Molten salt energy storage system based on electrochemical sensing technology

Abstract

The invention relates to the field of fused salt energy storage, and provides a fused salt energy storage system based on an electrochemical sensing technology, comprising: a fused salt energy storage module for storing and converting energy through a liquid-solid two-phase heat storage medium and a modular heat storage device; the electrochemical sensing module is used for collecting electrochemical parameters of the fused salt in real time through a dual-electrode system sensor; the data processing module is used for analyzing the corrosion product layer structure of the metal material in the molten salt based on the electrochemical impedance spectroscopy and calculating the ion diffusion rate, and calculating the corrosion rate in real time by combining the charge transfer resistance; and the intelligent control module is used for dynamically adjusting the rotating speed of the fused salt circulating pump and the steam heat exchange power according to the corrosion rate and triggering local isolation protection. Intelligent management of fused salt energy storage can be achieved, the efficiency and safety of fused salt energy storage are remarkably improved, remarkable advantages are shown in the aspects of improving energy efficiency, guaranteeing safe operation and reducing maintenance cost, and an efficient and stable solution is provided for the fields of new energy consumption, industrial waste heat utilization and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt energy storage, and particularly to a molten salt energy storage system based on electrochemical sensing technology. Background Art

[0002] As an efficient energy storage and conversion device, the molten salt energy storage system has broad application prospects in the fields of renewable energy consumption, industrial waste heat recovery, etc. The core of the molten salt energy storage system is to utilize the phase change characteristics of the liquid-solid two-phase heat storage medium to achieve efficient energy storage, and complete the heat transfer and conversion through the steam heat exchange pipeline and the molten salt circulation channel in the modular heat storage device. However, the molten salt will cause corrosion of metal materials in a high-temperature environment, which has always been a key factor restricting the long-term stable operation of the molten salt energy storage system. Traditional corrosion monitoring methods are difficult to obtain molten salt electrochemical parameters such as electrochemical impedance spectroscopy, corrosion potential, and charge transfer resistance in real time and accurately, which leads to the inability to deeply analyze the structure of the corrosion product layer and the ion diffusion rate, and thus affects the accurate evaluation of the corrosion rate. The introduction of electrochemical sensing technology provides a new path to solve this problem. By embedding sensors in the molten salt circulation channel and the steam heat exchange pipeline, key parameters can be collected in real time. However, how to combine the collected key parameters with the corrosion kinetics model to achieve dynamic analysis and intelligent control of the corrosion process still needs to be further optimized.

[0003] In the prior art, there are still deficiencies in the real-time monitoring and precise control of the molten salt corrosion process. On the one hand, the analysis of the corrosion product layer structure relies on single parameters or simplified models, and fails to fully integrate the full-frequency band information of the electrochemical impedance spectroscopy, resulting in limited calculation accuracy of porosity, stratification thickness, and ion diffusion rate. On the other hand, the linkage between the real-time calculation of the corrosion rate and the system control strategy is weak, making it difficult to dynamically adjust key parameters such as the rotation speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion state, and it is also impossible to achieve adaptive control of the corrosion inhibitor addition amount and intelligent triggering of the molten salt replacement program. In addition, the long-term stability and data reliability of the sensor in the high-temperature molten salt environment also affect the overall performance of the molten salt energy storage system. Summary of the Invention

[0004] The present invention aims to solve at least one of the problems existing in the prior art, and provides a molten salt energy storage system based on electrochemical sensing technology.

[0005] In one aspect of the present invention, there is provided a molten salt energy storage system based on electrochemical sensing technology, and the molten salt energy storage system based on electrochemical sensing technology includes a molten salt energy storage module, an electrochemical sensing module, a data processing module, and an intelligent control module; The molten salt energy storage module is used to store and convert energy through a liquid-solid two-phase heat storage medium and a modular heat storage device; The electrochemistry sensing module is electrically connected to the molten salt energy storage module. The electrochemistry sensing module is used to collect the electrochemistry parameters of the molten salt in real time through a two-electrode system sensor. The electrochemistry parameters include: electrochemical impedance spectroscopy, corrosion potential, and charge transfer resistance; The data processing module is electrically connected to the electrochemistry sensing module. The data processing module has a built-in corrosion kinetics model, which is used to analyze the corrosion product layer structure of the metal material in the molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, and calculate the corrosion rate in real time in combination with the charge transfer resistance; The intelligent control module is electrically connected to the data processing module. The intelligent control module is used to dynamically adjust the rotation speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger local isolation protection for the molten salt circulation channel.

