New energy battery electrochemical impedance spectroscopy test method, device, equipment and medium

Abstract

The invention provides a new energy battery electrochemical impedance spectroscopy test method, device, equipment and medium, and relates to the technical field of new energy battery electrochemical impedance spectroscopy, the method comprises the following steps: processing an output voltage one-dimensional time sequence signal and an output current one-dimensional time sequence signal by using preset generalized S transformation; obtaining an output voltage two-dimensional time-frequency matrix and an output current two-dimensional time-frequency matrix; determining a target frequency response function estimation mode according to the minimum value of the current average noise level and the voltage average noise level; under the condition that the noise is determined to be from the voltage, calculating a weight matrix based on the energy of the measured current signal to obtain a target impedance value; and under the condition that the noise is determined to be from the current, calculating a weight matrix based on measured voltage signal energy to obtain a target impedance value. Effective harmonic information is extracted from a two-dimensional time-frequency matrix based on a frequency response function estimation technology of energy weight, and an electrochemical impedance spectrum is accurately obtained by preferentially considering more contributive frequency components.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical impedance spectroscopy of new energy batteries, and particularly relates to a method, device, equipment and medium for testing the electrochemical impedance spectroscopy of new energy batteries. Background Art

[0002] The principle of electrochemical impedance spectroscopy testing technology is to inject a perturbation into an electrochemical system in a balanced state or under a certain stable DC polarization condition by using a small-amplitude AC excitation signal, and then based on the measured excitation and response, perform signal processing and analysis to study the variation relationship of the AC impedance of the electrochemical system with frequency. Electrochemical impedance spectroscopy can accurately characterize the internal health state and dynamic behavior of the battery, providing key data support for battery performance evaluation and health monitoring.

[0003] Integrating the electrochemical impedance spectroscopy testing function into power electronic devices can achieve online measurement without additional peripheral equipment. At the same time, selecting an excitation signal with rich effective harmonic components can significantly shorten the measurement time and improve the test efficiency. However, the limitations of small impedance values and low signal-to-noise ratios seriously affect the accuracy and stability of impedance measurement. Therefore, improving the anti-noise performance of electrochemical impedance spectroscopy measurement and more efficiently extracting reliable impedance data from noisy signals have become a huge challenge currently faced.

[0004] Currently, there is no technical solution that can solve the above technical problems, and there is no method, device, equipment and medium for testing the electrochemical impedance spectroscopy of new energy batteries. Summary of the Invention

[0005] The present invention provides a method, device, equipment and medium for testing the electrochemical impedance spectroscopy of new energy batteries, which extracts the effective information of the two-dimensional time-frequency matrix based on the energy-weighted frequency response function estimation technology, so as to accurately obtain the electrochemical impedance spectroscopy of new energy batteries.

[0006] In a first aspect, the present invention provides a method for testing the electrochemical impedance spectroscopy of new energy batteries, including: Using a preset generalized S transform to process the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current to obtain the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current; Determining the average current noise level according to the output current signal and the frequency group to be measured, determining the average voltage noise level according to the output voltage signal and the frequency group to be measured, and determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level; When it is determined that the noise comes from the voltage, a weight matrix based on the energy of the measured current signal is calculated, and the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix are processed according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; When it is determined that the noise comes from the current, a weight matrix based on the energy of the measured voltage signal is calculated, and the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix are processed according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

[0007] According to the new energy battery electrochemical impedance spectroscopy test method provided by the present invention, before using the preset generalized S transform to process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal, the method further includes: In the excitation and response stages of the new energy battery electrochemical impedance spectroscopy measurement, the output voltage one-dimensional time series signal and the output current one-dimensional time series signal are collected.

[0008] According to the new energy battery electrochemical impedance spectroscopy test method provided by the present invention, the use of the preset generalized S transform to process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal to obtain the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix includes: ; Wherein, is the output voltage two-dimensional time-frequency matrix, is the output current two-dimensional time-frequency matrix, is the time factor, is the harmonic frequency.

