long lifespan, intrinsic safety, and independent controllability of power and capacity. Vanadium redox flow batteries (VRFBs) use electrolytes composed of vanadium ions in different valence states at their positive and negative electrodes, which are pumped through the reaction zone of the stack to achieve the charging and discharging process. The state of charge (SOC) of a flow battery represents the ratio of oxidized to reduced active species in the electrolyte, directly affecting the battery's current system operating state, charging status, and remaining discharge capacity. It is a core parameter for the scheduling and control of the battery management system (BMS). Unlike traditional lithium-ion batteries, the SOC of a flow battery is determined by the concentration of active species in the electrolyte; and because polarization occurs during the electrochemical reaction, the SOC cannot be directly measured from the voltage or current of a single cell. It must be indirectly detected by monitoring the electrolyte SOC during an electrochemical process.

[0004] The inventors discovered in their research that existing flow battery system SOC detection devices mainly employ a traditional single-cell structure, using carbon felt electrodes or similar electrode structures to estimate SOC by measuring electrode potential or stack-end voltage. This approach suffers from the following technical problems: First, graphite carbon felt is typically used as the electrode in SOC detection devices. However, the graphite felt fibers and micro-gaps easily absorb electrolyte, leading to uneven flow velocity within the electrode and local concentration polarization. This causes a lag between the electrode surface concentration and the bulk solution concentration at the data acquisition point, resulting in delayed SOC response and decreased accuracy. Second, hydrogen evolution side reactions easily occur on the negative electrode side of the carbon felt electrode, making the measured potential a mixture of redox reactions and hydrogen evolution side reactions, interfering with accurate SOC calculation. Third, the uneven distribution of electrolyte flow velocity within the electrodes in traditional battery stacks easily leads to local concentration polarization, further reducing the stability of potential measurements. These problems make it difficult for SOC estimation methods based on conventional electrode structures to meet the real-time management requirements of large-scale flow battery energy storage systems. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a device and method for detecting the state of charge (SOC) of an electrolyte in a flow energy storage system. This method establishes a stable open-circuit potential under conditions of no current flow and no external electrode reaction. Bipolar plates, acting as potential acquisition terminals, are connected to voltage detection terminals and do not participate in redox reactions, thus ensuring that the detection process is in an electrochemically static state, achieving high-precision, real-time online monitoring of the electrolyte's SOC.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: One or more embodiments provide an electrolyte state of charge detection device for a flow energy storage system, comprising: A pair of battery end plates are used to provide mechanical clamping force and serve as a fixed housing structure; At least one pair of bipolar plates, made of conductive material, are disposed between the battery end plates; each bipolar plate is connected to a detection terminal for acquiring the open-circuit voltage signal established through the electrolyte; An ion-conducting membrane is placed between two bipolar plates, and a support frame with a set thickness is placed between the ion-conducting membrane and the bipolar plates on both sides. The ion-conducting membrane forms a flow cavity for containing electrolyte between the support frame and the bipolar plates on both sides. The positive and negative electrolytes to be tested are respectively introduced into the flow cavities on both sides of the ion-conducting membrane, and a potential difference is formed on both sides of the ion-conducting membrane.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: This implementation eliminates the need for traditional carbon felt electrodes, thus avoiding concentration polarization and response hysteresis caused by liquid absorption through pores, effectively improving the immediacy and accuracy of potential measurement. The electrodeless reaction structure avoids interference from the hydrogen evolution side reaction at the negative electrode, improving the reliability of SOC estimation. The diffusion control system constructed through the ion conduction membrane makes the detection structure more stable and repeatable, making it suitable for continuous online electrolyte SOC monitoring in large-scale flow energy storage systems. The advantages of the present invention, as well as its additional advantages, will be described in detail in the following specific embodiments. Attached Figure Description

[0008] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0009] Figure 1 This is a schematic diagram of the SOC detection device according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the flow channel structure of the flow cavity on the bipolar plate in Embodiment 1 of the present invention; Figure 3 This is a first cross-sectional view of a portion of the SOC detection device of Embodiment 1 of the present invention after assembly without the flow channel structure. Figure 4 This is a second cross-sectional view of the SOC detection device of Embodiment 1 of the present invention after the assembly of a portion of the device and the setting of the flow channel structure; The components are: 1. Battery end plate; 2. Bipolar plate; 3. Support frame; 4. Ion conduction membrane; 21. Liquid inlet; 22. Liquid outlet; 23. Straight flow channel. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, 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.

