Excitation signal generation method for online testing of electrochemical impedance spectroscopy of new energy batteries

Abstract

The present invention provides a method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery, which relates to the technical field of electrochemical impedance spectroscopy of new energy batteries. The method comprises: determining the amplitude of an expected Fourier coefficient based on the expected amplitude of a specified frequency of an effective frequency component set and the expected amplitude of an unspecified frequency of an effective frequency component set; repeatedly performing the following steps: determining the expected Fourier coefficient based on the amplitude of the expected Fourier coefficient and the current phase angle to obtain the actual Fourier coefficient, replacing the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient; until a preset number of iterations are completed, outputting an optimized binary sequence, and determining an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery based on the optimized binary sequence. The present invention reduces interference in online testing by covering the effective power at the specified frequency as much as possible and maintaining the consistency of the normalized impedance deviation.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical impedance spectroscopy of new energy batteries, and in particular to a method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries. Background Art

[0002] New energy battery technologies, such as energy storage batteries, hydrogen fuel cells, and electrolyzers, are widely considered to be highly promising components of future energy solutions. These technologies not only contribute to the conversion and storage of clean energy, but also play a key role in reducing environmental pollution and promoting sustainable development. However, the performance and lifespan of new energy batteries are significantly affected by their dynamic operating conditions and component durability. Prolonged use and environmental factors such as temperature and load changes can lead to performance degradation and even failure. Electrochemical impedance spectroscopy is a core technology for real-time diagnosis and health prediction of new energy batteries. By conducting in-situ measurements to study the relationship between the AC impedance of the electrochemical system and frequency, potential performance degradation factors and failure modes can be identified.

[0003] Electrochemical impedance spectroscopy (EIS) is typically acquired offline using a frequency sweep technique. Although the results are relatively accurate, the measurements are time-consuming and lack real-time performance. By integrating EIS functionality into power electronics, online measurements can be achieved without the need for external equipment. Simultaneously, selecting an excitation signal with rich, effective harmonic components can shorten measurement time. However, the low impedance characteristics of new energy batteries and the low signal-to-noise ratio caused by electromagnetic interference during online measurements severely impact the impedance measurement accuracy. The limited power of the excitation signal further exacerbates the noise interference with EIS.

[0004] However, there is currently no technical solution that can solve the above technical problems, and there is no method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries. Summary of the Invention

[0005] The present invention provides a method for generating excitation signals for online testing of electrochemical impedance spectroscopy of new energy batteries. The method designs and optimizes a binary sequence based on a set of effective frequency components. In a binary sequence signal of finite length, power is concentrated and distributed for the effective frequency components, thereby achieving high-precision and fast online testing of electrochemical impedance spectroscopy of new energy batteries.

[0006] In a first aspect, the present invention provides a method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery, comprising:

[0007] Determine an expected amplitude of a specified frequency of the effective frequency component set according to the voltage noise component and the priori impedance, and determine an amplitude of an expected Fourier coefficient according to the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set;

[0008] Repeat the following steps:

[0009] Determine the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, perform an inverse discrete Fourier transform on the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, perform an inverse discrete Fourier transform on the binary sequence to obtain an actual Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient;

[0010] Until a preset number of iterations are performed, an optimized binary sequence is output, and an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is determined according to the optimized binary sequence, so as to determine an electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

[0011] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, before determining the expected amplitude of a specified frequency of the effective frequency component set based on the voltage noise component and the priori impedance, the method further includes:

[0012] Based on the typical amplitude-frequency response of new energy batteries, determine the distribution and number of specified harmonics of the defined effective frequency component set at a preset impedance resolution;

[0013] Determining the a priori impedance based on the low-frequency resistance measurement value, the high-frequency resistance measurement value, and a linear relationship between the low-frequency resistance measurement value and the high-frequency resistance measurement value;

[0014] The voltage noise component is determined according to low-frequency noise, band-limited white noise, and spectrum peak narrowband noise.

[0015] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, determining the expected amplitude of a specified frequency of an effective frequency component set based on a voltage noise component and a priori impedance includes:

[0016]

[0017] in, specifies the expected amplitude of the frequencies for the set of valid frequency components, is the a priori impedance, is the voltage noise component, is the normalization term.