[0009] ; Wherein, and are respectively and the Fourier transform of the Gaussian window function , is the frequency domain variable corresponding to the time domain variable , represents the output voltage one-dimensional time series signal and the output current one-dimensional time series signal, e is the natural constant, j is the imaginary unit, d is the total differential symbol, is the pi.

[0010] According to the new energy battery electrochemical impedance spectroscopy test method provided by the present invention, the determination of the current average noise level according to the output current signal and the set of frequencies to be measured, and the determination of the voltage average noise level according to the output voltage signal and the set of frequencies to be measured includes: The Fourier transform is used to process all output current signals in the frequency group to be measured, obtaining all converted current values. After summing all the converted current values in the frequency group to be measured and taking the average, the average current noise level is obtained; The Fourier transform is used to process all output voltage signals in the frequency group to be measured, obtaining all converted voltage values. After summing all the converted voltage values in the frequency group to be measured and taking the average, the average voltage noise level is obtained.

[0011] According to the new energy battery electrochemical impedance spectrum testing method provided by the present invention, determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level includes: In the case where the average current noise level is less than the average voltage noise level, it is determined that the noise source is voltage; In the case where the average current noise level is greater than the average voltage noise level, it is determined that the noise source is current.

[0012] According to the new energy battery electrochemical impedance spectrum testing method provided by the present invention, calculating the weight matrix based on the energy of the measured current signal and calculating the weight matrix based on the energy of the measured voltage signal includes: ; where, is the weight matrix, is the frequency vector of the signal harmonics, represents the index of the time factor, is the number of moments for impedance calculation, is the m-th moment corresponding to the time factor, is the current, is the voltage, is the frequency response function estimation method based on the current energy weight matrix, is the frequency response function estimation method based on the voltage energy weight matrix.

[0013] According to the new energy battery electrochemical impedance spectrum testing method provided by the present invention, processing the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; processing the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value, includes: ; where, is the target impedance value, is the cross-density spectrum of voltage and current, is the auto-power spectrum of the current, is the auto-power spectrum of the voltage, wherein the cross-density spectrum of the voltage and the current is jointly determined according to the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current, the auto-power spectrum of the current is determined according to the two-dimensional time-frequency matrix of the output current, and the auto-power spectrum of the voltage is determined according to the two-dimensional time-frequency matrix of the output voltage.

[0014] In a second aspect, a new energy battery electrochemical impedance spectrum testing device is provided, including: An acquisition unit, which is used to process the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using a preset generalized S transform to obtain the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current; A determination unit, which is used to determine the average current noise level according to the output current signal and the group of frequencies to be measured, determine the average voltage noise level according to the output voltage signal and the group of frequencies to be measured, and determine the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level; A first calculation unit, which is used to calculate a weight matrix based on the energy of the measured current signal when it is determined that the noise comes from the voltage, and process the weight matrix, the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; A second calculation unit, which is used to calculate a weight matrix based on the energy of the measured voltage signal when it is determined that the noise comes from the current, and process the weight matrix, the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

[0015] In a third aspect, an electronic device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the new energy battery electrochemical impedance spectrum testing method is implemented.

[0016] In a fourth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a calculation program. When the calculation program is executed by a processor, the processor implements the new energy battery electrochemical impedance spectrum testing method.

