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30 results about "Ac impedance spectra" patented technology

Corrosion inhibitor performance evaluation device and method of circular cooling water system

The invention discloses a corrosion inhibitor performance evaluation device and method of a circular cooling water system and belongs to the technical field of corrosion inhibitor performance evaluation. In the invention, a circulating water pump is connected with a circular cooling water tank through a pipeline, a heating bar is arranged in the circular cooling water tank, the water inlet of a flow meter is connected with the circulating water pump through a pipeline, the water outlet of the flow meter is connected with the water inlet of a five-opening glass tube through a pipeline, a working electrode, a reference electrode and an auxiliary electrode are respectively arranged on a working electrode opening, a reference electrode opening and an auxiliary electrode opening, the water outlet of the five-opening glass tube is connected with the circular cooling water tank through a pipeline, and the working electrode, the reference electrode and the auxiliary electrode are connected with an electrochemical working station. The device provided by the invention can simulate the flow speed and temperature condition of the circular cooling water under actual working condition, perform AC impedance spectroscopy test on the testing system at the operation state of a testing device, and calculate according to the electrochemical total reaction charge transfer resistance under corrosion inhibitor / non-corrosion inhibitor condition to obtain the corrosion inhibition efficiency of the corrosion inhibitor.
Owner:NANJING UNIV

AC Impedance Spectroscopy Testing of Electrical Parametric Structures

Defects in components in ICs which may cause circuit failures during operation of the IC are often difficult to detect during and immediately after fabrication of the IC by DC test methods. A method of testing components to detect such defects using AC Impedance Spectroscopy is disclosed. Data may be analyzed using Nyquist plots and Bode plots. Nyquist plots of typical defect types are disclosed. Components may include MOS transistor gate structures, contacts, vias and metal interconnect lines. Components tested may be contained in integrated circuits or in test circuits. Integrated circuits containing components tested by AC Impedance Spectroscopy may be partially fabricated or deprocessed after fabrication.
Owner:TEXAS INSTR INC

Lithium ion battery failure analysis method based on alternating current impedance method

The invention provides a lithium ion battery failure analysis method based on an alternating current impedance method. The safety performance of a lithium-ion battery has attracted much attention, anda negative electrode of the lithium ion battery is easily subjected to lithium evolution under the abuse condition, so that a lithium dendritic crystal is formed, and thermal runaway or even explosion of the battery is caused. According to the lithium ion battery failure analysis method based on the alternating current impedance method provided by the invention, an electrochemical alternating current impedance testing method is adopted, a relationship between an alternating current impedance spectrum signal and the internal environment of the battery is analyzed, the SEI film resistance change can be analyzed from an alternating current impedance spectrum, and therefore the state of short circuit in the dendritic crystal of the battery can be quickly and accurately predicted without damaging the battery, thereby evaluating the service life and the safety of the battery.
Owner:BEIHANG UNIV

Method and system for measuring active animal glue concentration in industrial electrolytes

A method consists in measuring ac impedance spectrum using gold, platinum or carbon working ultramicroelectrodes (1). The direct current DC potential pulse which overlaps with alternating current AC signal of an amplitude in the range from 0.005 to 0.015 V and frequency in the range from 10<-2 >to 10<6>, Hz is applied at the electrode. The value of said DC potential pulse for a process of copper electrorefining is in the range from -0.4 to -0.9 V in relation to a platinum reference electrode (2). Resistance values characteristic of a given electrolyte (E) are obtained from said AC impedance spectrum and compared with standard characteristic obtained by standard additions method. A measuring system consist of electrodes (1, 2, 3) placed inside a measuring cell (4) filled with flowing industrial electrolyte. The electrodes (1, 2, 3) are joined to a spectrum analyser (12) controlled by a programming apparatus (13)
Owner:K G H M POLSKA MIEDZ SPOKA AKCYJNA

Lithium ion battery service life estimation method based on alternating-current impedance imaginary part

