Electrochemical impedance measurement circuit, measurement method, and chip

Abstract

Embodiments of the present application provide an electrochemical impedance measurement circuit, a measurement method, and a chip. The electrochemical impedance measurement circuit comprises: a signal generation module, the signal generation module being used for generating an excitation signal having a preset bandwidth, and the excitation signal being used for exciting an impedance module to output a response signal; and a measurement module, the measurement module being used for determining the electrochemical impedance spectrum of the impedance module in the preset bandwidth on the basis of the excitation signal and response signal. On the basis of corresponding signals of the excitation signal in multiple set sub-bandwidths and a corresponding signal of the response signal in each set sub-bandwidth, the measurement module can determine the impedance of the impedance module at a center frequency corresponding to each set sub-bandwidth. The present application can achieve the purpose of using the measurement module to quickly determine the electrochemical impedance spectrum of the impedance module in the preset bandwidth by means of the excitation signal and the response signal.

Description

Electrochemical impedance measurement circuit, measurement method and chip

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on February 27, 2024, with application number 202410215997.6 and invention name “Electrochemical impedance measurement circuit, measurement method and chip”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of detection technology, and in particular to an electrochemical impedance measurement circuit, a measurement method, and a chip. Background Art

[0003] At present, electrochemical impedance spectroscopy is widely used in the analysis of positive and negative electrode materials of lithium-ion batteries, research on lithium-ion deintercalation and insertion dynamic parameters, solid electrolytes, interfacial reactions, etc., and is a powerful tool for analyzing the performance of lithium-ion batteries. In related technologies, electrochemical impedance spectroscopy measurement methods mainly include frequency response analysis (FRA). The frequency response analysis method generates AC excitation signals of different frequencies, then measures the response signals of the object under test under the excitation signals of different frequencies, and then calculates the impedance of the object under test at the corresponding frequency. However, this method requires multiple outputs of AC excitation signals of different frequencies, and then the object under test outputs response signals of different frequencies. The measurement process can only measure the impedance of the object under test at one frequency at a time, which leads to the problem of long measurement time. Technical Solutions

[0004] In view of the above problems, the embodiments of the present application provide an electrochemical impedance measurement circuit, a measurement method and a chip to solve the above technical problems.

[0005] In a first aspect, an embodiment of the present application provides an electrochemical impedance measurement circuit, which is used to measure the electrochemical impedance spectrum of an impedance module, including: a signal generating module, which is used to generate an excitation signal with a preset bandwidth, the excitation signal is used to excite the impedance module to output a response signal, and the integrated energy of the excitation signal in the preset bandwidth and the integrated bandwidth satisfy a first preset relationship; a measuring module, which is used to determine the electrochemical impedance spectrum of the impedance module within the preset bandwidth based on the excitation signal and the response signal; wherein the measuring module determines the impedance of the impedance module at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal in multiple set sub-bandwidths and the signals of the response signal in multiple set sub-bandwidths, and the frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

[0006] In a second aspect, the present application provides an electrochemical impedance spectroscopy measurement method, comprising: inputting an excitation signal with a preset bandwidth into an impedance module, the integrated energy of the excitation signal in the preset bandwidth and the integrated bandwidth satisfying a first preset relationship, and the preset bandwidth includes multiple set sub-bandwidths; receiving a response signal output by the impedance module in response to the excitation signal; determining the electrochemical impedance spectrum of the impedance module within the preset bandwidth based on the excitation signal and the response signal; wherein, the step of determining the electrochemical impedance spectrum of the impedance module within the preset bandwidth based on the excitation signal and the response signal includes: determining the impedance of the impedance module at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal in multiple set sub-bandwidths and the signals of the response signal in multiple set sub-bandwidths, and the frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

[0007] In a third aspect, the present application provides a chip comprising the electrochemical impedance measurement circuit as described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0009] FIG1 shows a schematic diagram of a module for measuring electrochemical impedance spectroscopy using a fast Fourier transform method in related art.

[0010] FIG2 shows a schematic diagram of a module for measuring electrochemical impedance spectroscopy using a frequency response analysis method in related art.