[0017] The present invention utilizes the generalized S transform to more precisely capture the variation of a signal over time by improving the time resolution. While enhancing the time resolution, it strengthens the retrieval and expression of harmonic information under multiple harmonic components, supports fast calculation, and improves the retrievability and distinguishability of harmonic information. It transforms a one-dimensional time-series signal into a two-dimensional time-frequency matrix, enhancing the expression of harmonic information and enabling more effective processing and analysis of signals with multiple harmonic components. The frequency response function estimation technique based on energy weights extracts effective harmonic information from the two-dimensional time-frequency matrix, and accurately obtains the electrochemical impedance spectrum by preferentially considering more contributive frequency components. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 is one of the schematic flowcharts of the electrochemical impedance spectrum testing method for new energy batteries provided by the present invention; Figure 2 is another schematic flowchart of the electrochemical impedance spectrum testing method for new energy batteries provided by the present invention; Figure 3 is yet another schematic flowchart of the electrochemical impedance spectrum testing method for new energy batteries provided by the present invention; Figure 4 is the electrochemical impedance spectrum result provided by the present invention; Figure 5 is the real part result of the impedance provided by the present invention; Figure 6 is the imaginary part result of the impedance provided by the present invention; Figure 7 is the structural schematic diagram of the electrochemical impedance spectrum testing device for new energy batteries provided by the present invention; Figure 8 is the structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0021] According to the generalized S transform, the present invention transforms a one-dimensional time series including voltage signals and current signals with multiple harmonic components into a two-dimensional time-frequency matrix to enhance the retrievability and distinguishability of harmonic information. For the retrieved information, an electrochemical impedance spectrum is calculated by applying a frequency response function estimation technique based on energy weights.

[0022] Figure 1 FIG. 1 is one of the schematic flowcharts of the electrochemical impedance spectrum testing method for a new energy battery provided by the present invention. The electrochemical impedance spectrum testing method for a new energy battery includes: Step 101: Process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal by using a preset generalized S transform to obtain an output voltage two-dimensional time-frequency matrix and an output current two-dimensional time-frequency matrix; Step 102: Determine the current average noise level according to the output current signal and the group of frequencies to be measured, determine the voltage average noise level according to the output voltage signal and the group of frequencies to be measured, and determine the target frequency response function estimation method according to the minimum value of the current average noise level and the voltage average noise level; Step 103: When it is determined that the noise comes from the voltage, calculate the weight matrix based on the energy of the measured current signal, and process the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; Step 104: When it is determined that the noise comes from the current, calculate the weight matrix based on the energy of the measured voltage signal, and process the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

[0023] In step 101, before processing the output voltage one-dimensional time series signal and the output current one-dimensional time series signal by using a preset generalized S transform, the method further includes: In the excitation and response stages of the electrochemical impedance spectrum measurement of the new energy battery, collect the output voltage one-dimensional time series signal and the output current one-dimensional time series signal.

[0024] Optionally, in the excitation and response stages of the electrochemical impedance spectrum measurement of the new energy battery, collect the voltage one-dimensional time series signal of the battery output voltage and the output current one-dimensional time series signal of the output current. .

[0025] Optionally, the process of using a preset generalized S transform to process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal to obtain an output voltage two-dimensional time-frequency matrix and an output current two-dimensional time-frequency matrix includes: ; Among them, is the two-dimensional time-frequency matrix of the output voltage, is the two-dimensional time-frequency matrix of the output current, is the time factor, is the mathematical form of the generalized S-transform of the harmonic frequency which is given by the following formula:

[0026] Among them, and are respectively and the Fourier transform of the Gaussian window function , is the frequency-domain variable corresponding to the time-domain variable , represents the one-dimensional time-series signal of the output voltage and the one-dimensional time-series signal of the output current. e is the natural constant, j is the imaginary unit, and d is the total differential symbol. is the pi.

[0027] Optionally, the generalized S-transform involved transforms the one-dimensional time-series signal with multiple harmonic components into a two-dimensional time-frequency matrix to enhance the retrievability and distinguishability of harmonic information. The time axis is derived from the time scale of the one-dimensional time series, and the frequency axis corresponds to the effective harmonic components contained in the one-dimensional time series.

[0028] Gaussian window function is determined by the following formula: ; Among them, is the Gaussian window function 's time-domain standard deviation.

[0029] Gaussian window function 's time-domain standard deviation is defined as a function of the frequency : ; Among them, h, p, r are adjustable parameters for controlling the shape.

[0030] Parameter tuning is usually optimized by the degree of energy aggregation, which often involves a huge amount of computation. The principle of selecting the time-domain standard deviation in the present invention is to concentrate the main energy of the Gaussian window to be convolved in the period of the harmonic, and broaden the energy concentration interval to obtain higher time resolution:

[0031] Among them, is a specified energy concentration interval, where n is not less than 3, and it is a parameter measuring the width of the energy concentration interval. To reduce the optimization time to adapt to online applications, tune the hyperparameters h, p, and r according to the settings of the energy concentration interval, and the optimization process is independent of the generalized S-transform.

