11 results about "Ac impedance spectra" patented technology

The invention belongs to the technical field of energy storage batteries, and discloses an energy storage battery state evaluation method based on a generated impedance spectrum and a related device. The method comprises the following steps: acquiring impedance data of a to-be-evaluated energy storage battery; equivalent circuit fitting is carried out based on the impedance data of the energy storage battery to be evaluated, and equivalent element parameters are obtained; the correlation degree between the equivalent element parameters and the battery health state is calculated, and parameters with the correlation degree larger than a threshold value are selected as characteristic parameters; and inputting the characteristic parameters into a pre-established energy storage battery SOH evaluation model based on the generative impedance spectroscopy to obtain the health state of the energy storage battery to be evaluated. According to the invention, the test speed of the AC impedance spectroscopy and the interpretability of the evaluation model are considered; a full-spectrum alternating-current impedance spectrum is generated by using an adversarial neural network through a few points in different frequency ranges, so that the problems that full-spectrum testing time is long and engineering application is not facilitated are solved; and performing equivalent circuit analysis by using the generated full spectrum, and performing health state evaluation of the energy storage battery.

The invention relates to the technical field of fuel cell state evaluation, in particular to a fuel cell health state estimation method and system, and the method comprises the steps: continuously collecting the monomer polarization curve, pile AC impedance spectrum and gas flow channel pressure pulsation time sequence data of a target fuel cell in multiple operation cycles; ohm, activation and concentration polarization component decomposition are carried out on the polarization curve, a corresponding voltage loss component is extracted, correlation matching calculation is carried out on the corresponding voltage loss component and an impedance spectrum, and a polarization loss-impedance characteristic mapping relation is constructed. And extracting a pressure fluctuation mode synchronous with the polarization curve time sequence, and identifying an extra concentration difference loss component caused by the gas diffusion barrier by correlating the concentration difference polarization loss voltage. And integrating the component, the mapping relation and a reference aging model to calculate a comprehensive health state index. The multi-aging superposition state of the membrane electrode, the proton exchange membrane and the gas diffusion layer can be accurately reflected, aging inducement distinguishing is refined, and the accuracy of health state characterization is improved.

The invention provides a decommissioned battery detection method and device, a battery management system and a storage medium, and the method comprises the steps: obtaining multi-source internal characteristic data of a to-be-detected decommissioned battery, the internal characteristic data comprising at least one of an AC impedance spectrum, pulse characteristic data and a constant-current discharge curve; inputting the multi-source internal characteristic data into a battery health state evaluation model, and obtaining a health state evaluation result of the retired battery output by the battery health state evaluation model; wherein the battery health state evaluation model is a model formed by fusing a physical model based on an electrochemical mechanism and a machine learning model. According to the invention, through fusion of an electrochemical mechanism and machine learning, the detection accuracy of the health state of the retired battery is improved.

The invention discloses a characterization method for the transference number of lithium ions in a lithium ion electrolyte, and relates to the technical field of lithium batteries, and the method comprises the following steps: firstly, preparing aluminum lithium alloy powder into slurry, coating the surface of an aluminum foil with the slurry, drying, and cutting to prepare an aluminum lithium pole piece; sequentially placing an aluminum-lithium pole piece, a diaphragm and an aluminum-lithium pole piece on a pole piece fixing table, and dropwise adding electrolyte before and after placing a layer of diaphragm every time; then a circular sealing ring is placed, a sealing ring is pressed down, and a positive electrode pressing ring is covered and is tightened and fixed through a stud; connecting the two ends of the assembled device through an electrode lead to enable the device to be short-circuited, and standing for 6 hours to enable the open-circuit voltage of the device to be balanced to 0V; an electrochemical workstation is used for testing the alternating-current impedance spectrum of the device, and a pre-polarization impedance diagram of the device is obtained; according to the method, the lithium ion transference number of the electrolyte can be simply and quickly analyzed, the performance difference of the lithium ion transmission efficiency of the electrolyte with different formulas can be accurately reflected, and a basis is provided for formula optimization of the electrolyte.

The invention discloses a parallel detection system for a battery alternating current impedance spectrum. The parallel detection system comprises a microcontroller, a plurality of impedance detection chips and a plurality of current control sub-circuits, the current control sub-circuit and the battery to be detected form an excitation loop, and the impedance detection chip is in signal connection with the current control sub-circuit; the plurality of impedance detection chips are sequentially connected in series in a differential communication manner through the daisy chain topology; the first impedance detection chip is in serial communication connection with the microcontroller. On the other hand, the invention discloses a parallel detection method for the alternating-current impedance spectrum of the battery. The parallel detection method comprises the steps of circuit initialization, parameter configuration, synchronous excitation starting, battery response signal collection, same-frequency signal component extraction, complex impedance calculation, data summarization and alternating-current impedance spectrum generation. The frequency division multiplexing (FDM) technology is adopted, excitation and detection of multiple frequency points are carried out at the same time, the EIS measurement time is shortened from the minute level to the second level or even the millisecond level, and the method is particularly suitable for rapid full detection of a battery production line.