[0006] Preferably, the liquid-solid two-phase heat storage medium includes a high-temperature resistant metal oxide solid skeleton and a molten salt liquid; a steam heat exchange pipeline and a molten salt circulation channel are arranged inside the modular heat storage device.

[0007] Preferably, the two-electrode system sensor collects the electrochemistry parameters by being embedded in the steam heat exchange pipeline and the molten salt circulation channel. The working electrode and the counter electrode surfaces of the two-electrode system sensor are polished with 1200-mesh sandpaper and coated with a nanoscale protective layer. The signal acquisition frequency range of the two-electrode system sensor is 0.01 mHz to 100 kHz.

[0008] Preferably, the data processing module is used to analyze the corrosion product layer structure of the metal material in the molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, including: The data processing module is used to: preprocess the electrochemical impedance spectroscopy, use the Kramers-Kronig transformation to verify the data causality and linear conditions, and when the deviation between the calculated imaginary part value and the measured value is less than a preset threshold, determine that the data is valid; construct an equivalent circuit model including the molten salt bulk resistance, the capacitance and resistance of the corrosion product layer, the double-layer capacitance, the charge transfer resistance, and the Warburg diffusion impedance; calculate the porosity and stratification thickness of the corrosion product layer based on the constant phase angle element, and calculate the ion diffusion rate through the Warburg impedance characteristics.

[0009] Preferably, the calculation of the porosity and stratification thickness of the corrosion product layer based on the constant phase angle element includes: Calculating the porosity according to the admittance constant and capacitance index value of the constant phase angle element; Calculating the stratification thickness according to the effective diffusion coefficient, reaction rate constant, the porosity, and the ionic conductivity.

[0010] Preferably, calculating the ion diffusion rate through the Warburg impedance characteristic includes: Extracting the Warburg coefficient based on the linear relationship between the real part of the impedance in the low-frequency region and the reciprocal of the square root of the frequency, and deriving the effective diffusion coefficient by combining the gas constant, temperature, ion charge number, Faraday constant, electrode area, and the concentration of the molten salt bulk.

[0011] Preferably, combining the charge transfer resistance to calculate the corrosion rate in real time includes: Separating the charge transfer resistance through equivalent circuit fitting; Based on the Stern-Geary equation, converting the charge transfer resistance into the corrosion current density; Based on the metal molar mass, number of electrons, Faraday constant, and metal density, converting the corrosion current density into the thickness loss rate as the corrosion rate.

[0012] Preferably, the intelligent control module is used to dynamically adjust the rotation speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger local isolation protection for the molten salt circulation channel, including: Adopting a proportional-integral-derivative algorithm to establish a rotation speed adjustment model for the molten salt circulation pump, and dynamically adjusting the rotation speed of the molten salt circulation pump by using the rotation speed adjustment amount of the molten salt circulation pump output based on the corrosion rate calculated in real time and the safe corrosion rate threshold; Based on the non-linear relationship between the corrosion rate and the material characteristic coefficient, establishing a steam heat exchange power adjustment model, and dynamically adjusting the steam heat exchange power to the adjusted steam heat exchange power output by the steam heat exchange power adjustment model based on the coupling relationship between the corrosion rate and the heat capacity of the molten salt; When the corrosion rate exceeds the maximum allowable value, trigger local isolation protection for the molten salt circulation channel and activate the standby circulation channel, ensuring that the switching time of the standby circulation channel is less than or equal to the ratio of the critical thickness of the corrosion product layer to the corrosion rate.

[0013] Preferably, the intelligent control module is further used for: Based on the porosity and effective diffusion coefficient of the corrosion product layer, calculating the addition amount of the corrosion inhibitor in real time, and adjusting the molten salt composition according to the addition amount of the corrosion inhibitor; wherein, the addition amount of the corrosion inhibitor is linearly and positively correlated with the porosity, and the addition amount of the corrosion inhibitor is non-linearly and positively correlated with the effective diffusion coefficient; Monitoring the adsorption efficiency of the corrosion inhibitor through the change rate of the charge transfer resistance, and triggering the molten salt replacement program to perform molten salt replacement when the adsorption efficiency is lower than the preset adsorption threshold, wherein the molten salt replacement amount is related to the exponential decay function of the molten salt deterioration time.