[0032] The present invention obtains better time resolution by selecting an energy concentration interval of 4 times the time-domain standard deviation: ; where is a specified energy concentration interval, where n is not less than 3, and it is a parameter measuring the width of the energy concentration interval. To reduce the optimization time to adapt to online applications, tune the hyperparameters h, p, and r according to the settings of the energy concentration interval, and the optimization process is independent of the generalized S-transform.

[0033] Furthermore, it can be known that: ; that is , , , and the tuning is independent of the generalized S-transform. It should be noted that in this embodiment, only this one selection scheme is shown to improve the time resolution of the transformation result, and the selection and combination of other parameters also have such effects.

[0034] According to the above formula, the generalized S-transform regards the signal and the exponential term part in the integral term as a whole and introduces a Gaussian window to be convolved, enabling fast operation, thereby reducing the computational complexity:

[0035] where and are respectively and the Fourier transform of the Gaussian window function , is the frequency-domain variable corresponding to the time-domain variable .

[0036] The two-dimensional time-frequency matrix of the output voltage and the output current does not have acceptable accuracy for the information at all times. Calculate the electrochemical impedance spectrum through frequency response function estimation technology. Estimation and estimation are respectively applicable to the cases where the system output noise and the input noise are more obvious. For the new energy battery implementing the electrochemical impedance spectrum measurement, the system input is the output current , and the system output is the output voltage .

[0037] In step 102, determining the current average noise level according to the output current signal and the frequency group to be measured, and determining the voltage average noise level according to the output voltage signal and the frequency group to be measured includes: Use Fourier transform to process all output current signals in the frequency group to be measured, obtain all transformed current values, sum all the transformed current values in the frequency group to be measured, and then take the average value to obtain the current average noise level; Use Fourier transform to process all output voltage signals in the frequency group to be measured, obtain all transformed voltage values, sum all the transformed voltage values in the frequency group to be measured, and then take the average value to obtain the voltage average noise level.

[0038] Optionally, the noise caused by the voltage or current measurement channel and equipment is measured according to the Fourier transform result of the steady-state direct current. In the actual application scenario, it is preferred to measure the stable direct current output current or the output voltage signal, and then obtain and respectively through Fourier transform, and finally calculate the average noise level according to the frequency group to be measured of the electrochemical impedance spectrum : :

[0039] Wherein, is the number of frequencies in the frequency group to be measured . According to the output voltage or the output current with a lower average noise level, select the estimation method of the frequency response function.

[0040] Optionally, determining the target frequency response function estimation method according to the minimum value of the current average noise level and the voltage average noise level includes: When the current average noise level is less than the voltage average noise level, it is determined that the noise comes from the voltage. At this time, select to execute step 103; when the current average noise level is greater than the voltage average noise level, it is determined that the noise comes from the current. At this time, select to execute step 104.

[0041] Optionally, calculating the weight matrix based on the energy of the measured current signal, and calculating the weight matrix when measuring the voltage signal, includes:

[0042] Wherein, is the weight matrix, is the frequency vector of the signal harmonics, represents the index of the time factor, is the number of moments for impedance calculation, is the m-th moment corresponding to the time factor, is the current, is the voltage, is the frequency response function estimation method based on the current energy weight matrix, is the frequency response function estimation method based on the voltage energy weight matrix.

[0043] Optionally, expressing the signal energy as a weight, in the estimation is expressed as the weight matrix of the measured current signal, in the estimation is expressed as the weight matrix of the measured voltage signal. By assigning weights to the cross-power spectrum and auto-power spectrum, the distortion interference of low-energy frequency components on the time axis can be reduced.

