331 results about "Electrochemical impedance spectra" patented technology

The use of electrical impedance spectroscopy to adjust calibration settings in an in vivo monitoring system, such as an in vivo continuous glucose monitoring sensor. The adjustments can compensate for the condition of the sensor membrane in vivo.

The invention provides a parameter obtaining method of a single lithium ion full battery, and belongs to the field of new energy research. The method comprises the following steps that 1) a mathematical electrochemical impedance spectrum model of the lithium ion battery is established; 2) an electrochemical impedance spectrum of the single lithium ion full battery to be measured is measured actually; and 3) according to the established mathematical model, parameters of the actually measured electrochemical impedance spectrum are identified according to frequency ranges, and anode and cathode parameters of the single lithium ion full battery to be measured are obtained. Aimed at the defect that parameters cannot be identified effectively when a present semi-battery model is used for a full battery, characteristics of the electrochemical impedance spectrum of the lithium ion battery are combined, a manner of parameter identification according to the frequency ranges is used, and anode and cathode model parameters of the lithium ion full battery can be obtained rapidly and accurately. The method of the invention can be used for gaining mechanism analysis, SOC estimation and life prediction of the lithium ion battery.

The invention is a method for estimating the internal state of a system for the electrochemical storage of electrical energy, such as a battery. For various internal states of batteries of the same type as a battery being analysed, impedance measurements are carried out by adding an electrical signal to the current passing through the batteries. Then, an RC circuit is used to model the impedances. Next, a relationship is calibrated between the SoC (and/or the SoH) and the parameters of the RC circuit using multivariate statistical analysis. A measurement of the impedance of the battery under analysis is carried out which is modeled using the RC circuit. Finally, the relationship of the equivalent electric circuit defined for the battery being analysed is used to estimate the internal state of that battery.

Concentric bipolar electrode sensors and assemblies provide for and/or facilitate detection and diagnosis of the non-obstructive and pro-inflammatory atherosclerotic lesions in human arteries during catheterization using electrochemical impedance spectroscopy (EIS). Fabrication techniques for concentric bipolar electrode sensors are also described.

A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.

A lithium ion battery internal health feature extraction method based on an impedance spectrum, and relates to the new energy research field; an existing method uses an EIS to analyze and estimate a SOH, wherein the EIS is long in measuring time, and cannot realize online measurements; the lithium ion battery internal health feature extraction method comprises the following steps: building a lithium ion battery electrochemistry impedance spectrum mathematics model; fast measuring a lithium ion battery electrochemistry impedance spectrum, and obtaining the lithium ion battery electrochemistry impedance spectrum; using the lithium ion battery electrochemistry impedance spectrum mathematics model to identify the lithium ion battery electrochemistry impedance spectrum parameters respectively under high, medium and low frequency stages, thus obtaining the lithium ion battery model parameters; periodically measuring the electrochemistry impedance spectrum of the aged lithium ion battery, using the lithium ion battery electrochemistry impedance spectrum mathematics model to identify the lithium ion battery electrochemistry impedance spectrum parameters of the aged lithium ion battery, thus obtaining the model parameter changing rules in the lithium ion battery aging process, and serving as the features that evaluate the battery health states. The lithium ion battery internal health feature extraction method is used for evaluating the battery health states.

The invention discloses an online proton exchange membrane fuel cell fault diagnosis method based on an impedance spectrum. The method includes: Firstly, establishing an electrochemical equivalent circuit model of the proton exchange membrane fuel cell; performing measuring to obtain an electrochemical impedance spectrum of the proton exchange membrane fuel cell; fitting and solving parameters inthe electrochemical equivalent circuit model by using an electrochemical impedance spectrum; and then selecting a part of parameters as classification characteristics, carrying out classification processing on the proton exchange membrane fuel cells by using a fault diagnosis algorithm based on a binary tree support vector machine, and diagnosing faults such as membrane dryness, water logging andair starvation which easily occur in the proton exchange membrane fuel cells. The problem that fault detection is difficult in the operation process of the proton exchange membrane fuel cell is solved, the electrochemical impedance spectroscopy technology is applied to on-line operation monitoring and fault diagnosis of the fuel cell, and the reliability and durability of the cell can be improved.