[0018] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, after replacing the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient, the method further includes:

[0019] Initialize the optimal power allocation adaptability to positive infinity, set the first convergence threshold, the second convergence threshold, and the first-order difference step size of the indicator, and repeat the following steps:

[0020] Calculating the effective power ratio, and when the effective power ratio at the first-order difference step size is less than the first convergence threshold, calculating the current power allocation adaptability;

[0021] When the current power allocation adaptability is less than the previous power allocation adaptability, updating the optimal power allocation adaptability and the current binary sequence;

[0022] Until the optimal power allocation adaptability is less than the second convergence threshold, the current phase angle is randomly updated.

[0023] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, after calculating the effective power ratio, the method further includes:

[0024] When the effective power ratio under the first-order difference step is greater than or equal to the first convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0025] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, after calculating the current power distribution adaptability, the method further includes:

[0026] When the current power allocation adaptability is greater than or equal to the previous power allocation adaptability, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0027] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, after updating the optimal power allocation adaptability and the current binary sequence, the method further includes:

[0028] When the optimal power allocation adaptability is greater than or equal to the second convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0029] According to the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention, the output optimized binary sequence includes:

[0030]

[0031] in, For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the specified frequency of the effective frequency component set. For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the non-specified frequency of the effective frequency component set. is the actual signal component amplitude of the frequency specified by the effective frequency component set EFCS, k is the harmonic order of the signal at a fixed frequency resolution, and e is a natural constant. is the imaginary unit, Specifies the phase of the frequency for the effective frequency component set EFCS.

[0032] In a second aspect, a device for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is provided, comprising:

[0033] a determining unit, the determining unit being configured to determine an expected amplitude of a specified frequency of the effective frequency component set based on the voltage noise component and the priori impedance, and to determine an amplitude of an expected Fourier coefficient based on the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set;

[0034] A repeating unit, wherein the repeating unit is used to repeatedly perform the following steps:

[0035] Determine the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, perform inverse discrete Fourier transform on the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, perform inverse discrete Fourier transform on the binary sequence to obtain an actual Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient, until a preset number of iterations are performed;

[0036] An output unit is used to output an optimized binary sequence, determine an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to the optimized binary sequence, and determine an electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

[0037] In a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is implemented.

[0038] The present invention determines the harmonic composition of an optimized binary sequence by defining a set of effective frequency components and provides an iterative process for generating the optimized binary sequence using an inverse generation method. Indicators that measure the characteristics of the effective frequency component set are used to screen the optimized binary sequence. The designed signal, while having multiple frequency components, reduces interference during online testing by maximizing effective power coverage within the specified frequency and maintaining consistency in normalized impedance deviation. In electrochemical impedance spectroscopy measurements of new energy batteries, the optimized binary sequence excitation signal designed by the present invention can inject harmonics of multiple frequency components in a short period of time while maintaining consistency in impedance deviation, enabling high-precision and rapid online testing of electrochemical impedance spectroscopy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 This is one of the flow charts of the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention;

[0041] Figure 2 This is the second flow chart of the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention;

[0042] Figure 3 It is a schematic diagram of the steps for optimizing binary sequence design;

[0043] Figure 4 This is a typical amplitude-frequency response diagram of a hydrogen fuel cell under linear-logarithmic-linear distribution;

[0044] Figure 5 This is the estimated result diagram of voltage noise;

[0045] Figure 6 is a graph of iterative steps for optimizing a binary sequence;

[0046] Figure 7 is a diagram of the screening steps for optimizing a binary sequence;

[0047] Figure 8It is the time domain and frequency domain waveform diagram of the optimized binary sequence;

[0048] Figure 9 is the electrochemical impedance spectroscopy result diagram;

[0049] Figure 10 This is a schematic structural diagram of an excitation signal generating device for online electrochemical impedance spectroscopy testing of new energy batteries provided by the present invention;

[0050] Figure 11 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0052] Figure 1 This is one of the flow diagrams of the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the present invention. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery includes:

[0053] Step 101: determining an expected amplitude of a specified frequency of an effective frequency component set according to a voltage noise component and a priori impedance, and determining an amplitude of an expected Fourier coefficient according to the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set;

[0054] Repeat the following steps:

[0055] Step 102: Determine the expected Fourier coefficient based on the amplitude of the expected Fourier coefficient and the current phase angle, perform an inverse discrete Fourier transform on the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, perform an inverse discrete Fourier transform on the binary sequence to obtain an actual Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0056] Step 103 : until a preset number of iterations are performed, an optimized binary sequence is output, and an excitation signal for online electrochemical impedance spectroscopy testing of a new energy battery is determined according to the optimized binary sequence, so as to determine an electrochemical impedance spectrum according to the excitation signal for online electrochemical impedance spectroscopy testing of a new energy battery.