[0044] Optionally, processing the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; processing the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the voltage estimation method of the frequency response function based on the voltage energy weight matrix to obtain the target impedance value, including::

[0045] wherein, is the target impedance value, is the cross-density spectrum of voltage and current, is the auto-power spectrum of the current, is the auto-power spectrum of the voltage, is the frequency vector of the signal harmonics, represents the index of the time factor, is the number of moments that can be used for impedance calculation. is the weighting factor of the time-frequency matrix, wherein the cross-density spectrum of voltage and current is jointly determined according to the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix, the auto-power spectrum of the current is determined according to the output current two-dimensional time-frequency matrix, and the auto-power spectrum of the voltage is determined according to the output voltage two-dimensional time-frequency matrix.

[0046] Optionally, the two-dimensional time-frequency matrix of the output voltage and the output current contains information about time and frequency. Due to the distribution difference of signal harmonic power on the time axis and the influence of noise, the information at all moments does not have acceptable accuracy. In order to effectively utilize the limited power in the signal harmonics, the electrochemical impedance spectrum is calculated by the frequency response function estimation technique.

[0047] The main difference between the technical solutions for estimating the frequency response function lies in the assumptions about the source or location of random noise. Estimation and estimation are respectively applicable to the cases where the output noise and input noise are more obvious. According to the output voltage with a relatively low signal-to-noise ratio or output current , the estimation method of the frequency response function is selected. The cross-density spectrum of voltage and current , the auto-power spectrum of current , and the auto-power spectrum of voltage can be calculated respectively by the following formulas:

[0048]

[0049]

[0050] where and are respectively the frequency-domain vectors of the two-dimensional time-frequency matrix and with respect to time , and and are their conjugates respectively.

[0051] Since the time-frequency matrix obtained by the generalized S transform for retrieving impedance information can distinguish the energy information differences, the impedance labeled by frequency can be determined by compressing the time axis. The energy screening problem of the two-dimensional time-frequency matrix with respect to time is converted into a weight representation based on energy, so as to directly perform impedance expression related to frequency characteristics through time-frequency information.

[0052] In an optional embodiment, the electrochemical impedance spectrum of a hydrogen fuel cell is tested online. Due to the characteristics of small impedance values and the influence of noise, in the voltage response obtained by current excitation, each harmonic component has a lower signal-to-noise ratio. For the moment with a time factor of , estimation is selected to calculate the impedance. Estimation and estimation do not avoid the information extraction at a single moment, and the accurate identification of the step moment is still required to improve the calculation accuracy. Since the time-frequency matrix obtained by the generalized S transform for retrieving impedance information can distinguish the energy information differences, the impedance labeled by frequency can be determined by compressing the time axis. The energy screening problem of the two-dimensional time-frequency matrix with respect to time is converted into a weight representation based on energy, so as to directly perform impedance expression related to frequency characteristics through time-frequency information. By assigning weights to the cross-power spectrum and auto-power spectrum, the distortion interference of the frequency components with low energy on the time axis can be reduced. ​

[0053] The present invention utilizes the generalized S - transform to more precisely capture the change of signals over time by improving the time resolution. While enhancing the time resolution, it strengthens the retrieval and expression of harmonic information under multiple harmonic components, supports fast calculation, and improves the retrievability and distinguishability of harmonic information. It transforms the one - dimensional time - series signal into a two - dimensional time - frequency matrix, enhancing the expression of harmonic information and enabling more effective processing and analysis of signals with multiple harmonic components. The frequency - response function estimation technique based on energy weight extracts effective harmonic information from the two - dimensional time - frequency matrix, and accurately obtains the electrochemical impedance spectrum by giving priority to more contributing frequency components.

[0054] Figure 2 It is the second flow schematic diagram of the electrochemical impedance spectrum test method for new - energy batteries provided by the present invention. First, a one - dimensional time - series including the output voltage and output current of the new - energy battery is collected, and then the one - dimensional time - series is transformed into a two - dimensional time - frequency matrix by using the generalized S - transform. Based on the main source of noise, an energy - based weight is designed, and a scheme for the frequency - response function estimation technique is selected according to the main source of noise. Finally, the electrochemical impedance spectrum of the new - energy battery is calculated.