[0014] Preferably, the molten salt energy storage system based on the electrochemical sensing technology further includes a multi-sensor redundancy verification module; the multi-sensor redundancy verification module includes at least two groups of sensors symmetrically arranged in the molten salt circulation channel and the steam heat exchange pipeline in the modular heat storage device; The multi-sensor redundancy verification module is used for: dynamically adjusting the weighted fusion coefficient of the double-electrode system sensor through the historical error of the double-electrode system sensor; when the error of a certain group of the double-electrode system sensors exceeds the tolerance, switching to the standby sensor group, and calibrating the output value of the double-electrode system sensor with an error exceeding the tolerance by using temperature drift compensation and baseline offset.

[0015] The molten salt energy storage system based on the electrochemical sensing technology provided by the present invention significantly improves the efficiency and safety of molten salt energy storage by integrating an electrochemical sensing module, an intelligent control module, and a molten salt energy storage module. Among them, the electrochemical sensing module can collect the electrochemical parameters of molten salt in real time. On this basis, a data processing module with a corrosion kinetics model can accurately analyze the structure of the corrosion product layer and the ion diffusion rate, providing a scientific basis for corrosion state assessment. The intelligent control module can dynamically adjust the rotation speed of the molten salt circulation pump and the steam heat exchange power, effectively delaying the corrosion process and extending the service life of the equipment. At the same time, the modular heat storage device in the molten salt energy storage module uses a liquid-solid two-phase medium, which can enhance the thermal stability and improve the energy storage performance. Its flexible and scalable design is convenient for system optimization and maintenance. The molten salt energy storage system based on the electrochemical sensing technology provided by the present invention realizes the intelligent management of molten salt energy storage, showing significant advantages in improving energy efficiency, ensuring safe operation, and reducing maintenance costs, and providing an efficient and stable solution for fields such as new energy consumption and industrial waste heat utilization. Description of the Drawings

[0016] Figure 1 is a module framework diagram of a molten salt energy storage system based on the electrochemical sensing technology provided by the present invention; Figure 2 is a working flow chart of a molten salt energy storage system based on the electrochemical sensing technology provided by the present invention. Detailed Embodiments

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.

[0018] As Figure 1 shown, a molten salt energy storage system based on the electrochemical sensing technology includes a molten salt energy storage module, an electrochemical sensing module, a data processing module, and an intelligent control module. The following will describe each module in detail in combination with Figure 1 this.

[0019] The molten salt energy storage module is used to store and convert energy through a liquid-solid two-phase heat storage medium and a modular heat storage device.

[0020] The electrochemical sensing module is electrically connected to the molten salt energy storage module. The electrochemical sensing module is used to collect the electrochemical parameters of the molten salt in real time through a double-electrode system sensor. The electrochemical parameters include: electrochemical impedance spectroscopy, corrosion potential, and charge transfer resistance.

[0021] The data processing module is electrically connected to the electrochemical sensing module. The data processing module has a built-in corrosion kinetics model, which is used to analyze the corrosion product layer structure of the metal material in the molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, and calculate the corrosion rate in real time in combination with the charge transfer resistance.

[0022] The intelligent control module is electrically connected to the data processing module. The intelligent control module is used to dynamically adjust the rotation speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger the local isolation protection of the molten salt circulation channel.

[0023] Exemplarily, the liquid-solid two-phase heat storage medium includes a high-temperature resistant metal oxide solid skeleton and a molten salt liquid. Combine together Figure 1 and the modular heat storage device is internally provided with a steam heat exchange pipeline and a molten salt circulation channel.

[0024] Exemplarily, combine together Figure 1 and the double-electrode system sensor collects the electrochemical parameters of the molten salt by being embedded in the steam heat exchange pipeline and the molten salt circulation channel. The working electrode and the counter electrode surface of the double-electrode system sensor are polished with 1200-mesh sandpaper and coated with a nanoscale protective layer. The signal acquisition frequency range of the double-electrode system sensor is 0.01 mHz~100 kHz, and this acquisition frequency range can cover the full-frequency monitoring of the high-frequency capacitive reactance arc and the low-frequency diffusion resistance during the molten salt corrosion process. Among them, "mHz" represents "millihertz" in the frequency unit, and 1 millihertz is equal to 0.001 hertz (Hz).

[0025] Exemplarily, the data processing module is used to analyze the corrosion product layer structure of the metal material in the molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, including: the data processing module is used to: preprocess the electrochemical impedance spectroscopy, use the Kramers-Kronig transformation to verify the causality and linear conditions of the data, and when the deviation between the calculated value and the measured value of the imaginary part is less than the preset threshold, determine that the data is valid; construct an equivalent circuit model including the resistance of the molten salt body, the capacitance and resistance of the corrosion product layer, the double-layer capacitance, the charge transfer resistance, and the Warburg diffusion impedance; calculate the porosity and stratification thickness of the corrosion product layer based on the constant phase angle element, and calculate the ion diffusion rate through the Warburg impedance characteristics.