[0012] It should be noted that the terminology used herein is for describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. It should be noted that, without conflict, the various embodiments and features within those embodiments can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0013] Example 1 In one or more of the technical solutions disclosed in the embodiments, such as Figures 1 to 2 As shown, an electrolyte state-of-charge detection device for a fluid energy storage system includes: A pair of battery end plates 1 are used to provide mechanical clamping force and serve as a fixed housing structure; At least one pair of bipolar plates 2, made of conductive material, are disposed between the battery end plates; each bipolar plate 2 is connected to a voltage detection terminal for acquiring the open-circuit voltage signal established by the electrolyte; An ion-conducting membrane 4 is disposed between two bipolar plates 2. A support frame 3 with a set thickness is disposed between the ion-conducting membrane 4 and the bipolar plates 2 on both sides. The ion-conducting membrane 4 forms a flow cavity for containing electrolyte between the support frame 3 and the bipolar plates 2 on both sides. The positive electrolyte and negative electrolyte to be tested are respectively introduced into the flow cavity on both sides of the ion-conducting membrane 4, and a potential difference is formed on both sides of the ion-conducting membrane 4.

[0014] In this embodiment, the SOC detection device utilizes the diffusion equilibrium process of the electrolyte across the ion-conducting membrane to establish a stable open-circuit potential under conditions of no current flow and no external electrode reaction. The bipolar plate 2, acting as a potential acquisition terminal, is connected to the voltage detection terminal and does not participate in the redox reaction, ensuring the electrochemical static conditions of the detection process. When measuring the SOC of the electrolyte, flow chambers for containing the electrolyte are formed on both sides of the ion-conducting membrane 4. The positive electrolyte flows into one flow chamber of the ion-conducting membrane 4, and the negative electrolyte flows into the other flow chamber. This achieves selective ion migration channels provided by the ion-conducting membrane 4, controlling the distribution of ions in different redox states on both sides of the ion-conducting membrane 4, thereby establishing a potential difference between the electrolyte component concentration and the positive and negative electrolytes. By measuring this open-circuit potential, the redox equilibrium state of the electrolyte can be indirectly reflected, thus estimating its SOC level. The support frame 3 is used to limit the thickness of the flow chamber between the membrane and the bipolar plate, ensuring a stable diffusion environment for the electrolyte within the flow chamber. Optionally, the thickness of the support frame 3 can be in the range of 0.1mm to 50mm. Different flow channel structures can be adopted according to different support frame 3 thicknesses. Thinner support frames of 0.1mm to 2mm need to be equipped with flow channel structures to increase electrolyte flow and improve detection timeliness.

[0015] This implementation eliminates the need for traditional carbon felt electrodes, thus avoiding concentration polarization and response hysteresis caused by liquid absorption through pores, effectively improving the immediacy and accuracy of potential measurement. The electrodeless reaction structure avoids interference from the negative electrode hydrogen evolution side reaction on the potential signal, enhancing the reliability of SOC estimation. The diffusion control system constructed through the ion-conducting membrane makes the detection structure more stable and repeatable, suitable for continuous online SOC monitoring in large-scale flow battery systems. Its compact structure, convenient installation, and strong adaptability facilitate flexible integration into battery systems.

[0016] One feasible technical solution is that each bipolar plate 2 is provided with an inlet 22 and an outlet 21; like Figure 2 As shown in (a), the ion-conducting membrane 4 is configured as a flow channelless structure through the flow cavity formed between the support frame 3 and the bipolar plates 2 on both sides. The electrolyte diffuses freely in the flow cavity, which is simple in structure. However, when the thickness of the support frame 3 is relatively small and the space of the flow cavity is relatively small, it is not conducive to controlling the flow rate distribution and is prone to dead zones and concentration polarization.