[0055] Figure 3 It is the third flow schematic diagram of the electrochemical impedance spectrum test method for new - energy batteries provided by the present invention. In such an embodiment, the present invention discloses a test method for the electrochemical impedance spectrum of new - energy batteries such as energy - storage batteries, hydrogen fuel cells, and electrolytic cells. In the on - line test stage of the electrochemical impedance spectrum, an excitation superposed with a given working current is input as a reference signal to the current - conversion controller, and a broadband perturbation is implemented by the current excitation to obtain the voltage response at the corresponding frequency. The voltage signal and the current signal are collected as the one - dimensional time - series to be processed in the new - energy battery connected to the current converter. The proposed generalized S - transform transforms the one - dimensional time - series into a two - dimensional time - frequency matrix, effectively improving the time resolution and enabling the retrieval and differentiation of the time - frequency information of multiple harmonic components. Secondly, according to the noise level, the frequency - response function estimation technique based on energy weight is applied to extract the effective information from the two - dimensional time - frequency matrix. The information retrieval and extraction method enhances the adaptability and robustness of impedance acquisition to complex signal environments, and thus improves the measurement accuracy of the electrochemical impedance spectrum.

[0056] Figure 4 It is the result of the electrochemical impedance spectrum provided by the present invention. The information retrieval and extraction method of the embodiment is applied to the calculation of the voltage and current collected during the test process of the electrochemical impedance spectrum of the hydrogen fuel cell. By injecting an excitation current with multiple harmonic components into the hydrogen fuel cell to obtain the response voltage, the current signal and the voltage signal are collected. Figure 4For the electrochemical impedance spectroscopy results obtained based on the proposed method and FFT, compared with the traditional FFT results, the proposed information retrieval and extraction method greatly alleviates the noise interference. While smoothing the electrochemical impedance spectroscopy results, it improves its measurement accuracy. Figure 5 and Figure 6 For the real and imaginary part results of the impedance obtained based on the proposed method and FFT, whether viewed from the comparison of the real part or the imaginary part, the results of the proposed method are smoother and more accurate.

[0057] Figure 7 is a schematic structural diagram of the electrochemical impedance spectroscopy test device for new energy batteries provided by the present invention. The electrochemical impedance spectroscopy test device for new energy batteries includes an acquisition unit 1. The acquisition unit 1 is used to process the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using a preset generalized S transform to obtain a two-dimensional time-frequency matrix of the output voltage and a two-dimensional time-frequency matrix of the output current. The working principle of the acquisition unit 1 can refer to the foregoing step 101 and will not be elaborated here.

[0058] The electrochemical impedance spectroscopy test device for new energy batteries further includes a determination unit 2. The determination unit 2 is used to determine the average current noise level according to the output current signal and the group of frequencies to be measured, determine the average voltage noise level according to the output voltage signal and the group of frequencies to be measured, and determine the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level. The working principle of the determination unit 2 can refer to the foregoing step 102 and will not be elaborated here.

[0059] The electrochemical impedance spectroscopy test device for new energy batteries further includes a first calculation unit 3. The first calculation unit 3 is used to calculate a weight matrix based on the energy of the measured current signal when it is determined that the noise comes from the voltage, and process the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value. The working principle of the first calculation unit 3 can refer to the foregoing step 103 and will not be elaborated here.

[0060] The electrochemical impedance spectroscopy test device for new energy batteries further includes a second calculation unit 4. The second calculation unit 4 is used to calculate a weight matrix based on the energy of the measured voltage signal when it is determined that the noise comes from the current, and process the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the voltage-current energy weight matrix to obtain the target impedance value. The working principle of the second calculation unit 4 can refer to the foregoing step 104 and will not be elaborated here.