[0026] Among them, preprocessing the electrochemical impedance spectrum specifically includes: performing mathematical transformation on the electrochemical impedance spectrum data in the electrochemical parameters collected by the electrochemical sensing module, verifying the causality and linear conditions of the data, and determining that the data is valid when the deviation between the calculated imaginary part value and the measured value is less than the preset threshold; constructing an equivalent circuit model, which includes the bulk resistance of the molten salt, the capacitance and resistance of the corrosion product layer, the double-layer capacitance, the charge transfer resistance, and the Warburg diffusion impedance.

[0027] During the preprocessing of the electrochemical impedance spectrum, when verifying the causality and linear conditions of the data, the Kramers-Kronig transformation is used to verify the data validity, and its calculation formula is:

[0028] Among them, is the calculated value of the impedance. is the angular frequency of the current analysis. is the auxiliary variable in the integral, representing the angular frequency traversed during the integral process. is the real part of the impedance at the frequency at the experimental measurement value. is the limit value of the real part of the impedance when the frequency is infinite.

[0029] After preprocessing the electrochemical impedance spectrum, analyze the structure of the corrosion product layer and calculate the ion diffusion rate. Among them, analyzing the structure of the corrosion product layer includes: calculating the porosity and delamination thickness of the corrosion product layer based on the constant phase element. Calculating the ion diffusion rate includes: extracting the Warburg coefficient through the Warburg impedance characteristics and calculating the effective diffusion coefficient accordingly.

[0030] Exemplarily, calculating the porosity of the corrosion product layer based on the constant phase element includes: characterizing the capacitance characteristics of the corrosion product layer through the constant phase element, calculating the porosity distribution of the layered structure of the corrosion product layer in combination with the resistance value, and judging the compactness of the corrosion product layer according to the capacitance index value. Among them, the compactness of the corrosion product layer includes a dense protective layer and a porous structure.

[0031] In other words, calculating the porosity of the corrosion product layer based on the constant phase element includes: calculating the porosity according to the admittance constant and capacitance index value of the constant phase element, and the corresponding calculation formula is:

[0032] Among them, is the porosity of the corrosion product layer, is the admittance constant of the constant phase element, is the imaginary unit, is the capacitance index value of the constant phase element.

[0033] Calculating the stratified thickness of the corrosion product layer based on a constant phase angle element includes: calculating the actual stratified thickness of the corrosion product layer according to the effective diffusion coefficient, reaction rate constant, ionic conductivity, and porosity, and its calculation formula is:

[0034] Wherein, is the actual stratified thickness of the corrosion product layer, is the effective diffusion coefficient, is the reaction rate constant, is the porosity, is the ionic conductivity.

[0035] Exemplarily, calculating the ion diffusion rate through Warburg impedance characteristics includes: extracting the Warburg coefficient based on the linear relationship between the real part of the impedance in the low-frequency region and the reciprocal of the square root of the frequency through Warburg impedance characteristics, and further deriving the effective diffusion coefficient in combination with the gas constant, temperature, ion charge number, Faraday constant, electrode area, and bulk concentration of the molten salt.

[0036] Wherein, the calculation formula of Warburg impedance characteristics is:

[0037] Wherein, is the Warburg impedance, which is an impedance component caused by the diffusion process. is the Warburg coefficient, which is related to the diffusion rate and concentration gradient and is obtained through the slope in the low-frequency region. is the angular frequency. is the imaginary unit, representing the imaginary part phase of the impedance.

[0038] The calculation formula of the effective diffusion coefficient is:

[0039] Wherein, is the effective diffusion coefficient, is the gas constant, is the absolute temperature, is the charge number of ion transfer, is the Faraday constant, is the electrode area, is the bulk concentration of the molten salt.

[0040] Exemplarily, calculating the corrosion rate in real time in combination with the charge transfer resistance includes: separating the charge transfer resistance through equivalent circuit fitting; converting the charge transfer resistance into the corrosion current density based on the Stern-Geary equation; and converting the corrosion current density into the thickness loss rate as the corrosion rate based on the metal molar mass, number of electrons, Faraday constant, and density parameter.