InactiveCN111537904AImproving Life Estimation AccuracyShorten AC Impedance Test TimeElectrical testingAc impedance spectraEngineering
The invention discloses a lithium ion battery service life estimation method based on an AC impedance imaginary part. The method comprises the following steps: 1) selecting a large number of unaged battery samples, and testing the AC impedance spectrum and capacity value of the battery at different aging stages; 2) calculating a battery AC impedance imaginary part value Z''; 3) establishing a relation table between the battery AC impedance spectrum imaginary part Z'' and the service life under a specific frequency fj according to the test data; and 4) estimating the service life of other batteries with unknown service life according to the relationship between the battery AC impedance imaginary part Z'' and the service life under the specific frequency fj. According to the invention, the service life of the battery is estimated by using the impedance spectrum imaginary part under the specific frequency, and only the impedance test of the battery under the single frequency needs to be performed, so that the AC impedance test time can be greatly shortened, and the service life estimation speed can be effectively improved; and the influence of the contact resistance of the lithium ionbattery on the real part of the impedance spectrum can be eliminated, and the lithium ion battery service life estimation precision can be improved;
Owner:苏州湛云科技有限公司

Method for testing anti-corrosion performance of metallic equipment under island environment

The invention discloses a method for testing anti-corrosion performance of metallic equipment under an island environment. The method specifically comprises the following steps: A, testing a potentiodynamic polarization curve of a metal sample with a coating, and fitting an alternate-current impedance spectrum and a self-corrosion potential of the metal sample with the coating; B, carrying out a salt fog simulation experiment on the metal sample with the coating and recording the corrosion status of the surface of the coating; C, comprehensively evaluating and analyzing the anti-corrosion performance of the metal sample with the coating according to the step A and the step B. According to the method disclosed by the invention, the metallic equipment with the coating is subjected to electrochemical performance testing of the anti-corrosion performance by adopting potentiodynamic polarization and the electrochemical impedance spectrum, and the corrosion process of the metallic equipment with the coating under the island environment is simulated by adopting a salt fog experiment; a most suitable coating of the metallic equipment under different island environments may be selected according to experiment results of the two steps, thereby providing guarantee for reliable operation of a transformer substation.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Hydrogen cell endurance test method

InactiveCN110850320AAccelerated Life TestingElectrical testingFuel cellsAc impedance spectraPtru catalyst
The invention relates to a hydrogen cell endurance test method. The method comprises: coating catalyst slurry on a proton exchange membrane to form a catalyst layer, and then hot-pressing a self-madediffusion layer on both sides of the catalyst layer, to form a membrane electrode; assembling the membrane electrode into a hydrogen cell, and performing single cell activation on the hydrogen cell; collecting a polarization curve of the hydrogen cell before and after open-circuit voltage condition operation; and linearly scanning a voltage-current curve, a sectional view of the catalyst layer anda fluoride concentration according to the polarization curve of the hydrogen cell before and after open-circuit voltage condition operation and an alternating current impedance spectrum, to judge hydrogen cell endurance. According to the hydrogen cell endurance test method, experimental data related to the hydrogen cell is collected, and an attenuation mechanism of a corresponding membrane electrode is analyzed, so as to calculate endurance, namely, a service life of the hydrogen cell, so that hydrogen cell life test can be accelerated, and a hydrogen cell with a long service life is developed.
Owner:HUNAN INST OF METROLOGY & TEST

Accelerated testing system for durability of hydrogen fuel cell

The invention relates to an accelerated testing system for durability of a hydrogen fuel cell. The system comprises a hot press, a fuel cell test module, an impedance meter, an electrochemical workstation, a scanning electron microscope and an ion chromatograph, wherein after catalyst slurry is coated on a proton exchange film to form a catalytic layer, the hot press is suitable for hot-pressing aself-made diffusion layer on two sides of the catalytic layer to form a film electrode, the film electrode is assembled into a hydrogen fuel cell, single cell activation of the hydrogen fuel cell isperformed, and the durability of the hydrogen fuel cell is determined according to a polarization curve, an alternating-current impedance spectrum, a linear scanning voltammetry curve, a sectional view of the catalyst layer and the fluorine ion concentration of the film electrode before and after the hydrogen fuel cell operates under the open-circuit voltage working condition. The system is advantaged in that related experimental data of the hydrogen fuel cell are collected, and attenuation mechanisms of corresponding film electrodes are analyzed, so durability, namely the service life, of thehydrogen fuel cell is calculated, the life test of the hydrogen fuel cell can be accelerated, and the hydrogen fuel cell with long service life is developed.
Owner:CENT SOUTH UNIV +1