[0061] The present invention utilizes the generalized S transform to more finely capture the change of the signal over time by improving the time resolution. While improving the time resolution, it enhances the retrieval expression of harmonic information under multiple harmonic components, supports fast calculation, and improves the retrievability and distinguishability of harmonic information; transforms the one-dimensional time series signal into a two-dimensional time-frequency matrix, enhances the expression of harmonic information, and can more effectively process and analyze signals with multiple harmonic components; extracts effective harmonic information from the two-dimensional time-frequency matrix based on the energy-weighted frequency response function estimation technique, and accurately obtains the electrochemical impedance spectrum by preferentially considering more contributing frequency components.

[0062] Figure 8 is a schematic structural diagram of the electronic device provided by the present invention. As Figure 8 shown, the electronic device may include: a processor 110, a communication interface 120, a memory 130, and a communication bus 140. Among them, the processor 110, the communication interface 120, and the memory 130 complete mutual communication through the communication bus 140. The processor 110 can call the logical instructions in the memory 130 to execute the method for testing the electrochemical impedance spectrum of a new energy battery. The method includes: processing the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using a preset generalized S transform to obtain the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current; determining the average current noise level according to the output current signal and the group of frequencies to be measured, determining the average voltage noise level according to the output voltage signal and the group of frequencies to be measured, and determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level; when it is determined that the noise comes from the voltage, calculating the weight matrix based on the energy of the measured current signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; when it is determined that the noise comes from the current, calculating the weight matrix based on the energy of the measured voltage signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

[0063] In addition, the logical instructions in the above-mentioned memory 130 can be implemented in the form of software functional units. When sold or used independently as a product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0064] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a new energy battery electrochemical impedance spectroscopy testing method provided by the above-mentioned various methods. The method includes: using a preset generalized S transform to process the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current to obtain a two-dimensional time-frequency matrix of the output voltage and a two-dimensional time-frequency matrix of the output current; determining the average current noise level according to the output current signal and the group of frequencies to be measured, determining the average voltage noise level according to the output voltage signal and the group of frequencies to be measured, and determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level; in the case where it is determined that the noise comes from the voltage, calculating a weight matrix based on the energy of the measured current signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; in the case where it is determined that the noise comes from the current, calculating a weight matrix based on the energy of the measured voltage signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value.

[0065] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the new energy battery electrochemical impedance spectroscopy testing method provided by the above-mentioned various methods. The method includes: using a preset generalized S transform to process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal to obtain the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix; determining the current average noise level according to the output current signal and the group of frequencies to be measured, determining the voltage average noise level according to the output voltage signal and the group of frequencies to be measured, and determining the target frequency response function estimation method according to the minimum value of the current average noise level and the voltage average noise level; when it is determined that the noise comes from the voltage, calculating the weight matrix based on the energy of the measured current signal, and processing the weight matrix, the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; when it is determined that the noise comes from the current, calculating the weight matrix based on the energy of the measured voltage signal, and processing the weight matrix, the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

[0066] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0067] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for testing the electrochemical impedance spectrum of a new energy battery, characterized in that Including: Processing the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using a preset generalized S transform to obtain the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current; Determining the average current noise level according to the output current signal and the group of frequencies to be measured, determining the average voltage noise level according to the output voltage signal and the group of frequencies to be measured, and determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level; When it is determined that the noise comes from the voltage, calculating the weight matrix based on the energy of the measured current signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; When it is determined that the noise comes from the current, calculating the weight matrix based on the energy of the measured voltage signal, and processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

2. The method for testing the electrochemical impedance spectrum of a new energy battery according to claim 1, wherein Before processing the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using the preset generalized S transform, the method further includes: Collecting the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current during the excitation and response stages of the electrochemical impedance spectroscopy measurement of the new energy battery.

3. The electrochemical impedance spectroscopy testing method for the new energy battery according to claim 1, wherein The processing the one-dimensional time series signal of the output voltage and the one-dimensional time series signal of the output current by using the preset generalized S transform to obtain the two-dimensional time-frequency matrix of the output voltage and the two-dimensional time-frequency matrix of the output current includes: ； Among them, is the two-dimensional time-frequency matrix of the output voltage, is the two-dimensional time-frequency matrix of the output current, is the time factor, is the harmonic frequency; ； Among them, and are respectively and the Fourier transform of the Gaussian window function . is the frequency-domain variable, corresponding to the time-domain variable . represents the one-dimensional time-series signal of the output voltage and the one-dimensional time-series signal of the output current. e is the natural constant, j is the imaginary unit, and d is the total differential symbol is the pi.