[0041] Specifically, when separating the charge transfer resistance through equivalent circuit fitting, first, separate the impedance component corresponding to the charge transfer process from the electrochemical impedance spectrum, obtain the charge transfer resistance value through equivalent circuit fitting, and then solve and calculate by fitting the impedance data using the least squares method. The calculation formula is:

[0042] where is to find the minimum value of the subsequent expression, is the total number of experimentally measured frequency points, is the impedance value at the i-th frequency point measured experimentally, is the impedance value of the equivalent circuit model, is the frequency at the i-th frequency point, is the charge transfer resistance, is the constant phase element parameter, is the Warburg impedance parameter.

[0043] When converting the charge transfer resistance into the corrosion current density based on the Stern-Geary equation, the formula is:

[0044] where is the corrosion current density. is the Stern-Geary constant, and its calculation formula is:

[0045] where is the anodic slope, , is the cathodic slope, , E represents the electrode potential, represents the logarithm of the cathodic current density corresponding to the i-th frequency point, represents the anode, represents the cathode.

[0046] When converting the corrosion current density into the thickness loss rate as the corrosion rate based on the metal molar mass, number of electrons, Faraday constant, and metal density, the corresponding calculation formula is:

[0047] Among them, is the thickness loss rate, i.e., the corrosion rate, is the molar mass of the metal, is the number of electrons in the oxidation reaction, is the Faraday constant, is the metal density.

[0048] Exemplarily, the intelligent control module is used to dynamically adjust the rotational speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger local isolation protection for the molten salt circulation channel, including: Establish a rotational speed adjustment model for the molten salt circulation pump using the proportional-integral-derivative algorithm, and dynamically adjust the rotational speed of the molten salt circulation pump by using the rotational speed adjustment amount of the molten salt circulation pump output based on the corrosion rate calculated in real time and the safety threshold; among them, the input parameters of the rotational speed adjustment model of the molten salt circulation pump are the corrosion rate calculated in real time and the molten salt temperature, and the output parameter is the rotational speed adjustment amount, and its calculation formula is:

[0049] Among them, is the rotational speed adjustment amount, , , are the proportional coefficient, integral coefficient, and differential coefficient respectively, is the corrosion rate, is the molten salt temperature, is the safety corrosion rate threshold; Based on the non-linear relationship between the corrosion rate and the material characteristic coefficient, establish a steam heat exchange power adjustment model, and dynamically adjust the steam heat exchange power to the adjusted steam heat exchange power output by the steam heat exchange power adjustment model based on the coupling relationship between the corrosion rate and the molten salt heat capacity. Among them, the calculation formula for the adjusted steam heat exchange power output by the steam heat exchange power adjustment model based on the coupling relationship between the corrosion rate and the molten salt heat capacity is:

[0050] Among them, is the adjusted steam heat exchange power, is the reference heat exchange power, and are both material characteristic coefficients, is the maximum allowable corrosion rate; among them, is the linear influence coefficient, which is used to quantify the linear adjustment amplitude of the corrosion rate on the steam heat exchange power and reflect the sensitivity of the material's heat conduction characteristics in the corrosion environment; is the non-linear correction exponent, which characterizes the strength of the non-linear relationship between the corrosion rate and the heat exchange power and is used to describe the non-linear influence of the structure of the material corrosion product layer on the thermal resistance. Among them and The coefficient determination method for is as follows: Place the target metal material (such as 316L stainless steel, Inconel 625, etc.) in a high-temperature molten salt (such as a potassium nitrate-sodium nitrate mixture) for a material corrosion experiment. Use an electrochemical workstation to collect parameters such as impedance spectra and corrosion potential during the corrosion process in real time, synchronously monitor the coupling relationship between steam heat transfer power and corrosion rate, and use the non-linear least squares method to substitute the "corrosion rate - heat transfer power" data measured in the experiment into the steam heat transfer power calculation formula for optimization and solution and to minimize the mean square error between the model prediction value and the measured value. Verify the universality of the coefficient through multiple groups of working condition experiments with different temperatures and molten salt components

[0051] For 316L stainless steel, a typical value range is that its linear influence coefficient is 0.1 - 0.5, and the non-linear correction exponent is 1.2 - 2.0. For Inconel 625 nickel-based alloy, its linear influence coefficient is 0.05 - 0.3, and the non-linear correction exponent is 0.8 - 1.5

[0052] When the corrosion rate exceeds the maximum allowable value , trigger local isolation protection for the molten salt circulation channel, close the faulty area through a solenoid valve, and activate the standby circulation channel to ensure that the switching time of the standby circulation channel satisfies:

[0053] wherein, is the critical thickness of the corrosion product layer

[0054] Exemplarily, the intelligent control module is further configured to: Based on the porosity and the effective diffusion coefficient of the corrosion product layer, calculate the addition amount of the corrosion inhibitor in real time, and adjust the molten salt composition according to the addition amount of the corrosion inhibitor wherein, the calculation formula for the addition amount of the corrosion inhibitor is:

[0055] wherein, is the addition amount of the corrosion inhibitor, , are both weight coefficients, and are the reference porosity and the reference diffusion coefficient respectively, is a non-linear correction exponent; it can be seen from the calculation formula of the inhibitor addition amount that the inhibitor addition amount is linearly positively correlated with the porosity, and the inhibitor addition amount is non-linearly positively correlated with the effective diffusion coefficient; The adsorption efficiency of the inhibitor is monitored by the change rate of the charge transfer resistance. The calculation formula of the adsorption efficiency of the inhibitor is:

[0056] where, is the adsorption efficiency of the inhibitor, is the charge transfer resistance without adding the inhibitor, is the current charge transfer resistance after adding the inhibitor; When the adsorption efficiency of the inhibitor is lower than the preset adsorption threshold i.e., a molten salt replacement program is triggered to perform molten salt replacement. Among them, the molten salt replacement amount satisfies:

[0057] where, is the molten salt replacement amount, is the total molten salt capacity, is the attenuation coefficient, is the molten salt deterioration time. Obviously, the molten salt replacement amount is related to the exponential decay function of the molten salt deterioration time.

[0058] Exemplarily, the molten salt energy storage system based on the electrochemical sensing technology further includes a multi-sensor redundancy verification module. The multi-sensor redundancy verification module includes at least two groups of double-electrode system sensors symmetrically arranged in the molten salt circulation channel and the steam heat exchange pipeline in the modular heat storage device.

[0059] In the multi-sensor redundancy verification module, the measurement data of each group of double-electrode system sensors is processed by a weighted fusion algorithm. The fused electrochemical impedance spectrum is expressed as:

[0060] where, is the fused electrochemical impedance spectrum, is the weight coefficient of the th group of double-electrode system sensors, and satisfies , is the impedance data of the th group of double-electrode system sensors, represents the number of groups of double-electrode system sensors.

[0061] The multi-sensor redundancy verification module is used to: dynamically adjust the weighted fusion coefficient of the double-electrode system sensors, that is, the weight coefficient, through the historical error of the double-electrode system sensors. Among them, the Weight coefficient of the sensor of the double - electrode system group The calculation formula is as follows:

[0062] Wherein, is the historical error of the -th group of sensors of the double - electrode system, is the cumulative value of the historical errors of the -th group of sensors of the double - electrode system within a period of time, , is the observation value of the -th group of sensors of the double - electrode system at the -th frequency point, is the average value of the observation values of the multi - sensors at the -th frequency point.

[0063] The multi - sensor redundancy check module is also used for: when the error of a certain group of sensors of the double - electrode system exceeds the tolerance , switch to the backup sensor group, trigger the calibration program, and calibrate the output value of the sensors of the double - electrode system with an error exceeding the tolerance by using temperature drift compensation and baseline offset. The calculation formula for the output value of the calibrated sensors of the double - electrode system is:

[0064] Wherein, is the output value of the calibrated sensors of the double - electrode system, is the original output value of the sensors of the double - electrode system, is the temperature drift coefficient, is the temperature difference, is the baseline offset compensation amount.

[0065] Combined with Figure 2, the working process of the molten salt energy storage system based on electrochemical sensing technology provided by the present invention is as follows: during system operation, the molten salt energy storage module efficiently stores and converts energy in the modular device through the liquid-solid two-phase heat storage medium. The electrochemical sensing module uses a double-electrode system sensor to continuously collect the electrochemical parameters of the molten salt, including electrochemical impedance spectroscopy, corrosion potential, and charge transfer resistance. The data processing module judges the data validity of the electrochemical impedance spectroscopy through data analysis. When the data is invalid, it can issue a data anomaly prompt. When the data is valid, it constructs an equivalent circuit model through data analysis to analyze the structure of the corrosion product layer and calculates the corrosion rate in real time in combination with the charge transfer resistance. When the corrosion rate is less than or equal to the safety threshold, the intelligent control module keeps the molten salt energy storage system in a normal operation state. When the corrosion rate is greater than the safety threshold, it dynamically adjusts the rotation speed of the circulation pump and the steam heat exchange power. When the corrosion rate does not exceed the maximum allowable value, it continues to monitor. When the corrosion rate exceeds the maximum allowable value, it triggers the local isolation of the molten salt circulation channel and switches to the standby circulation channel, automatically calculates the dosage of the corrosion inhibitor and monitors its adsorption efficiency, and starts the molten salt replacement program when necessary. The molten salt energy storage system also verifies the output data of the double-electrode system sensor through the sensor redundancy verification module to ensure reliable data, and automatically compensates and calibrates when the data is abnormal, realizing the cyclic monitoring and closed-loop management of efficiency optimization and corrosion control.