Sulfide ore working electrode preparation method, working electrode and research method

ActiveCN112782250ADetermined to formDetermine the growth mechanismMaterial electrochemical variablesAc impedance spectraChalcopyrite
The invention belongs to the technical field of electrochemistry, and particularly relates to a preparation method of a sulfide ore working electrode for measuring an electrochemical signal under a sulfide ore pressure leaching process condition, the sulfide ore working electrode and a method for researching the sulfide ore pressure leaching process by applying the working electrode. The problems that in the prior art, devices and methods for measuring dynamic high-temperature and high-pressure electrochemical signals are lacked, and representativeness is lacked when a natural block electrode is used are solved. The sulfide ore working electrode is formed by pressing carbon powder and mineral powder which are mixed according to a certain proportion by adding an adhesive (PVDF). The chalcopyrite leaching electrochemical mechanism at different temperatures is tested through open-circuit potential testing, polarization curve testing and alternating-current impedance spectroscopy testing technologies; and the number of sub-processes in the leaching process can be distinguished by means of the alternating-current impedance technology, kinetic parameters of all the sub-processes are obtained through methods such as equivalent circuit simulation, and the forming and growing mechanism of the passive film on the surface of the chalcopyrite is determined.
Owner:NORTHEASTERN UNIV

AC impedance spectrum evaluation method for influence of CO2-water-rock interaction on pore throat structure of dense rock

The invention discloses an AC impedance spectrum evaluation method for the influence of CO2-water-rock interaction on a pore throat structure of a dense rock. The method comprises the steps of: firstly, preparing a core, and configuring formation water; then, vacuumizing the core, and saturating the formation water; measuring an initial AC impedance spectrum of the core; placing the core in a holder, and injecting CO2 and the formation water under the formation pressure and temperature; measuring the AC impedance spectrum of the core; and comparing Nyquist maps before and after the CO2-water-rock interaction, fitting an equivalent circuit diagram according to the Nyquist maps, and qualitatively evaluating the influence of the CO2-water-rock reaction on the core according to the change condition of the magnitude of the connected pore resistance in the circuit diagram. By adopting the method disclosed by the invention, the influence of the CO2-water-rock interaction on the pore throat structure of the dense rock can be quickly, accurately and qualitatively evaluated.
Owner:CHINA UNIV OF PETROLEUM (BEIJING)

Fuel cell diagnosis method and diagnosis system

ActiveCN112415413AReduce computational load and complexityAvoid falling into local optimumElectrical testingNonlinear modelNon-linear least squares
The invention provides a fuel cell diagnosis method and a diagnosis system. The diagnosis method comprises the following steps of: injecting synchronous multi-frequency current excitation into a fuelcell; collecting a time domain current excitation signal and a voltage feedback signal of the fuel cell, and calculating alternating current impedance spectrum data under different frequency points; constructing an alternating-current impedance spectrum model of the fuel cell, and converting a nonlinear model equation of the alternating-current impedance spectrum model into a linear model equation; fitting the alternating-current impedance spectrum data and the linear model equation according to a least square method principle to obtain parameter values of the alternating-current impedance spectrum model; acquiring feature vectors of the fuel cell according to the parameter values; classifying the feature vectorsby adopting a fault classification algorithm, and diagnosing the working stateof the fuel cell according to the classification result, fitting the linear model equation to greatly reduce the calculation complexity and the calculation amount. The problems of easy falling into local optimum and low precision due to the adoption of a nonlinear least square fitting method are also avoided.
Owner:SHANGHAI HYDROGEN PROPULSION TECH CO LTD

Battery parameter measurement method, device, equipment, medium and program product