A method for electrochemical impedance spectroscopy uses interdigitated electrodes functionalized with a first species and nanoparticles functionalized with a second species that preferentially attaches to the first species. The nanoparticles are composed of a material with a dielectric constant (k value) greater than 2. The chemically functionalized electrodes are then exposed to a solution containing the chemically functionalized nanoparticles which then become immobilized on the electrodes through the attachment of the first species to the second species. The impedance spectrum is measured and an amount of the first species is then determined from the measured spectrum. Because the high-k dielectric nanoparticles increase the double-layer capacitive impedance, the sensitivity of determining the amount of the first species attached to the second species is enhanced.

A method and apparatus for determining spatial locations of defects in a material are described. The method includes providing a plurality of electrodes in contact with a material, applying a sinusoidal voltage to a select number of the electrodes at a predetermined frequency, determining gain and phase angle measurements at other of the electrodes in response to applying the sinusoidal voltage to the select number of electrodes, determining impedance values from the gain and phase angle measurements, computing an impedance spectrum for an area of the material from the determined impedance values, and comparing the computed impedance spectrum with a known impedance spectrum to identify spatial locations of defects in the material.

A system and method of use is provided for using electrochemical impedance spectroscopy to determine the corrosion rates of coupled metals. Two dissimilar metals are coupled together and exposed to a saltwater electrolyte in an electrochemical cell. A variable frequency current is passed through the cell and collected at the coupled metals. The impedance and phase angle of the collected current data are plotted verses frequency. The plotted data are compared to and analogized to a known plot for physical electric circuits. When a matching plot and circuit are found, the corrosion rate data associated with the matched plot are used to determine the corrosion rates of the coupled metals.

The invention discloses a molybdenum disulfide diaphragm of a lithium-sulfur battery and a preparation method therefor, belonging to the field of lithium-sulfur batteries. According to the molybdenum disulfide diaphragm of the lithium-sulfur battery, the molybdenum disulfide diaphragm has high lithium conductivity, and is capable of inhibiting the migration of polysulfides between a positive electrode and a negative electrode so as to improve a cycle life of the lithium-sulfur battery. In addition, the high-temperature resistance of molybdenum disulfide is used to improve the overall temperature resistance of the diaphragm; a vacuum filtration method is used to deposit a molybdenum disulfide nanosheet on the surface layer of the lithium-sulfur battery diaphragm; and a relative position of pore size of a funnel on the surface of the molybdenum disulfide diaphragm is relatively small in thickness under the vacuum filtration condition, so that good air permeability can be achieved, and battery capacity is not affected. The MoS2/Celgard prepared is applied to the lithium-sulfur battery; an electrochemical impedance spectroscopy result shows that the lithium ion conductivity of the MoS2/Celgard diaphragm is about 2.0*10<-1> mS.cm<-1>, thereby substantially prolonging the cycle life of the lithium-sulfur battery. The whole preparation method is short in process flows, the conditions are simple, the cost is low, and no pollution is caused to the environment, so that a requirement of cleaner production can be achieved.

A method for retrospective calibration of a glucose sensor uses stored values of measured working electrode current (Isig) to calculate a final sensor glucose (SG) value retrospectively. The Isig values may be preprocessed, discrete wavelet decomposition applied. At least one machine learning model, such as, e.g., Genetic Programming (GP) and Regression Decision Tree (DT), may be used to calculate SG values based on the Isig values and the discrete wavelet decomposition. Other inputs may include, e.g., counter electrode voltage (Vcntr) and Electrochemical Impedance Spectroscopy (EIS) data. A plurality of machine learning models may be used to generate respective SG values, which are then fused to generate a fused SG. Fused SG values may be filtered to smooth the data, and blanked if necessary.