4. The method for testing the electrochemical impedance spectrum of a new energy battery according to claim 1, wherein The determining the average current noise level according to the output current signal and the group of frequencies to be measured, and determining the average voltage noise level according to the output voltage signal and the group of frequencies to be measured includes: Processing all the output current signals in the group of frequencies to be measured by using Fourier transform to obtain all the transformed current values, summing up all the transformed current values in the group of frequencies to be measured, and then taking the average value to obtain the average current noise level; Processing all the output voltage signals in the group of frequencies to be measured by using Fourier transform to obtain all the transformed voltage values, summing up all the transformed voltage values in the group of frequencies to be measured, and then taking the average value to obtain the average voltage noise level.

5. The method for testing the electrochemical impedance spectrum of a new energy battery according to claim 1, characterized in that The determining the target frequency response function estimation method according to the minimum value of the average current noise level and the average voltage noise level includes: When the average current noise level is less than the average voltage noise level, determining that the noise comes from the voltage; When the average current noise level is greater than the average voltage noise level, determining that the noise comes from the current.

6. The method for testing the electrochemical impedance spectrum of a new energy battery according to claim 1, characterized in that, Calculating the weight matrix based on the energy of the measured current signal and calculating the weight matrix based on the energy of the measured voltage signal includes: ； Among them, is the weight matrix, is the frequency vector of the signal harmonics, represents the index of the time factor, is the number of moments for impedance calculation, is the m-th moment corresponding to the time factor, is the current, is the voltage, is the frequency response function estimation method based on the current energy weight matrix, is the frequency response function estimation method based on the voltage energy weight matrix.

7. The method for testing the electrochemical impedance spectrum of a new energy battery according to claim 6, wherein Processing the weight matrix, the two-dimensional time-frequency matrix of the output voltage, and the two-dimensional time-frequency matrix of the output current according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; Processing the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the voltage method of the frequency response function based on the voltage energy weight matrix to obtain the target impedance value, including: ； Wherein, is the target impedance value, is the cross-density spectrum of voltage and current, is the auto-power spectrum of current, is the auto-power spectrum of voltage. Wherein, the cross-density spectrum of voltage and current is jointly determined according to the output voltage two-dimensional time-frequency matrix and the output current two-dimensional time-frequency matrix, the auto-power spectrum of current is determined according to the output current two-dimensional time-frequency matrix, and the auto-power spectrum of voltage is determined according to the output voltage two-dimensional time-frequency matrix.

8. An electrochemical impedance spectroscopy test device for a new energy battery, characterized in that, Including: An acquisition unit configured to use a preset generalized S transform to process the output voltage one-dimensional time series signal and the output current one-dimensional time series signal to obtain an output voltage two-dimensional time-frequency matrix and an output current two-dimensional time-frequency matrix; A determination unit configured to determine the average current noise level according to the output current signal and the frequency group to be measured, determine the average voltage noise level according to the output voltage signal and the frequency group to be measured, and determine the target frequency response function estimation method according to the minimum value between the average current noise level and the average voltage noise level; A first calculation unit configured to calculate the weight matrix based on the energy of the measured current signal when it is determined that the noise comes from the voltage, and process the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the current energy weight matrix to obtain the target impedance value; A second calculation unit configured to calculate the weight matrix based on the energy of the measured voltage signal when it is determined that the noise comes from the current, and process the weight matrix, the output voltage two-dimensional time-frequency matrix, and the output current two-dimensional time-frequency matrix according to the frequency response function estimation method based on the voltage energy weight matrix to obtain the target impedance value.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the new energy battery electrochemical impedance spectrum testing method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a calculation program, and when the calculation program is executed by the processor, the processor implements the new energy battery electrochemical impedance spectrum testing method according to any one of claims 1-7.

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