The invention relates to a battery parameter measuring method, device and equipment, a medium and a program product. The method comprises the following steps: acquiring an alternating-current impedance spectrum of the proton exchange membrane fuel cell through an electrochemical measurement instrument by adopting a floating measurement method; fitting the impedance of the equivalent circuit with the alternating current impedance spectrum of the proton exchange membrane fuel cell, and determining the target impedance of the equivalent circuit; and calculating the parameters of the battery according to the target circuit parameters corresponding to the target impedance of the equivalent circuit. By adopting the method, the complete alternating-current impedance spectrum of the proton exchange membrane fuel cell can be obtained, potential interference between an electrochemical measuring instrument and the proton exchange membrane fuel cell can be avoided, and the accuracy of parameter measurement of the proton exchange membrane fuel cell is improved.
Owner:TSINGHUA UNIV

Failure Analysis Method of Li-ion Battery Based on AC Impedance Method

The invention provides a lithium ion battery failure analysis method based on an alternating current impedance method. The safety performance of a lithium-ion battery has attracted much attention, anda negative electrode of the lithium ion battery is easily subjected to lithium evolution under the abuse condition, so that a lithium dendritic crystal is formed, and thermal runaway or even explosion of the battery is caused. According to the lithium ion battery failure analysis method based on the alternating current impedance method provided by the invention, an electrochemical alternating current impedance testing method is adopted, a relationship between an alternating current impedance spectrum signal and the internal environment of the battery is analyzed, the SEI film resistance change can be analyzed from an alternating current impedance spectrum, and therefore the state of short circuit in the dendritic crystal of the battery can be quickly and accurately predicted without damaging the battery, thereby evaluating the service life and the safety of the battery.
Owner:BEIHANG UNIV

Method for preparing and testing ion-polluted Nafion film based on fuel cell catalyst layer

The invention discloses a method for preparing and testing an ion-polluted Nafion film based on a fuel cell catalyst layer, and relates to the field of fuel cell testing. The Nafion solution with theconcentration smaller than 2 wt.% is self-assembled on an interdigital electrode with silicon as a substrate for 12-48 h, taken out, dried in the air and then soaked in an ion exchange solution of nitric acid and cobalt nitrate for 24 h or longer, and the ion-polluted Nafion thin film is obtained. Films with different pollution degrees are obtained by adjusting the solution ratio; and the conductivity change of the Nafion films with different pollution degrees is obtained by using an electrochemical method of an alternating current impedance spectrum. The influence of ionomer pollution causedby catalyst attenuation on proton conduction in the battery is reflected by testing the change of proton conductivity of the films with different pollution degrees. And the relationship is establishedamong the ion exchange solution ratio, the film pollution degree and the film conductivity. The pollution degree of the Nafion ionomer in the battery can be conveniently deduced through the conductivity test result of the battery protons. And development of related research on the attenuation mechanism of the battery after long-time operation is facilitated.
Owner:SHANGHAI JIAO TONG UNIV

Battery discharge depth detection method and system

PendingCN112924879AEliminate the effects ofEliminate the effect of open circuit voltageElectrical testingAc impedance spectraTest battery
The embodiment of the invention discloses a battery discharge depth detection method and system. The battery discharge depth detection method comprises the following steps: discharging a to-be-detected battery according to a preset condition so as to control the to-be-detected battery to have a first state; detecting the open-circuit voltage of the battery to be detected; if the open-circuit voltage of the to-be-detected battery is smaller than a voltage threshold value, obtaining a phase angle of the to-be-detected battery in a preset frequency band based on an alternating-current impedance spectrum of the to-be-detected battery; and determining the residual capacity of the to-be-tested battery based on the phase angle of the preset frequency band and the corresponding relationship between the preset phase angle and the residual capacity. According to the discharge depth detection method provided by the embodiment of the invention, the influence of a passive film is eliminated, the discharge depth of the battery can be accurately evaluated, and the problem that the accurate discharge depth cannot be obtained when the open-circuit voltage of the battery is used for predicting the discharge depth in the prior art is solved.
Owner:武汉昊诚锂电科技股份有限公司