[0066] The molten salt energy storage system based on electrochemical sensing technology provided by the above embodiment of the present invention can realize the real-time and accurate monitoring of the molten salt corrosion state through electrochemical sensing technology. By combining the equivalent circuit model and the corrosion kinetics model to analyze the structure of the corrosion product layer of the metal material in the molten salt and calculate the ion diffusion rate, it can significantly improve the calculation accuracy of the porosity, stratification thickness, and ion diffusion rate of the corrosion product layer, providing a reliable basis for corrosion rate evaluation; the intelligent control module dynamically adjusts the rotation speed of the molten salt circulation pump and the steam heat exchange power based on the corrosion rate calculated in real time, which can effectively delay the loss of metal materials, extend the service life of the equipment, and can also quickly trigger the local isolation protection of the molten salt circulation pipeline when the corrosion rate exceeds the maximum allowable value, isolate the faulty area, and ensure the continuous operation of the system; the modular heat storage device uses the liquid-solid two-phase heat storage medium to enhance the thermal stability, combined with the self-adaptive calculation of the corrosion inhibitor dosage and the intelligent trigger mechanism of molten salt replacement, reducing the maintenance cost; the multi-sensor redundancy verification module ensures the long-term stability of data acquisition in high-temperature environments through dynamic weighted fusion and temperature drift compensation, forming a full closed-loop management of "monitoring - analysis - regulation - maintenance", and finally realizing the multi-dimensional optimization of molten salt energy storage efficiency improvement, corrosion risk precise control, and system safety, providing efficient and reliable technical support for the new energy and industrial waste heat fields.

[0067] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements will occur to the present invention, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A molten salt energy storage system based on electrochemical sensing technology, characterized in that, The molten salt energy storage system based on electrochemical sensing technology includes a molten salt energy storage module, an electrochemical sensing module, a data processing module, and an intelligent control module; The molten salt energy storage module is used to store and convert energy through a liquid-solid two-phase heat storage medium and a modular heat storage device; The electrochemical sensing module is electrically connected to the molten salt energy storage module. The electrochemical sensing module is used to collect the electrochemical parameters of molten salt in real time through a two-electrode system sensor. The electrochemical parameters include electrochemical impedance spectroscopy, corrosion potential, and charge transfer resistance; The data processing module is electrically connected to the electrochemical sensing module. The data processing module has a built-in corrosion kinetics model, which is used to analyze the corrosion product layer structure of the metal material in molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, and calculate the corrosion rate in real time in combination with the charge transfer resistance; The intelligent control module is electrically connected to the data processing module. The intelligent control module is used to dynamically adjust the rotation speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger local isolation protection for the molten salt circulation channel.

2. The molten salt energy storage system based on the electrochemical sensing technology according to claim 1, characterized in that The liquid-solid two-phase heat storage medium includes a high-temperature resistant metal oxide solid skeleton and a molten salt liquid; the modular heat storage device is internally provided with a steam heat exchange pipeline and a molten salt circulation channel.

3. The molten salt energy storage system based on the electrochemical sensing technology according to claim 2, characterized in that, The dual - electrode system sensor collects the electrochemical parameters by being embedded in the steam heat - exchange pipeline and the molten salt circulation channel. The working electrode and the counter electrode surfaces of the dual - electrode system sensor are polished with 1200 - mesh sandpaper and coated with a nano - level protective layer. The signal acquisition frequency range of the dual - electrode system sensor is 0.01 mHz to 100 kHz.

4. The molten salt energy storage system based on the electrochemical sensing technology according to claim 1, wherein The data processing module is used to analyze the corrosion product layer structure of the metal material in molten salt based on the electrochemical impedance spectroscopy and calculate the ion diffusion rate, including: The data processing module is used to: preprocess the electrochemical impedance spectroscopy, verify the data causality and linear conditions by using the Kramers-Kronig transform, and determine that the data is valid when the deviation between the calculated value and the measured value of the imaginary part is less than a preset threshold; construct an equivalent circuit model including the resistance of the molten salt body, the capacitance and resistance of the corrosion product layer, the double-layer capacitance, the charge transfer resistance, and the Warburg diffusion impedance; calculate the porosity and stratification thickness of the corrosion product layer based on the constant phase angle element, and calculate the ion diffusion rate through the Warburg impedance characteristics.