[0011] FIG3 shows a module schematic diagram of an electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0012] FIG4 shows a schematic diagram of a spectrum of an excitation signal and a response signal within an integration bandwidth range provided by an embodiment of the present application.

[0013] FIG5 shows a schematic diagram of a spectrum of an excitation signal and a response signal within a preset bandwidth range provided by an embodiment of the present application.

[0014] FIG6 shows another schematic diagram of the spectrum of the excitation signal and the response signal within a preset bandwidth range provided by an embodiment of the present application.

[0015] FIG7 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0016] FIG8 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0017] FIG9 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0018] FIG10 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0019] FIG11 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0020] FIG12 shows another module schematic diagram of the electrochemical impedance measurement circuit provided in an embodiment of the present application.

[0021] FIG13 shows a schematic flow chart of an electrochemical impedance spectroscopy measurement method provided in an embodiment of the present application.

[0022] Among them, 1 is an impedance module, 100 is an electrochemical impedance measurement circuit, 10 is a signal generation module, 20 is a measurement module, 21 is a frequency selection module, 22 is an amplitude measurement module, 23 is a signal conversion module, an excitation signal ES, and a response signal RS.

[0023] Implementation Methods of the Application

[0024] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0025] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0026] In the embodiments of the present application, it should be noted that, in this document, relational terms such as first and second, etc., are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0027] Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0028] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0029] In addition, in the embodiments of the present application, "plurality" refers to two or more. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two, or more. For example, "including at least one" means including one, two, or more, and does not limit which ones are included. For example, "including at least one of A, B, and C" means including A, B, C, A and B, A and C, B and C, or A, B, and C.

[0030] It should be noted that in the embodiments of the present application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects are in an "or" relationship.

[0031] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0032] At present, electrochemical impedance spectroscopy measurement methods mainly include the fast Fourier transform method (FFT) and the frequency response analysis method (FRA). Referring to Figure 1, Figure 1 shows a module schematic diagram of the fast Fourier transform method for measuring electrochemical impedance spectroscopy in the related art. The fast Fourier transform method generates an excitation signal through the broadband signal generation module and passes it through the object under test. The response signal output by the object under test and the excitation signal are measured by the analog-to-digital converter. Then, the excitation signal and response signal are converted from time domain signals to frequency domain signals through a fast Fourier transform in the digital system. Finally, the voltage and current signals of the object under test in the frequency domain are obtained, thereby calculating the impedance information of the object under test in the frequency domain, that is, the electrochemical impedance spectrum of the object under test.

[0033] Continuing to refer to FIG2 , FIG2 shows a module schematic diagram of a frequency response analysis method for measuring electrochemical impedance spectroscopy in the related art. The frequency response analysis method generates AC excitation signals of different frequencies through a sinusoidal signal generator, and then measures the integral signal of the response signal output by the object under test under the excitation signals of different frequencies in the time domain through an analog-to-digital converter, and finally obtains the real part and imaginary part of the impedance complex plane of the object under test at the corresponding frequency.

[0034] However, the fast Fourier transform method requires complex digital circuits, while the frequency response analysis method requires multiple outputs of AC excitation signals of different frequencies, and then the object under test outputs response signals of different frequencies. The measurement process can only measure the impedance of the object under test at one frequency at a time, which leads to the problem of long measurement time.

[0035] To this end, the present application provides an electrochemical impedance measurement circuit, a measurement method, and a chip, which are described in detail below.

[0036] First, referring to FIG3 , FIG3 shows a schematic diagram of a module of an electrochemical impedance measurement circuit 100 in an embodiment of the present application. The electrochemical impedance measurement circuit 100 is used to measure the electrochemical impedance spectrum of the impedance module 1, wherein the electrochemical impedance measurement circuit 100 includes:

[0037] a signal generating module 10 configured to generate an excitation signal ES having a preset bandwidth, wherein the excitation signal ES is configured to excite the impedance module 1 to output a response signal RS, wherein the integrated energy of the excitation signal ES in the preset bandwidth satisfies a first preset relationship with the integrated bandwidth;

[0038] The measurement module 20 is used to determine the electrochemical impedance spectrum of the impedance module 1 within a preset bandwidth according to the excitation signal ES and the response signal RS;