Method and device for detecting internal temperature of battery

The invention provides a method and device for detecting the internal temperature of a battery. The method includes collecting the AC impedance spectrum of the battery; determining the characteristic frequency range according to the AC impedance spectrum of the battery, and screening the impedance parameters that have a monotonic relationship with the temperature from the characteristic frequency range; The impedance parameters that have a monotonic relationship with the temperature and the corresponding relationship with the temperature establish a battery internal temperature detection model, and then obtain the internal temperature of the battery. The battery internal temperature detection method and device provided by the present invention integrate the impedance characteristic parameters of the battery and the internal temperature of the battery to detect the internal temperature of the battery without damaging the battery structure, and have high feasibility and practicability.
Owner:CHINA ELECTRIC POWER RES INST +2

Battery energy storage applicability detection and evaluation method, system and device and storage medium

PendingCN112363074AObjective and true evaluation of energy storage applicabilityObjective and true evaluation of applicabilityTesting electric installations on transportPower batteryAc impedance spectra
The invention discloses a battery energy storage applicability detection and evaluation method, system and device and a storage medium. The method comprises the steps: dividing the SOC full interval of a standard ternary power battery into a plurality of interval segments, carrying out the AC impedance spectrum test in each interval segment, and extracting the charge transfer resistance and diffusion impedance of the standard ternary power battery under different SOCs; extracting charge transfer resistance and diffusion impedance of the retired ternary power battery under different SOCs; and evaluating the energy storage applicability of the retired battery according to the average value of the ratio of the charge transfer resistance of the retired ternary power battery to the charge transfer resistance of the standard ternary power battery under different SOCs and the average value of the ratio of the diffusion impedance of the retired ternary power battery to the diffusion impedanceof the standard ternary power battery under different SOCs. Due to the fact that the dynamic electrochemical impedance of the battery is measured, characteristic parameters of the battery in differentcharge states in the normal charging and discharging process can be truly reflected, and the applicability of the retired battery in the energy storage working condition can be evaluated more objectively and truly.
Owner:CHINA ELECTRIC POWER RES INST +2

A method for improving corrosion resistance of coral concrete structures

The invention discloses a method for improving the corrosion resistance of coral concrete structures, comprising the following steps: step 1, coating epoxy asphalt with anticorrosion performance on the outer surface of steel bars to prepare modified epoxy asphalt coated steel bars; step 2 , form reinforced coral concrete members with different types of steel bars, rust inhibitors, protective layer thicknesses, and concrete strength levels, and then remove the formed members from the formwork, and then expose them to seawater after curing; step 3, conduct electrochemical tests on reinforced coral concrete members , to obtain AC impedance spectra of steel bars in reinforced coral concrete members with different exposure times, and to evaluate the anti-corrosion performance of reinforced coral concrete members under different anti-corrosion measures. The invention provides an anticorrosion method using modified epoxy asphalt coated steel bars in a coral concrete structure, the thickness of the concrete protective layer is at least 5.5 cm, the concrete strength level is C50 and above, and an amino alcohol rust inhibitor is added. Significantly improve the corrosion resistance of coral concrete structures.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Asphalt aging evaluation method based on AC impedance spectrum

The invention discloses an asphalt aging evaluation method based on an AC impedance spectrum, which belongs to the technical field of road engineering. The method comprises the following steps of preparing asphalt samples with different aging degrees and an electrolyte into a mixed solution, testing the impedance value of the mixed solution to obtain AC impedance spectrograms of the asphalt samples with different aging degrees, and using the impedance value for evaluating the aging degree of the asphalt sample. According to different degrees of change of impedance before and after asphalt aging, the AC impedance testing method has the advantages of simplicity in operation, low cost, high testing speed and the like, and the problems that the asphalt aging degree is difficult to determine quickly and the current asphalt aging research method is long in consumed time, poor in the repeatability of experimental results, large inthe amount of required samples and the like can be solved, and a new method is provided for monitoring the aging degree of asphalt.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY

A method, device and medium for testing AC impedance spectroscopy

The invention discloses an alternating-current impedance spectrum testing method and a device and a medium. The method comprises the following steps: outputting a trigger signal so as to apply an excitation current to a tested battery, then, collecting the response voltage of the tested battery; establishing a corresponding battery model according to the excitation current and the response voltage; applying a model excitation current to the battery model for simulation to obtain a model prediction voltage under the frequency, repeating the above process, obtaining corresponding model prediction voltages under model excitation current of different frequencies, finally calculating the model excitation current and the obtained multiple model prediction voltages to obtain battery impedance under multiple frequencies, and further calculating to obtain a battery alternating current impedance spectrum. By applying the technical scheme, the real sampling frequency of the repetition period is reduced, the time for obtaining the alternating-current impedance spectrum is greatly shortened, the detection precision of the alternating-current impedance spectrum is improved, and the anti-interference capability in the test process is enhanced.
Owner:杭州华塑科技股份有限公司

A kind of preparation method of sulfide ore working electrode, working electrode and research method

The invention belongs to the technical field of electrochemistry, and in particular relates to a preparation method of a sulfide ore working electrode used for measuring electrochemical signals under pressure leaching process conditions of sulfide ore, a sulfide ore working electrode, and the application of the working electrode to sulfide ore working electrodes. Methods for the study of pressure leaching processes. It solves the problems of lack of devices and methods for measuring dynamic high temperature and high pressure electrochemical signals and the lack of representativeness of using natural bulk electrodes in the prior art. The sulfide ore working electrode is made of carbon powder and mineral powder mixed in a certain proportion and added with a binder (PVDF). Through the open circuit potential test, polarization curve test and AC impedance spectrum test technology, the electrochemical mechanism of chalcopyrite leaching at different temperatures is tested; with the help of AC impedance technology, the number of sub-processes in the leaching process can be distinguished, and the equivalent circuit simulation The kinetic parameters of each sub-process were obtained by methods such as the following methods, and the formation and growth mechanism of the passivation film on the chalcopyrite surface were determined.
Owner:NORTHEASTERN UNIV LIAONING

Relaxation time distribution-based lithium ion battery modeling method

The invention relates to a relaxation time distribution-based lithium ion battery modeling method. The method comprises the following steps of: S1, carrying out an alternating current impedance spectrum test on a lithium ion battery sample under a specific SOC and temperature T; S2, calculating alternating current impedance; S3, establishing a relaxation time distribution function of the alternating-current impedance by utilizing a Debye relaxation time formula; S4, determining the order of a battery RC model he and each parameter of the model according to the relaxation time distribution function of the alternating-current impedance; and S5, determining a lithium ion battery model. Compared with the prior art, the method eliminate the influence of subjective factors on model establishmentand enables high precision for the established model.
Owner:TONGJI UNIV

A Method for Coating Aging Failure Evaluation in Atmospheric Thin Liquid Film Environment

The invention belongs to the technical field of studies of aging failure of a coating under an atmospheric thin liquid film environment, and relates to a method for evaluating the aging failure of thecoating under the atmospheric thin liquid film environment. A 32-bit ARM and a high-speed ADDA converter are adopted to develop a low-power 8-channel coating aging on-line monitoring instrument, which is mainly used for measuring the protection performance of the aircraft coating to realize multiple measuring methods such as open circuit potential, constant potential polarization and AC impedancespectroscopy. In order to measure the aging state of the coating exposed to the atmospheric environment, a three-electrode impedance monitoring probe based on the same material is developed to achieve the online testing of the aging state of the coating in the atmosphere.
Owner:CHINA SPECIAL TYPE FLIER RES INST

Method and system for predicting electrochemical alternating-current impedance spectrum changing along with fuel cell attenuation

The invention relates to a method and a system for predicting an electrochemical alternating-current impedance spectrum changing along with fuel cell attenuation, and the method comprises the following steps: a data recording step: in a fuel cell attenuation experiment, recording the numerical value change of data to be measured by taking T as a time period; an equation establishment step: establishing an equation of to-be-tested data and attenuation test time; a parameter calculation and verification step: calculating parameters of a verification equation based on the established equation; a to-be-tested data estimation step: estimating the change of the to-be-tested data along with the test time according to the calculated estimated values of the parameters; and a fuel cell electrochemical alternating-current impedance spectrum estimation step: estimating the fuel cell electrochemical alternating-current impedance spectrum based on the estimated to-be-measured data. According to the method, the change of the alternating current impedance spectrum is estimated based on the Bayesian principle and an equivalent circuit model through high-frequency and low-frequency test results accumulated in the attenuation process of the fuel cell. Compared with the prior art, the method is high in precision and high in reliability of calculation results, and meanwhile, the time required for fuel cell life testing can be shortened.
Owner:上海艾福亿维测试设备有限公司