[0017] like Figure 3 The image shows a cross-sectional view of the ion-conducting membrane 4 stacked with the bipolar plate 2 on one side via the support frame 3 when the flow cavity is configured as a channelless structure. Figure 3 Region A is the flow cavity. The size of this flow cavity is determined by the thickness of the support frame 3; A further technical solution involves an ion-conducting membrane forming a flow cavity between the support frame and the bipolar plates on both sides. A flow channel structure is provided on the bipolar plates 2 to accelerate the flow rate of the electrolyte, especially when the thickness of the support frame 3 is relatively small, thereby achieving uniform flow rate control. This embodiment adopts a bipolar plate flow channel structure design, which forms a fixed channel. Compared with the overall cavity, it can accelerate the flow rate of electrolyte in the battery and ensure the real-time state of charge of the electrolyte.

[0018] One specific implementation involves a flow channel structure on the bipolar plate 2, employing, as follows: Figure 2 The structure shown in (b) adopts a straight parallel flow channel structure, which consists of multiple parallel straight channels. Each straight channel has an inlet 22 and an outlet 21 at both ends. This achieves a multi-inlet and multi-outlet structure. It needs to be explained that, Figure 2 The circular holes in (a), (b), (c), (d), and (e) all represent through holes provided on bipolar plate 2, for example... Figure 2 (a) is provided with 8 liquid inlets 22 and 8 liquid outlets 21; A cross-sectional view of the ion-conducting membrane 4 stacked with the bipolar plate 2 on one side via the support frame 3 when a parallel flow channel structure is provided on the bipolar plate 2, as shown in the figure. Figure 4 As shown, in addition to flowing in the straight flow channel 23, the electrolyte can also flow laterally in the flow cavity A. The flow channel enables faster flow in the flow channel space, thereby improving the flow rate of the electrolyte. In this embodiment, the multiple direct current channels formed from the liquid inlet 22 to the liquid outlet 21 have low electrolyte flow resistance and uniform liquid distribution, making them suitable for low differential pressure systems; the manufacturing process is simple and maintenance is convenient. It is feasible to provide an inlet tank and an outlet tank on the battery end plate 1 for the structure of multiple inlets 22 and outlets 21. The inlet tank is opposite to and communicates with all the inlets 22, and the outlet tank is opposite to and communicates with all the outlets 21. In use, the inlet tank on the battery end plate 1 is used to connect the inlet conduit of the electrolyte to be tested. After the electrolyte to be tested is introduced into the inlet tank, it enters the flow cavity between the ion conduction membrane 4 and the bipolar plate 2 through each inlet 22. Another specific implementation method involves a flow channel structure on the bipolar plate 2, employing a method such as... Figure 2 The structure shown in (c) has a parallel flow channel structure with the flow channels arranged in parallel. The inlet and outlet channels are inter-inserted into each other, and the outlets are distributed vertically. When using, such as Figure 2In (c) the electrolyte enters from the inlet 22, flows through multiple inlets at the bottom, and quickly fills the positive and negative electrode support frames through multiple parallel main channels. The electrolyte then flows out from multiple outlets at the top through another main channel and out through outlet 21. The flow channel structure of this embodiment can improve the degree of fluid disturbance, improve the liquid exchange efficiency, and moderately reduce the boundary dead zone.

[0019] Another specific implementation method, such as Figure 2 As shown in (d), the flow channel structure on the bipolar plate 2 adopts a serpentine flow channel structure, and the flow channel is arranged in a continuous S-shaped serpentine pattern, forming a continuous channel from the liquid inlet 22 to the liquid outlet 21.

[0020] The flow channel structure of this embodiment allows for a long liquid flow path and a long fluid residence time, which is beneficial for uniform exchange and potential stability, but the pressure drop is relatively large.