[0057] In step 101, this embodiment provides a method for designing an excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries such as energy storage batteries, hydrogen fuel cells, and electrolytic cells. Figure 2 This is the second flow chart of the method for generating excitation signals for online testing of electrochemical impedance spectroscopy of new energy batteries provided by the present invention. First, based on the prior impedance and battery voltage noise, a quantitative relationship between the expected frequency domain amplitude and measurement accuracy of the optimized binary sequence is established, and then the distribution, quantity and amplitude and other characteristics of the effective frequency component set are designed; secondly, based on the effective power ratio and power allocation adaptability index under the signal optimization target, the inverse generation method is applied to generate an optimized binary sequence with the expected effective frequency component set characteristics, which is used as the excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries, superimposed with the given working current, and used as the input of the converter controller as a whole, thereby implementing broadband perturbation on the converter, exciting a response voltage of the corresponding frequency, and obtaining the electrochemical impedance spectrum by measuring the voltage and current signals.

[0058] Specifically, before determining the expected amplitude of the specified frequency of the effective frequency component set according to the voltage noise component and the a priori impedance, the method further includes:

[0059] Based on the typical amplitude-frequency response of new energy batteries, determine the distribution and number of specified harmonics of the defined effective frequency component set at a preset impedance resolution;

[0060] Determining the a priori impedance based on the low-frequency resistance measurement value, the high-frequency resistance measurement value, and a linear relationship between the low-frequency resistance measurement value and the high-frequency resistance measurement value;

[0061] The voltage noise component is determined according to low-frequency noise, band-limited white noise, and spectrum peak narrowband noise.

[0062] Optionally, based on the prior impedance and noise estimates, the amplitude of the specified harmonics of the defined effective frequency component set is determined while maintaining the consistency of the normalized impedance deviation. Figure 4 This is a typical amplitude-frequency response diagram of a hydrogen fuel cell under linear-logarithmic-linear distribution. and The frequency intervals are The lower and upper bounds of the frequency band 、 and Corresponding to linear, logarithmic and linear distribution respectively. The number of frequencies specified in the effective frequency component set is determined according to the distribution premise. Under the logarithmic distribution, the impedance of the measured object changes significantly with frequency, and several effective frequency points are selected for each decade; under the linear distribution, the impedance does not change much, and sparse frequency points are selected. The distribution and number of the designed effective frequency component set can cope with significant changes in the amplitude-frequency curve while reducing signal complexity. In this embodiment, the frequency band that conforms to the logarithmic distribution Select 10 valid frequency points, which are consistent with the linear distribution frequency band and Select 3 frequency points.

[0063] The amplitude of the specified frequency of the effective frequency component set is determined by maintaining the consistency of the normalized impedance deviation, and the normalized impedance deviation is established. The expression for the expected amplitude Relationship with measurement accuracy:

[0064] ;

[0065] in, is the specified frequency of the set of valid frequency components, and are the measured impedance and the actual impedance, and are the noise-free voltage and current harmonics, and The voltage and current noise components corresponding to the specified frequency of the effective frequency component set are involved. and The existence of random phase makes the normalized impedance deviation There are maximum and minimum values. In order to avoid their uncertainty, the normalized deviation expectation under the complex noise distribution is simplified by using the uniform distribution that conforms to the maximum entropy principle. Express:

[0066] ;

[0067] Maintaining the expected consistency of the normalized impedance deviation is to define it as a constant to determine the expected amplitude of the effective frequency component set at a specified frequency. , the step of determining the expected amplitude of the specified frequency of the effective frequency component set according to the voltage noise component and the priori impedance includes:

[0068] ;

[0069] in, specifies the expected amplitude of the frequencies for the set of valid frequency components, is the a priori impedance, is the voltage noise component, is the normalization term.