[0039] The measurement module 20 determines the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal ES in the multiple set sub-bandwidths and the signals of the response signal RS in the multiple set sub-bandwidths. The frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

[0040] Specifically, the impedance module 1 refers to any module that has an obstructive effect on the alternating current passing therethrough. In some embodiments of the present application, the impedance module 1 may include electronic components, such as resistors, capacitors, inductors, or transistors, such as MOS tubes, triodes, IGBT tubes, or diodes, so as to analyze the electrochemical impedance spectrum of the electronic components through the electrochemical impedance measurement circuit 100. In some embodiments of the present application, the impedance module 1 may include a battery or a component of a battery, such as a carbon-zinc battery, an alkaline battery, a lithium battery, a lead-acid battery, or a nickel-metal hydride battery, and a component of a battery such as an electrode or an electrolyte (electrolyte), so as to analyze the electrochemical impedance spectrum of the battery and its components through the electrochemical impedance measurement circuit 100.

[0041] The signal generating module 10 can generate an excitation signal ES with a preset bandwidth (e.g., 0.1 Hz-10 kHz) so that the excitation signal ES excites the impedance module 1 to output a response signal RS. In some embodiments of the present application, the excitation signal ES can be a voltage signal, and the impedance module 1 outputs a current signal as the response signal RS under the action of the excitation signal ES. In some embodiments of the present application, the excitation signal ES can be a current signal, and the impedance module 1 outputs a voltage signal as the response signal RS under the action of the excitation signal ES.

[0042] In some embodiments of the present application, the signal generation module 10 may output the excitation signal ES through signal simulation. For example, after determining the voltage value of the excitation signal ES in the time domain, the digital-to-analog converter may output the analog voltage in a time sequence, thereby achieving the purpose of simulating the output of the excitation signal ES. In some embodiments of the present application, the signal generation module 10 may simulate the output of the excitation signal ES through an oscillator, and generate the excitation signal ES with a preset bandwidth by controlling the oscillation frequency of the oscillator.

[0043] In some embodiments of the present application, the excitation signal ES and the response signal RS may have a certain phase difference. For example, due to the influence of parasitic capacitance or parasitic inductance in the impedance module 1, after the excitation signal ES excites the impedance module 1, the response signal RS will have a certain phase shift relative to the excitation signal ES. It is understandable that the phase difference between the excitation signal ES and the response signal RS may also be zero.

[0044] The measurement module 20 can determine the electrochemical impedance spectrum of the impedance module 1 within a preset bandwidth based on the excitation signal ES and the response signal RS. In some embodiments of the present application, the measurement module 20 can measure the voltage value / current value of the excitation signal ES and the response signal RS within a certain set sub-bandwidth in the preset bandwidth, and after determining the impedance of the impedance module 1 at the center frequency corresponding to the set sub-bandwidth, measure the voltage value / current value of the excitation signal ES and the response signal RS within another set sub-bandwidth in the preset bandwidth, thereby determining the impedance of the impedance module 1 at the center frequency corresponding to the other set sub-bandwidth, and so on to obtain the impedance at each center frequency within the preset bandwidth. In some embodiments of the present application, the measurement module 20 can measure the voltage value / current value of the excitation signal ES and the response signal RS within the preset bandwidth at one time, and then determine the impedance at the center frequency corresponding to each set sub-bandwidth according to the divided set sub-bandwidth.

[0045] In an embodiment of the present application, the integrated energy of the excitation signal ES in the preset bandwidth and the integrated bandwidth satisfy a first preset relationship. Since the response signal RS has similar characteristics to the excitation signal ES, the integrated energy of the response signal RS in the preset bandwidth and the integrated bandwidth satisfy a second preset relationship. In some embodiments of the present application, the first preset relationship and the second preset relationship may refer to a first-order linear relationship or a high-order relationship. For example, referring to FIG4 , FIG4 shows a spectrum diagram of the excitation signal ES and the response signal RS within the integral bandwidth range in an embodiment of the present application, wherein fx is the upper frequency limit of the integral bandwidth, and fy is the lower frequency limit of the integral bandwidth. The integrated energy of the excitation signal and the response signal RS in the preset bandwidth and the integrated center frequency may satisfy the following relationship: E1(fx-fy)=(fx-fy)*k01*E1(fn) E2(fx-fy)=(fx-fy)*k02*E2(fn)