[0021] Another specific implementation method, such as Figure 2 The structure shown in (e) is an interdigitated flow channel structure on the bipolar plate 2, which includes two sets of relatively parallel main flow channels. An inlet 22 is provided at the intersection of one of the interdigitated main flow channels, and an outlet 21 is provided at the intersection of the other comb-shaped main flow channel. When using, such as Figure 2 In section (e), the electrolyte enters through inlet 22, rapidly fills the positive and negative electrode support frames via the upper multi-channel flow, and then flows out through outlet 21 via the lower multi-channel flow. The electrolyte extends into the flow region from both inlet 22 and outlet 21, creating a complex path with multiple interconnected flow segments by adding transverse connecting channels. This design balances disturbance and flow rate control, improving fluid mixing and stability, and is suitable for high-precision measurements.

[0022] In some embodiments, the bipolar plate 2 is made of graphite.

[0023] In this embodiment, the bipolar plate 2 is made of graphite and combined with a detection structure that allows no current to pass through and no electrode reaction, so that it only serves as a potential acquisition terminal in the electrolyte without participating in any redox reactions. Graphite material has excellent conductivity and chemical stability, enabling it to maintain stable electrical performance for a long time in the electrolyte environment. It also has strong corrosion resistance, avoiding signal drift or detection errors caused by electrode material aging. The bipolar plate 2 acquires the open-circuit potential established by the diffusion of electrolyte across the ion-conducting membrane 4 through the voltage detection terminal, which is used to indirectly characterize the SOC state of the electrolyte.

[0024] This embodiment uses graphite as the bipolar plate material, which not only improves the overall conductivity of the device, but also significantly enhances its corrosion resistance in strongly acidic or strongly oxidizing electrolyte environments, ensuring the long-term stability and reliability of SOC detection. Graphite is moderately priced, has good processing performance, is suitable for large-scale preparation, and facilitates system integration and engineering applications.

[0025] In other implementation variations, the bipolar plate 2 can also be selected from other highly corrosion-resistant conductive materials, such as glassy carbon, titanium-based coating materials or carbon nanotube composite plates, as well as graphite plates and other metal current collector structures, such as graphite bipolar plate + copper current collector structure, to further optimize durability or conductivity. In some embodiments, the support frame 3 is a frame structure made of non-conductive material or a sealing gasket made of elastic material; The support frame 3 can also be an electrode frame. The electrode frame is a frame structure made of non-conductive material, which can be a frame structure made of rigid plastic or other non-conductive materials, used to limit the space of the electrolyte.

[0026] The support frame 3 can also be made of a sealing gasket or elastic material, which serves both as a seal and as a spatial boundary for the fluid channel.

[0027] Furthermore, the thickness of the electrode frame is 0.5 mm to 10 mm, and the thickness of the sealing gasket is 0.1 mm to 5 mm.

[0028] The detection device in this embodiment achieves accurate measurement of the state of charge (SOC) of the electrolyte under electrochemical static conditions by constructing an electrodeless reaction structure and combining it with a graphite bipolar plate with excellent conductivity and corrosion resistance. This device effectively avoids problems such as concentration polarization, response delay, and side reaction interference present in traditional carbon felt electrodes, significantly improving the stability and accuracy of the detection. Furthermore, its simple structure makes it easy to fabricate and integrate, making it suitable for online monitoring and intelligent management of flow battery systems, and it has promising engineering application prospects.

[0029] Example 2 Based on Embodiment 1, this embodiment provides a detection method for an electrolyte state of charge detection device for a fluid energy storage system as described in Embodiment 1, comprising the following steps: Step 1: Pass the positive electrolyte and negative electrolyte of the flow cell to be tested into the flow chambers on both sides of the ion conduction membrane 4, respectively. Step 2: Obtain the current temperature data; Step 3: Obtain the voltages collected by the voltage detection terminals on the two bipolar plates 2 according to the set sampling rate to obtain the open circuit voltage; Step 4: Calculate the SOC value of the electrolyte based on the current temperature data and open-circuit voltage; The formula for calculating the SOC value of the electrolyte is: ; Among them, E OCV For SOC battery testing, the open-circuit voltage is given by: R (ideal gas constant), T (absolute temperature), F (Faraday constant), and c(H). + p+ ) represents H in the positive electrode electrolyte + concentration.