The invention relates to the technical field of constructional engineering, and discloses a concrete structure intelligent maintenance method based on multi-point impedance sensing. The invention aims to solve the problems that the existing concrete curing technology depends on experience and cannot sense the spatial non-uniformity of the internal state of the structure in real time, so that the curing measures are blind and the structure quality homogeneity is poor. According to the invention, a plurality of impedance sensors integrated with temperature sensors are arranged in a concrete structure, and AC impedance spectrum data and temperature data at different positions of the structure are synchronously acquired; using a pre-constructed correlation model to solve the current performance index of each monitoring position in real time according to the electrical data subjected to temperature compensation correction; and comparing the calculated performance index with a preset maintenance target, and generating a control instruction to drive a maintenance execution mechanism to carry out partitioned and differentiated maintenance operation on the structure.

The present application relates to the technical field of non-invasive bioelectricity detection, in particular to a non-invasive bioelectricity signal detection method based on flexible sensing technology, which collects the original myoelectricity signal of a target area through a flexible electrode, synchronously acquires the skin micro-deformation amplitude parameter captured by a high-frequency micro-strain sensor, the interface impedance change rate parameter generated by dynamic scanning of alternating current impedance spectrum, and the electrode contact pressure attenuation parameter quantified by a distributed thin film pressure sensor array; inputs the three types of parameters into a dynamic coupling analysis model, generates a real-time contact pressure compensation instruction through a pressure compensation algorithm, generates a signal amplification gain adjustment instruction through a gain adaptive algorithm, and generates a periodic pressure maintenance instruction through a pressure attenuation suppression algorithm, drives a micro pressure actuator and a programmable amplifier according to the instructions, aligns the timing to ensure that the adjustment is completed before the peak period of the myoelectricity signal, and outputs the myoelectricity signal with optimized signal-to-noise ratio, which takes into account the detection accuracy and wearing comfort.

The invention discloses a voltage-sharing electrode impedance measuring and scaling degree judging method, and belongs to the field of voltage-sharing electrode state monitoring of a converter valve cooling system of a high-voltage direct-current transmission system. According to the method, a four-probe difference method is adopted to separate current injection and voltage detection channels, and contact resistance interference is eliminated; the capacitance of the double electric layers is obtained through fitting of a chronoamperometer method and an alternating current impedance spectrum; introducing a temperature and conductivity double-compensation model to correct environmental fluctuation; and establishing a multi-parameter joint discrimination rule of standardized impedance, double-layer capacitance and conduction current. Microohm-level impedance change identification is realized, environmental interference and scaling are effectively distinguished, submillimeter-level initial scaling is stably identified, the state identification accuracy rate reaches 96% or above, online monitoring can be carried out without stopping a converter station, the detection reliability is remarkably improved, and support is provided for safe operation of the converter valve.

The present application relates to the technical field of lithium ion battery, and discloses a method for optimizing compaction density of graphite negative electrode based on relaxation time distribution analysis, which comprises the following steps: preparing dry-state graphite negative electrode base sheets with different gradient compaction densities and assembling them into button-type simulation batteries respectively; performing alternating current impedance spectrum test on the button-type simulation batteries to obtain frequency domain impedance data; using Tikhonov regularization algorithm to deconvolute the frequency domain impedance data and convert it into a relaxation time distribution spectrum diagram with time constant as the abscissa; locating the characteristic peak of a specific time constant interval in the spectrum diagram and performing integration, and extracting the absolute values of charge transfer impedance and diffusion impedance respectively; comparing the above two impedances under different compaction densities, and determining the compaction density corresponding to the common minimum value of the two as the optimal compaction density. The present application overcomes the problem of alternating current impedance polarization semicircle overlap, and quantitatively determines the compaction state in which electronic conduction and ion transport reach balance.

The application discloses a method for collecting and jointly analyzing electrochemical parameters in a corrosion process of a titanium-based material for bipolar plates, and aims at solving the defects of low data correlation in the existing single constant potential polarization and alternating current impedance under constant potential in the corrosion resistance test technology of metal bipolar plates.The method comprises the following steps: 1, placing the titanium-based material for bipolar plates in an electrolyte solution containing H2SO4 and HF, and collecting the alternating current impedance spectrum under bias by using an alternating current impedance measurement program; 2, obtaining the corrosion current density of the impedance data points; 3, drawing a graph of the effective corrosion current density and time in all bias alternating current impedance spectrum measurements; and 4, analyzing the corrosion electrochemical process by the mutation of the effective corrosion current density, the size of the capacitive arc in the Nyquist diagram and the open circuit potential curve.The corrosion resistance of the titanium-based material in the service process can be evaluated by comprehensively analyzing the evolution law of the corrosion current density, the bias impedance and the open circuit potential at the same time.

The invention relates to a method for evaluating the performance of a current drainage device under stray current interference. According to the method, the performance of the current drainage device is comprehensively evaluated by combining laboratory testing, field testing and analogue simulation. A volt-ampere curve and an alternating-current impedance spectrum of the current drainage device are obtained through an electrochemical workstation in a laboratory test, and intrinsic parameters such as conduction voltage, internal resistance and alternating-current impedance of the current drainage device are obtained through fitting. In the field test, direct-current and alternating-current volt-ampere curves are drawn by monitoring drainage quantity and voltage at two ends of the drainage device, performance parameters under actual working conditions are obtained, and changes of pipeline parameters before and after drainage are monitored to verify the protection effect. The simulation module establishes a circuit model according to laboratory and field data, and reproduces and analyzes abnormal volt-ampere characteristics appearing in the field test. According to the method, a closed-loop verification system from intrinsic parameters and actual performance to an internal mechanism is constructed, and comprehensive and quantitative evaluation of the performance of the drainage device is realized.