A LIB LIFE ESTIMATION METHOD BASED ON RELAXATION TIME DISTRIBUTION

ActiveCN112327171BEstimated speedImproving Life Estimation AccuracyElectrical testingAc impedance spectraTest battery
The invention relates to a method for estimating the life of a lithium-ion battery based on relaxation time distribution. The method includes the following steps: S1. Select a large number of lithium-ion battery samples that have not been aged, and test the AC impedance spectrum and the AC impedance spectrum of the battery at different aging stages Capacity value; S2. Calculate the relaxation time distribution function of AC impedance; S3. Establish the relationship between the relaxation time distribution function and the life; S4. According to the relationship between the relaxation time distribution and the life at a specific frequency, other batteries with unknown life life expectancy. Compared with the prior art, the invention considers the aging mechanism of the lithium ion battery, and can improve the life estimation accuracy of the lithium ion battery.
Owner:TONGJI UNIV

A modeling method for lithium-ion batteries based on relaxation time distribution

The present invention relates to a lithium-ion battery modeling method based on relaxation time distribution, the method comprising the following steps: S1, performing an AC impedance spectrum test on a lithium-ion battery sample at a specific SOC and temperature T; S2, calculating the AC impedance; S3. Using the Debye relaxation time formula to establish a relaxation time distribution function of the AC impedance; S4. Determine the battery RC model order and model parameters according to the AC impedance relaxation time distribution function; S5. Determine the lithium-ion battery model. Compared with the prior art, the present invention eliminates the influence of subjective factors on model establishment, and the established model has high precision.
Owner:TONGJI UNIV

A method for testing the concentration of chloride ions on the surface of cement-based materials

The invention discloses a method for testing the concentration of chloride ions on the surface of cement-based materials. Two test pieces arranged at intervals are made through an insulating mold and a baffle, and an internal electrode and an external electrode are arranged on each test piece, and the test piece is solidified. , remove the baffle between the two test pieces, so that the mold and the test piece form a cavity between the test pieces, the test sample is obtained after curing to the specified age under the set conditions, and chlorine is added to the cavity of the test sample Ionic solution, using the AC impedance four-point measurement method to test the AC impedance spectrum of the specimen, and calculate the thickness of the adsorption layer on the surface of the specimen, based on the thickness of the adsorption layer, the concentration of chloride ions in the adsorption layer can be obtained, the The concentration is the chloride ion concentration on the surface of the cement-based material. The invention has the advantages of low cost, convenience and quickness, accurate and reliable test results, and is beneficial to the characteristic evaluation of the chloride ion physical adsorption on the concrete surface, the determination of the chloride ion migration coefficient in the concrete, and the more accurate measurement of the durability of the concrete.
Owner:LETS HLDG GRP CO LTD +1

A detection method for the degree of influence of recycled aggregate on the transition zone of concrete interface

The invention relates to a method for detecting the degree of influence of recycled aggregate on the concrete interface transition zone, which is obtained by making a finished test block of recycled aggregate and a finished product test block of acrylic aggregate with conductive properties; and performing an AC impedance spectrum test on the two test blocks. The complex plane plot of the electrochemical impedance, obtained by least squares fitting of the equivalent circuit, R 1 , R 1 * and R 2 , R 2 * ; where R 1 and R 2 are the minimum value and maximum value of the real part of the impedance complex plane diagram of a typical recycled aggregate concrete test block, R 1 * and R 2 * are the minimum value and maximum value of the real part in the impedance complex plane diagram of a typical acrylic concrete test block; the influence factor is calculated by the formula. When the influence factor is larger, it indicates that the recycled aggregate has a greater influence on the interface transition zone, and vice versa . Through the above tests, relatively effective impact test results can be obtained, which can be widely used in the test of the impact of recycled aggregate on the concrete interface transition zone.
Owner:北京时代思动科技有限公司
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