Electrochemical Impedance Spectroscopy (EIS) is used in conjunction with continuous glucose monitors and continuous glucose monitoring (CGM) to enable in-vivo sensor calibration, gross (sensor) failure analysis, and intelligent sensor diagnostics and fault detection. An equivalent circuit model is defined, and circuit elements are used to characterize sensor behavior.

The invention discloses a three-electrode measurement based online monitoring method for electrochemical properties of a positive electrode and a negative electrode of a lithium battery. The method is characterized by comprising steps of 1, selecting appropriate material for assembling a three-electrode measurement device; 2, adopting a charge/discharge testing instrument to connect with the positive electrode and the negative electrode of a three-electrode lithium ion battery separately and performing charge/discharge testing; 3, performing online synchronous monitoring on positive voltage and negative voltage of the lithium ion battery; 4, performing online synchronous electrochemical impedance testing on the lithium ion battery and utilizing an impedance spectroscopy testing instrument to measure the positive electrode and the negative electrode and the electrochemical impedance spectroscopy of the whole battery after the battery is charged or discharged until a stable state is reached. The invention has beneficial effects that the novel testing method capable of collecting electrochemical information of the whole battery, the positive electrode and the negative electrode at the same time is provided and a defect that electrochemical information in the battery cannot be measured accurately by using a current traditional two-electrode testing method for commercial batteries is made up.

A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.

Electrochemical Impedance Spectrum (EIS) data are used directly to predict the pulse performance of an energy storage device. The impedance spectrum of the EIS is obtained in-situ using pre-existing techniques. A simulation waveform is configured such that the period of the pulse is greater than or equal to the lowest frequency of the impedance measurement. If the pulse is assumed to be periodic for analysis purposes, the complex Fourier series coefficients can be obtained. The number of harmonic constituents are selected so as to appropriately resolve the response, but the maximum frequency should be less than or equal to the highest frequency of the impedance measurement. In some cases, the measured frequencies of the impedance spectrum do not match the corresponding harmonic components of the simulated pulse wave. This is resolved by estimating the impedance measurements at the desired frequencies using linear interpolation, cubic spline fits, or other comparable methods. Using a current pulse as an example, the Fourier coefficients of the pulse are multiplied by the impedance spectrum at the corresponding frequency to obtain the Fourier coefficients of the voltage response to the desired pulse. The Fourier coefficients of the response are then summed reassemble to obtain the overall time domain estimate of the voltage using the Fourier series analysis. Thus, the response of an energy storage device to an anticipated or desired pulse can be estimated using low-level, charge neutral impedance measurements combined with Fourier series analysis.

The invention brings forward a sorting method for batteries. The method comprises the following steps: respectively acquiring electrochemical impedance spectrums of n to-be-sorted batteries under a plurality of preset sorting conditions, wherein the preset sorting conditions comprise preset temperature and a preset charged state, and n is a positive integer; acquiring an equivalent circuit model and carrying out fitting on the electrochemical impedance spectrums by using the equivalent circuit model so as to obtain circuit parameter values corresponding to the electrochemical impedance spectrums; screening the plurality of preset sorting conditions according to the electrochemical impedance spectrums and the circuit parameter values so as to obtain a first sorting condition; constructing impedance vectors corresponding to each battery according to the circuit parameter values corresponding to the first sorting condition; and carrying out cluster analysis on the n batteries according to the impedance vectors so as to realize sorting of the n batteries. According to the method provided by embodiments in the invention, the first sorting condition applicable to sorting of lithium ion secondary batteries is screened, then the batteries are sorted according to physical quantity of battery internal information under the first sorting condition, so accuracy of battery sorting is substantially improved.