[0070] The expected amplitudes of the non-specified frequencies of the effective frequency component set are set to 0:

[0071] ;

[0072] in, is the harmonic order of the signal at a fixed frequency resolution, EFCS refers to the effective frequency component set, It is the frequency component of the actual signal at a fixed frequency resolution, including the specified frequency and other frequencies of the effective frequency component set. It is unknown before the electrochemical impedance spectroscopy measurement. Instead, the voltage noise component Estimated from actual noise measurements.

[0073] Optionally, the a priori impedance is differentiated based on the linear-log-linear distribution of the set of effective frequency components, and The a priori impedance of the frequency band is composed of the low frequency resistance and high frequency resistors The measured value is replaced by The a priori impedance of the frequency band is constructed from the linear relationship between the two:

[0074] ;

[0075] Modeling of three main types of noise including low-frequency 1 / f noise, band-limited white noise and spectrum peak narrowband noise is applied to the voltage noise component. Estimates.

[0076] The random process of the 1 / f noise is expressed as:

[0077] ;

[0078] in, is the cutoff frequency for distinguishing the dominant noise, and A more generalized form of 1 / f noise is described. The generalized parameters use a least-squares solution based on the voltage noise below the cutoff frequency to determine the noise estimate at a specified frequency for the optimized binary sequence.

[0079] The time domain form of the band-limited white noise is approximately a zero-mean Gaussian distribution, the real and imaginary parts of the harmonic components in the frequency domain conform to independent and identically distributed Gaussian distributions, and the amplitude conforms to independent and identically distributed Rayleigh distributions. The frequency domain window, the Rayleigh distribution of the harmonic amplitude, the size parameter According to the maximum likelihood estimation:

[0080]

[0081] in is the harmonic order of the signal at a fixed frequency resolution.

[0082] According to the size parameters Get the mean estimate of the band-limited white noise:

[0083] ;

[0084] The spectral peak narrowband noise is based on the Rayleigh distribution of band-limited white noise at the probability threshold Outliers under Positioning and estimation are performed, and the spectrum peak narrowband noise is estimated to be the actual measurement value by correcting the original mean. Expressed as:

[0085] ;

[0086] 1 / f noise is used to estimate the noise level in the region below the cutoff frequency, and band-limited white noise and spectral peak narrowband noise are used to estimate the noise level in the region above the cutoff frequency.

[0087] The voltage noise estimation is performed according to three cases:

[0088] .

[0089] Figure 5 This is the estimated result of the voltage noise. In this embodiment, the boundary frequency The frequency is selected as 50 Hz and p is 0.95. The spectral peak narrowband noise is clearly distinguished from the 1 / f noise and the band-limited white noise floor. The estimated results of the other specified harmonics are reasonable compared with the actual noise.

[0090] The present invention repeats step 102 until a preset number of iterations are performed, and then executes step 103 to output an optimized binary sequence. An excitation signal for online testing of an electrochemical impedance spectrum of a new energy battery is determined based on the optimized binary sequence, so as to determine an electrochemical impedance spectrum based on the excitation signal for online testing of an electrochemical impedance spectrum of a new energy battery.

[0091] Figure 3 It is a schematic diagram of the design steps of an optimized binary sequence. The present invention specifies the distribution, number and amplitude of harmonics according to the defined effective frequency component set, and iteratively generates an optimized binary sequence based on the inverse generation method. The generated optimized binary sequence is expressed in the time domain as the numerical values ​​of "-1" and "1" of the basic unit. The actual amplitude is proportionally adjusted according to the trade-off between the linear condition of the measurement and the accuracy. The frequency domain effective power of the sequence is concentrated and proportionally distributed in the expected harmonics. The distribution of the frequencies specified by the effective frequency component set conforms to the linear-logarithmic-linear distribution and the frequency bands are separated by the boundaries of ten-fold frequency intervals. Based on the effective frequency component set determined in step S1.1, the time domain form of a discrete binary signal of a given length is arbitrarily initialized, and the corresponding frequency domain expression is re-specified as the expected amplitudes of the specified frequencies and non-specified frequencies of the effective frequency component set. , which is the expected Fourier coefficient The amplitude of As the phase angle of the Fourier coefficient L. Generate the optimized binary sequence by the inverse generation method. Before the iterative loop, initialize the discrete signal period T, the number of iterations L, according to the optimization index; for step S1.2, see Figure 6 The iterative steps shown are cyclically iterated to obtain the optimized binary sequence.