[0030] This method is based on a stable open-circuit potential established under diffusion control, and achieves non-invasive SOC estimation by acquiring bipolar plate voltages. First, the positive and negative electrolytes of the flow battery under test are introduced into the flow chambers on both sides of the ion-conducting membrane in the detection device, ensuring the device is in an electrochemically static state. Then, the current ambient or electrolyte temperature is acquired using a temperature sensor, providing temperature correction parameters for SOC calculation. Next, the potential difference between the voltage detection terminals of the two graphite bipolar plates is acquired; this potential reflects the concentration ratio of ions after diffusion equilibrium on both sides of the membrane. Finally, the obtained open-circuit voltage and temperature data are substituted into a pre-calibrated potential-SOC function model to achieve quantitative calculation of the current electrolyte SOC.

[0031] This detection method has the advantages of no electrode reaction required, real-time sampling, and rapid response, which can significantly improve the accuracy and stability of SOC monitoring of flow battery systems. Combined with a temperature compensation mechanism, it enhances the algorithm's adaptability to environmental changes and effectively avoids the impact of potential drift on SOC judgment. The method has a clear structure, is simple to implement, and is easy to integrate into existing flow energy storage systems, making it suitable for large-scale deployment and long-term operation.

[0032] Example 3 Based on Example 2, this example provides an improved detection method. To improve the accuracy of SOC measurement, a reference electrolyte is used for measurement. This embodiment provides a detection method based on the electrolyte state-of-charge detection device for a fluid energy storage system described in Embodiment 1, comprising the following steps: Step 1: Pass the positive electrolyte of the flow cell to be tested and the reference electrolyte into the flow chambers on both sides of the ion conduction membrane 4 of the first detection device, respectively. Step 2: The negative electrolyte of the flow cell to be tested and the reference electrolyte are respectively introduced into the flow chambers on both sides of the ion conduction membrane 4 of the second detection device. The first and second detection devices are the electrolyte state-of-charge detection devices for a liquid flow energy storage system described in Example 1. Furthermore, in steps 1 and 2, the bipolar plate 2 for the reference electrolyte is set as an AgCl / Ag flat plate electrode; that is, the bipolar plate 2 on the side where the positive or negative electrolyte is set can be a graphite electrode, and the bipolar plate 2 on the side where the reference electrolyte is set is set as an AgCl / Ag flat plate electrode with the same size and shape as the graphite electrode.

[0033] In this embodiment, an AgCl / Ag electrode, a reference electrolyte, and an ion-conducting membrane are used to form a reference electrode. The Ag / AgCl electrode has a stable potential in the reference electrode electrolyte, which can more accurately test the absolute potential of the electrolyte. Step 3: Obtain the voltages collected by the voltage detection terminals on the two bipolar plates 2 of the first detection device according to the set sampling rate, and obtain the measured open-circuit voltage of the positive electrode electrolyte. ; Step 4: Obtain the voltages collected by the voltage detection terminals on the two bipolar plates 2 of the second detection device according to the set sampling rate, and obtain the measured open-circuit voltage of the negative electrode electrolyte. ; Step 5: Calculate the measured open-circuit voltage of the positive electrode electrolyte. Measurement of open-circuit voltage with negative electrode electrolyte The difference; Step 6: Calculate the SOC value of the electrolyte based on the obtained current temperature data and voltage difference; Furthermore, the reference electrolyte is a KCl electrolyte with a known concentration of 1M, 3M, or saturation, and during the measurement process, the reference electrolyte does not flow and is in direct contact with the AgCl / Ag electrode; The positive / negative electrolyte is separated from the reference electrolyte by an ion-conducting membrane 4; In step 6, the SOC value of the electrolyte is calculated using the following formula: ; In this embodiment, two sets of detection devices are used, and a reference electrode construction method is adopted to accurately test the absolute potential of the positive electrolyte / negative electrolyte, which can obtain a more accurate OCV and realize accurate SOC calculation.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0035] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An electrolyte state of charge detection device for a liquid flow energy storage system, characterized by, The application relates to a liquid flow battery, which comprises the following parts: a pair of battery end plates for providing mechanical compression and serving as a fixed housing structure; at least one pair of bipolar plates made of conductive material and arranged between the battery end plates; each bipolar plate is connected with a detection terminal for collecting an open circuit voltage signal established through electrolyte; an ion-conducting membrane is arranged between two bipolar plates, and a support frame with a set thickness is arranged between the ion-conducting membrane and the two bipolar plates respectively, so that the ion-conducting membrane and the two bipolar plates form flow-through cavities for containing electrolyte through the support frames; the flow-through cavities on the two sides of the ion-conducting membrane are respectively connected with positive electrolyte and negative electrolyte of a liquid flow battery to be detected, and a potential difference is formed on the two sides of the ion-conducting membrane.

2. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: An inlet and an outlet are arranged on each bipolar plate respectively.

3. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: A flow channel structure is arranged on the bipolar plate in the flow-through cavity formed between the ion-conducting membrane and the two bipolar plates through the support frames.

4. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 3, characterized by: The flow channel structure adopts a straight linear parallel flow channel structure, the flow channel is composed of a plurality of parallel linear channels, and an inlet and an outlet are arranged on two sections of each linear channel of the channel respectively.

5. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: The flow channel structure adopts a parallel flow channel structure, the flow channels are arranged in parallel, and the inlets and the outlets are arranged in an interpenetrating mode.

6. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: The flow channel structure adopts a serpentine flow channel structure, the flow channels are arranged in a continuous S-shaped serpentine mode, and a continuous channel is formed from the inlet to the outlet.

7. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: The flow channel structure arranged in the flow-through cavity adopts a cross comb structure, which comprises two groups of oppositely arranged comb main flow channels, an inlet is arranged at the intersection of one of the comb main flow channels, and an outlet is arranged at the intersection of the other comb main flow channel.

8. The electrolyte state of charge detection device for a liquid flow energy storage system according to claim 1, characterized by: The bipolar plate is made of graphite material; The support frame adopts a frame structure made of non-conductive material or a sealing gasket made of elastic material.

9. A method of detecting the state of charge of an electrolyte for a liquid flow energy storage system according to any one of claims 1 to 8, characterized in that The application further discloses a liquid flow battery detection method, which comprises the following steps: the flow-through cavities on the two sides of the ion-conducting membrane are respectively connected with positive electrolyte and negative electrolyte of a liquid flow battery to be detected; current temperature data are obtained; voltage collected by the voltage detection terminals on the two bipolar plates is obtained according to a set sampling rate, so that an open circuit voltage is obtained; the SOC value of the electrolyte is calculated according to the current temperature data and the open circuit voltage.

10. A method of detecting the state of charge of an electrolyte for a liquid flow energy storage system according to any one of claims 1 to 8, characterized in that The application further discloses a liquid flow battery detection method, which comprises the following steps: the flow-through cavities on the two sides of the ion-conducting membrane of the first detection device are respectively connected with positive electrolyte and reference electrolyte of a liquid flow battery to be detected; the flow-through cavities on the two sides of the ion-conducting membrane of the second detection device are respectively connected with negative electrolyte and reference electrolyte of a liquid flow battery to be detected; According to the set sampling rate, the voltage detected by the voltage detection terminals on the two bipolar plates of the first detection device is obtained, and the measured open circuit voltage of the positive electrolyte is obtained ; According to the set sampling rate, the voltage detected by the voltage detection terminals on the two bipolar plates of the second detection device is obtained, and the measured open circuit voltage of the negative electrolyte is obtained ; The measured open circuit voltage of the positive electrolyte is calculated as the difference between the measured open circuit voltage of the negative electrolyte and the measured open circuit voltage of the positive electrolyte ​ the SOC value of the electrolyte is calculated according to the obtained current temperature data and voltage difference.

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