The invention relates to a rapid evaluation method for the cycle performance of a graphite negative electrode material for a lithium battery. The method is characterized in that rapid evaluation of the cycle performance of the graphite negative electrode material is achieved by using an electrochemical impedance spectroscopy, an all-battery three-electrode test and a capacity increment-based dQ/dV-V curve and combining a local SOC circulation method. The rapid evaluation method has the beneficial effects that the rapid evaluation method has in-situ nondestructive characteristics, and is shortin test period, high in efficiency, low in cost, simple in process, easy to operate and high in reliability; the cycle performance of the battery can be detected without destroying the battery; 40-70%of test time can be shortened; the energy consumption can be greatly reduced and manpower and material resources are greatly saved; the rapid evaluation method can be carried out in a room-temperature environment; complicated conditions are not needed; and compared with a traditional method, the rapid evaluation method has the advantage that the test time is obviously shortened. The rapid evaluation method is applicable to a circular battery, a square battery and a soft package battery, is free of limitation of the size and can be widely applied to massive production; the electric quantity can be significantly saved; the cost can be significantly reduced; and the manpower and material resources are greatly saved.

The invention discloses an on-line measuring device for electrochemical impedance spectroscopy of a lithium ion battery pack, and relates to the field of on-line measurement of electrochemical impedance spectroscopy of the lithium ion battery pack. The device is to solve the existing problems that the electrochemical impedance spectroscopy of the lithium ion battery pack is measured by using an alternating current impedance method, a measuring method requires a dedicated testing device, the testing period is long, and the integration and on-line measurement in a system are difficult to achieve. A processor is used for grouping sine waves of each frequency, and the sine waves of each frequency after grouping are loaded into different sections of a lowest frequency sinusoidal signal; a voltage excitation signal is obtained by a signal generator; an on-off switching circuit makes a lithium ion single battery chosen through switching receive current excitation signals of different sections; a V-I conversion circuit converts voltage excitation signals into the current excitation signals; a sampling circuit obtains response voltage signals of different sections; the processor is also used for conducting fast Fourier transform on the response voltage signals to obtain the impedance spectrum spectroscopy. The device is used for measuring the impedance spectroscopy of the lithium ion battery pack.

A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.

A single, optimal, fused sensor glucose value may be calculated based on respective sensor glucose values of a plurality of redundant working electrodes (WEs) of a glucose sensor. Respective electrochemical impedance spectroscopy (EIS) procedures may be performed for each of the WEs to obtain values of membrane resistance (Rmem) for each WE. A noise value and a calibration factor (CF) value may be calculated for each WE, and respective fusion weights may be calculated for Rmem, noise, and CF for each WE. An overall fusion weight may then be calculated based on the WE's Rmem fusion weight, noise fusion weight, and CF fusion weight, such that a single, optimal, fused sensor glucose value may be calculated based on the respective overall fusion weight and sensor glucose value of each of the plurality of redundant working electrodes.

Disclosed is a method of preparation of corrosion-resistant epoxy coatings. The coating composition contains two main corrosion resistant factors: The first one was Eemeraldine-Base polyaniline (EB-PANi), dissolved in the aminic hardener of epoxy. The other one was montmorrilonite clay, dispersed or exfoliated in the base component of epoxy resin. The hardener composition was prepared via dissolution of EB-PANi in functional amines like 3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine adopting sonication and nanoscale filtering methods. The base component was prepared via gradual charging of MMT clay in epoxy resin via high-shear mixing plus sonication method. The morphology of the coatings during different stages of preparation was studied by optical microscopy and scanning electron microscopy and TEM. The corrosion-protective performance of the resultant coatings was evaluated by electrochemical impedance spectroscopy and salt spray tests. The results were compared with those of conventional epoxy zinc-chromate and neat resin coatings. Superior corrosion resistance was achieved via dissolution of 0.5-2.5 wt % of EB-PANi in the aminic hardener and 2-4 WT % of organomodified MMT in base component of coating.