[0092] Figure 6 is an iterative step diagram for optimizing a binary sequence. In step S2.1, the desired Fourier coefficients are inversely discrete Fourier transformed. , and get the time domain signal ;

[0093] ;

[0094] in, is the harmonic order of the signal at a fixed frequency resolution, is the length of the discrete binary signal.

[0095] In step S2.2, the time domain signal is binarized , and get the binary sequence ;

[0096] ;

[0097] In step S2.3, the binary sequence is discrete Fourier transformed , and get the actual Fourier coefficients :

[0098] ;

[0099] in, is the harmonic order of the signal at a fixed frequency resolution, is the length of the discrete binary signal.

[0100] In step S2.4, the expected Fourier coefficients The phase angle is replaced by the actual Fourier coefficient The optimization goal of the iterative loop is to concentrate as much power as possible on the effective frequency component set while meeting its power allocation requirements, as shown in the formula.

[0101] ;

[0102] in, is the harmonic order of the signal at a fixed frequency resolution, is the length of the discrete binary signal, EFCS refers to the effective frequency component set, and constant is an arbitrary fixed constant.

[0103] The optimization objective can be converted into a quantitative evaluation of two indicators: effective power ratio and power allocation adaptability. Effective power ratio measures the power concentration of the optimized binary sequence. iterations, the binary sequence The effective power ratio is expressed as:

[0104] ;

[0105] in, is the power of the specified harmonic, is the total power. is the harmonic order of the signal at a fixed frequency resolution, is the length of the binary sequence, and EFCS refers to the effective frequency component set. Through phase update adjustment, the effective power ratio gradually increases until it converges to the maximum value.

[0106] Optionally, the power distribution adaptability measures the difference between the actual and expected power distributions in the effective harmonic components of the optimized binary sequence, and is defined as:

[0107] ;

[0108] in, Indicates the number of EFCS specified harmonics. yes and The power allocation adaptability ranges from zero to positive infinity. The smaller the value, the more consistent the amplitude of the specified frequency of the effective frequency component set in the binary sequence is with the expected amplitude ratio. In this embodiment, the fixed frequency resolution is 0.1Hz, and the length of the binary sequence is 1×10 6 .

[0109] Optionally, after replacing the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient, the method further includes:

[0110] Initialize the optimal power allocation adaptability to positive infinity, set the first convergence threshold, the second convergence threshold, and the first-order difference step size of the indicator, and repeat the following steps:

[0111] Calculating the effective power ratio, and when the effective power ratio at the first-order difference step size is less than the first convergence threshold, calculating the current power allocation adaptability;

[0112] When the current power allocation adaptability is less than the previous power allocation adaptability, updating the optimal power allocation adaptability and the current binary sequence;

[0113] Until the optimal power allocation adaptability is less than the second convergence threshold, the current phase angle is randomly updated.

[0114] Optionally, after calculating the effective power ratio, the method further includes:

[0115] When the effective power ratio under the first-order difference step is greater than or equal to the first convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0116] Optionally, after calculating the current power allocation adaptability, the method further includes:

[0117] When the current power allocation adaptability is greater than or equal to the previous power allocation adaptability, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0118] Optionally, after updating the optimal power allocation adaptability and the current binary sequence, the method further includes:

[0119] When the optimal power allocation adaptability is greater than or equal to the second convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

[0120] In an optional embodiment, Figure 7 It is a diagram of the screening steps for optimizing binary sequences. After each cycle of steps S2.1 to S2.4, as shown in Figure 5 As shown, the screening steps for optimizing binary sequences are as follows:

[0121] S3.1 Initialize optimal power allocation adaptability is positive infinity, setting the convergence threshold and , and the first-order difference step size a of the indicator;

[0122] S3.2 Calculate the effective power ratio. If the effective power ratio under the first-order difference step size a is less than its threshold , then execute S3.3, otherwise jump out of this step and execute S2.1 to S2.4;

[0123] S3.3 Calculate the power allocation adaptability. If a better power allocation adaptability is obtained, execute S3.4. Otherwise, skip this step and execute S2.1 to S2.4.