5. The molten salt energy storage system based on the electrochemical sensing technology according to claim 4, characterized in that, The calculation of the porosity and stratification thickness of the corrosion product layer based on the constant phase angle element includes: Calculate the porosity according to the admittance constant and capacitance index value of the constant phase angle element; Calculate the stratification thickness according to the effective diffusion coefficient, reaction rate constant, porosity, and ionic conductivity.

6. The molten salt energy storage system based on the electrochemical sensing technology according to claim 4, wherein The calculation of the ion diffusion rate through the Warburg impedance characteristics includes: Extract the Warburg coefficient based on the linear relationship between the real part of the impedance in the low-frequency region and the reciprocal of the square root of the frequency, and deduce the effective diffusion coefficient in combination with the gas constant, temperature, ionic charge number, Faraday constant, electrode area, and molten salt body concentration.

7. The molten salt energy storage system based on the electrochemical sensing technology according to claim 1, characterized in that, The real-time calculation of the corrosion rate in combination with the charge transfer resistance includes: Separate the charge transfer resistance by equivalent circuit fitting; Based on the Stern-Geary equation, convert the charge transfer resistance into a corrosion current density; Based on the metal molar mass, number of electrons, Faraday constant, and metal density, convert the corrosion current density into a thickness loss rate as the corrosion rate.

8. The molten salt energy storage system based on the electrochemical sensing technology according to claim 1, characterized in that, The intelligent control module is used to dynamically adjust the rotational speed of the molten salt circulation pump and the steam heat exchange power according to the corrosion rate, and trigger local isolation protection for the molten salt circulation channel, including: Establish a rotational speed adjustment model of the molten salt circulation pump using the proportional-integral-derivative algorithm, and dynamically adjust the rotational speed of the molten salt circulation pump by using the rotational speed adjustment amount of the molten salt circulation pump output based on the corrosion rate calculated in real time and the safe corrosion rate threshold by the rotational speed adjustment model of the molten salt circulation pump; Based on the non-linear relationship between the corrosion rate and the material characteristic coefficient, establish a steam heat exchange power adjustment model, and dynamically adjust the steam heat exchange power to the adjusted steam heat exchange power output by the steam heat exchange power adjustment model based on the coupling relationship between the corrosion rate and the heat capacity of the molten salt; When the corrosion rate exceeds the maximum allowable value, trigger local isolation protection for the molten salt circulation channel and activate the standby circulation channel, ensuring that the switching time of the standby circulation channel is less than or equal to the ratio of the critical thickness of the corrosion product layer to the corrosion rate.

9. The molten salt energy storage system based on the electrochemical sensing technology according to claim 8, wherein The intelligent control module is also used for: Based on the porosity and effective diffusion coefficient of the corrosion product layer, calculate the addition amount of the corrosion inhibitor in real time, and adjust the molten salt composition according to the addition amount of the corrosion inhibitor; wherein, the addition amount of the corrosion inhibitor is linearly and positively correlated with the porosity, and the addition amount of the corrosion inhibitor is non-linearly and positively correlated with the effective diffusion coefficient; Monitor the adsorption efficiency of the corrosion inhibitor through the change rate of the charge transfer resistance, and when the adsorption efficiency is lower than the preset adsorption threshold, trigger the molten salt replacement procedure to perform molten salt replacement, wherein the molten salt replacement amount is related to the exponential decay function of the molten salt deterioration time.

10. The molten salt energy storage system based on the electrochemical sensing technology according to claim 2, characterized in that, The molten salt energy storage system based on the electrochemical sensing technology further includes a multi-sensor redundancy verification module; the multi-sensor redundancy verification module includes at least two groups of the double-electrode system sensors symmetrically arranged in the molten salt circulation channel and the steam heat exchange pipeline in the modular heat storage device; The multi-sensor redundancy verification module is used for: dynamically adjusting the weighted fusion coefficient of the double-electrode system sensors through the historical errors of the double-electrode system sensors; when the error of a certain group of the double-electrode system sensors exceeds the tolerance, switch to the standby sensor group, and calibrate the output value of the double-electrode system sensor with an error exceeding the tolerance by using temperature drift compensation and baseline shift.

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