[0124] S3.4 Update the optimal power allocation adaptability And binary sequence, if the first-order difference step size The power allocation adaptability under the condition is less than its threshold , then execute S3.5, otherwise jump out of this step and execute S2.1 to S2.4;

[0125] S3.5 randomly updates the phase to avoid falling into the local optimal solution, and jumps out of the step to execute S2.1 to S2.4.

[0126] After the number of iterations meets the preset number of iterations L, the harmonic phase corresponding to the optimal power allocation adaptability under the optimal effective power ratio is updated, and then the optimized binary sequence is calculated.

[0127] By approaching the optimization goal and improving the index performance, the frequency domain form of the optimized binary sequence can be expressed as follows: The output optimized binary sequence includes:

[0128] ;

[0129] in, For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the specified frequency of the effective frequency component set. For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the non-specified frequency of the effective frequency component set. is the actual signal component amplitude of the frequency specified by the effective frequency component set EFCS, which can be proportionally adjusted according to the amplitude proportional adjustment of the binary sequence time domain form in step S1.3, is the harmonic order of the signal at a fixed frequency resolution, is a natural constant, is the imaginary unit, Specifies the phase of the frequency for the effective frequency component set EFCS.

[0130] Figure 8It is a waveform diagram of the time domain and frequency domain of the optimized binary sequence. In order to optimize the time domain and frequency domain waveforms of the binary sequence, the main harmonics in the frequency domain are the specified harmonics of the effective frequency component set. Inevitably, there is a small amount of power waste. This problem has been improved under the indicator of effective power ratio. In addition, the harmonics of the optimized binary sequence are significantly different due to the difference in noise and impedance, so as to achieve the above-mentioned consistency of maintaining the normalized impedance deviation at the specified frequency of the effective frequency component set. The optimized binary sequence of the embodiment is applied to the test of the electrochemical impedance spectrum of hydrogen fuel cells, which is injected into the hydrogen fuel cell as an excitation current, and the sampled battery voltage and current signals are subjected to FFT fast Fourier transform to calculate the impedance at the specified harmonic frequency of the effective frequency component set. Figure 9 is the electrochemical impedance spectroscopy result graph, the convergence threshold and 5×10 -5 and 1×10 -10 , the number of iterations is 3000, and the first-order difference step size is 5.

[0131] The present invention determines the harmonic composition of an optimized binary sequence by defining a set of effective frequency components and provides an iterative process for generating the optimized binary sequence using an inverse generation method. Indicators that measure the characteristics of the effective frequency component set are used to screen the optimized binary sequence. The designed signal, while having multiple frequency components, reduces interference during online testing by maximizing effective power coverage within the specified frequency and maintaining consistency in normalized impedance deviation. In electrochemical impedance spectroscopy measurements of new energy batteries, the optimized binary sequence excitation signal designed by the present invention can inject harmonics of multiple frequency components in a short period of time while maintaining consistency in impedance deviation, enabling high-precision and rapid online testing of electrochemical impedance spectroscopy.

[0132] Figure 10 It is a structural schematic diagram of an excitation signal generating device for online testing of electrochemical impedance spectroscopy of new energy batteries provided by the present invention. The excitation signal generating device for online testing of electrochemical impedance spectroscopy of new energy batteries includes a determination unit 1. The determination unit 1 is used to determine the expected amplitude of the specified frequency of the effective frequency component set based on the voltage noise component and the priori impedance, and to determine the amplitude of the expected Fourier coefficient based on the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of the non-specified frequency of the effective frequency component set. The working principle of the determination unit 1 can be referred to the aforementioned step 101 and will not be repeated here.

[0133] The excitation signal generating device for online testing of electrochemical impedance spectroscopy of new energy batteries further includes a repeating unit 2, which is configured to repeatedly perform the following steps:

[0134] The expected Fourier coefficient is determined according to the amplitude of the expected Fourier coefficient and the current phase angle, the expected Fourier coefficient is inversely discrete Fourier transformed to obtain a time domain signal, the time domain signal is binarized to obtain a binary sequence, the binary sequence is inversely discrete Fourier transformed to obtain the actual Fourier coefficient, and the current phase angle of the expected Fourier coefficient is replaced with the actual phase angle of the actual Fourier coefficient, until the preset number of iterations is performed. The working principle of the repetitive unit 2 can refer to the aforementioned step 102 and will not be repeated here.

[0135] The excitation signal generating device for online testing of electrochemical impedance spectroscopy of new energy batteries also includes an output unit 3, which is used to output an optimized binary sequence, determine the excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries according to the optimized binary sequence, and determine the electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries. The working principle of the output unit 3 can be referred to the aforementioned step 103 and will not be repeated here.

[0136] The present invention determines the harmonic composition of an optimized binary sequence by defining a set of effective frequency components and provides an iterative process for generating the optimized binary sequence using an inverse generation method. Indicators that measure the characteristics of the effective frequency component set are used to screen the optimized binary sequence. The designed signal, while having multiple frequency components, reduces interference during online testing by maximizing effective power coverage within the specified frequency and maintaining consistency in normalized impedance deviation. In electrochemical impedance spectroscopy measurements of new energy batteries, the optimized binary sequence excitation signal designed by the present invention can inject harmonics of multiple frequency components in a short period of time while maintaining consistency in impedance deviation, enabling high-precision and rapid online testing of electrochemical impedance spectroscopy.

[0137] Figure 11 Schematic diagram of the structure of the electronic device provided by the present invention. Figure 11As shown, the electronic device may include: a processor 110 , a communications interface 120 , a memory 130 and a communication bus 140 , wherein the processor 110 , the communications interface 120 and the memory 130 communicate with each other via the communication bus 140 . The processor 110 can call the logic instructions in the memory 130 to execute the excitation signal generation method for online testing of electrochemical impedance spectroscopy of new energy batteries, the method including: determining the expected amplitude of the specified frequency of the effective frequency component set according to the voltage noise component and the prior impedance, and determining the amplitude of the expected Fourier coefficient according to the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of the non-specified frequency of the effective frequency component set; repeatedly performing the following steps: determining the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, inversely discrete Fourier transforming the expected Fourier coefficient to obtain a time domain signal, binarizing the time domain signal to obtain a binary sequence, inversely discrete Fourier transforming the binary sequence to obtain an actual Fourier coefficient, replacing the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient; until a preset number of iterations are performed, an optimized binary sequence is output, and an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is determined according to the optimized binary sequence, so as to determine the electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

[0138] In addition, the logical instructions in the aforementioned memory 130 can be implemented in the form of software functional units and, when sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the 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, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0139] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program 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 method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery provided by the above methods. The method includes: determining the expected amplitude of the specified frequency of the effective frequency component set based on the voltage noise component and the prior impedance, and determining the amplitude of the expected Fourier coefficient based on the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of the non-specified frequency of the effective frequency component set; repeatedly performing the following steps : Determine the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, discretely inverse Fourier transform the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, discretely inverse Fourier transform the binary sequence to obtain an actual Fourier coefficient, replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient; until a preset number of iterations are made, output the optimized binary sequence, determine the excitation signal for online testing of the electrochemical impedance spectrum of the new energy battery according to the optimized binary sequence, and determine the electrochemical impedance spectrum according to the excitation signal for online testing of the electrochemical impedance spectrum of the new energy battery.

[0140] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented by a processor to execute the above-mentioned methods for generating an excitation signal for online testing of electrochemical impedance spectroscopy of new energy batteries, the method comprising: determining an expected amplitude of a specified frequency of an effective frequency component set according to a voltage noise component and a priori impedance, determining an amplitude of an expected Fourier coefficient according to the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set; repeatedly performing the following steps: determining an expected amplitude of a Fourier coefficient according to the amplitude of the expected Fourier coefficient; and the current phase angle to determine the expected Fourier coefficient, discrete Fourier inverse transform the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, discrete Fourier inverse transform the binary sequence to obtain an actual Fourier coefficient, replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient; until a preset number of iterations are performed, an optimized binary sequence is output, and an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is determined according to the optimized binary sequence, so as to determine the electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

[0141] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0142] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0143] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery, characterized in that: include: Determine an expected amplitude of a specified frequency of the effective frequency component set according to the voltage noise component and the priori impedance, and determine an amplitude of an expected Fourier coefficient according to the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set; Repeat the following steps: Determine the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, perform an inverse discrete Fourier transform on the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, perform an inverse discrete Fourier transform on the binary sequence to obtain an actual Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient; Until a preset number of iterations are performed, an optimized binary sequence is output, and an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery is determined according to the optimized binary sequence, so as to determine an electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

2. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 1, characterized in that: Before determining the expected amplitude of the specified frequency of the effective frequency component set according to the voltage noise component and the a priori impedance, the method further includes: Based on the typical amplitude-frequency response of new energy batteries, determine the distribution and number of specified harmonics of the defined effective frequency component set at a preset impedance resolution; Determining the a priori impedance based on the low-frequency resistance measurement value, the high-frequency resistance measurement value, and a linear relationship between the low-frequency resistance measurement value and the high-frequency resistance measurement value; The voltage noise component is determined according to low-frequency noise, band-limited white noise, and spectrum peak narrowband noise.

3. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 1, characterized in that: The step of determining the expected amplitude of the specified frequency of the effective frequency component set according to the voltage noise component and the priori impedance includes: ； in, specifies the expected amplitude of the frequencies for the set of valid frequency components, is the a priori impedance, is the voltage noise component, is the normalization term.

4. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 1, characterized in that: After replacing the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient, the method further includes: Initialize the optimal power allocation adaptability to positive infinity, set the first convergence threshold, the second convergence threshold, and the first-order difference step size of the indicator, and repeat the following steps: Calculating the effective power ratio, and when the effective power ratio at the first-order difference step size is less than the first convergence threshold, calculating the current power allocation adaptability; When the current power allocation adaptability is less than the previous power allocation adaptability, updating the optimal power allocation adaptability and the current binary sequence; Until the optimal power allocation adaptability is less than the second convergence threshold, the current phase angle is randomly updated.

5. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 4, characterized in that: After calculating the effective power ratio, the method further includes: When the effective power ratio under the first-order difference step is greater than or equal to the first convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

6. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 4, characterized in that: After calculating the current power allocation adaptability, the method further includes: When the current power allocation adaptability is greater than or equal to the previous power allocation adaptability, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

7. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 4, characterized in that: After updating the optimal power allocation adaptability and the current binary sequence, the method further includes: When the optimal power allocation adaptability is greater than or equal to the second convergence threshold, the expected Fourier coefficient is determined again based on the amplitude of the expected Fourier coefficient and the current phase angle, so as to obtain the actual Fourier coefficient based on the expected Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient.

8. The method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to claim 1, characterized in that: The output optimized binary sequence includes: ； in, For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the specified frequency of the effective frequency component set. For the frequency The value that gradually approaches 0 is used to describe the difference between the frequency domain form of the optimized binary sequence and the expected amplitude of the non-specified frequency of the effective frequency component set. is the actual signal component amplitude of the frequency specified by the effective frequency component set EFCS, k is the harmonic order of the signal at a fixed frequency resolution, and e is a natural constant. is the imaginary unit, Specifies the phase of the frequency for the effective frequency component set EFCS.

9. An excitation signal generating device for online testing of electrochemical impedance spectroscopy of new energy batteries, characterized in that: include: a determining unit, the determining unit being configured to determine an expected amplitude of a specified frequency of the effective frequency component set based on the voltage noise component and the priori impedance, and to determine an amplitude of an expected Fourier coefficient based on the expected amplitude of the specified frequency of the effective frequency component set and the expected amplitude of a non-specified frequency of the effective frequency component set; A repeating unit, wherein the repeating unit is used to repeatedly perform the following steps: Determine the expected Fourier coefficient according to the amplitude of the expected Fourier coefficient and the current phase angle, perform inverse discrete Fourier transform on the expected Fourier coefficient to obtain a time domain signal, binarize the time domain signal to obtain a binary sequence, perform inverse discrete Fourier transform on the binary sequence to obtain an actual Fourier coefficient, and replace the current phase angle of the expected Fourier coefficient with the actual phase angle of the actual Fourier coefficient, until a preset number of iterations are performed; An output unit is used to output an optimized binary sequence, determine an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery according to the optimized binary sequence, and determine an electrochemical impedance spectrum according to the excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for generating an excitation signal for online testing of electrochemical impedance spectroscopy of a new energy battery as described in any one of claims 1 to 8 is implemented.

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