[0046] Wherein, fx-fy is the integration bandwidth, E1(fx-fy) is the integrated energy of the excitation signal ES corresponding to the integration bandwidth, E2(fx-fy) is the integrated energy of the response signal RS corresponding to the integration bandwidth, E1(fn) is the energy density of the excitation signal ES at the center frequency fn within the integration bandwidth, E2(fn) is the energy density of the response signal RS at the center frequency fn within the integration bandwidth, k01 is the first-order coefficient, and k02 is the first-order coefficient.

[0047] For another example, the integrated energy of the excitation signal and the response signal RS in the preset bandwidth and the integrated center frequency can satisfy the following relationship: E1(fx-fy)=(fx-fy)2*k03*E1(fn) E2(fx-fy)=(fx-fy)2*k04*E2(fn)

[0048] Among them, k03 is the second-order coefficient and k04 is the second-order coefficient.

[0049] Therefore, according to the correspondence between signal energy and amplitude, the amplitude of the excitation signal ES at a certain center frequency can be obtained by converting the amplitude of the excitation signal in a set sub-bandwidth including the frequency. Similarly, the amplitude of the response signal RS at a certain center frequency can be obtained by converting the amplitude of the response signal in a set sub-bandwidth including the frequency. Therefore, the impedance of the impedance module 1 at the center frequency can be calculated by the amplitudes converted from the excitation signal ES and the response signal RS at the same center frequency. Finally, the measurement module 20 can determine the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal ES and the response signal RS in each set sub-bandwidth.

[0050] For example, taking the first preset relationship and the second preset relationship as a first-order linear relationship as an example, according to the corresponding relationship between signal energy and effective amplitude, it can be known that the effective amplitude of the excitation signal ES in the integral bandwidth and the effective amplitude of the excitation signal ES at the center frequency (fn), the effective amplitude of the response signal RS in the integral bandwidth and the effective amplitude of the response signal RS at the center frequency (fn) satisfy the following relationship:

[0051] Wherein, V1(fx-fy) is the effective amplitude of the excitation signal ES in the integration bandwidth, V1(fn) is the effective amplitude of the excitation signal ES at the center frequency (fn), V2(fx-fy) is the effective amplitude of the response signal RS in the integration bandwidth, and V2(fn) is the effective amplitude of the response signal RS at the center frequency (fn).

[0052] Therefore, the effective amplitude of the excitation signal ES at the center frequency (fn) and the effective amplitude of the response signal RS at the center frequency (fn) can be calculated according to the following relationship:

[0053] Assume that the excitation signal ES is a voltage signal, the response signal RS is a current signal, and there is no phase difference between the excitation signal ES and the response signal RS. The impedance Z(fn) of the impedance module 1 at the center frequency (fn) corresponding to the integration bandwidth can be calculated using the following formula:

[0054] After the effective amplitude values ​​of the bandwidth range are V1(fx-fy) and V2(fx-fy), the impedance of the impedance module 1 at the center frequency (fn) corresponding to the integration bandwidth can be calculated according to the above formula.

[0055] In an embodiment of the present application, refer to Figure 5, which shows a schematic diagram of the spectrum of the excitation signal ES and the response signal RS within a preset bandwidth range in an embodiment of the present application, wherein the frequency range of each set sub-bandwidth of a plurality of set sub-bandwidths is within the frequency range of the preset bandwidth, and each set sub-bandwidth corresponds to a center frequency (f1, f2, f3...fn). The measurement module 20 can determine the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal ES and the response signal RS in each set sub-bandwidth.

[0056] For example, the frequency range of the preset bandwidth is 10Hz-60Hz, and the multiple set sub-bandwidths can be divided into 11Hz~20Hz, 21Hz~30Hz, 31Hz~40Hz, 41Hz~50Hz, and 51Hz~60Hz, respectively. The multiple center frequencies corresponding to the multiple set sub-bandwidths are 15Hz, 25Hz, 35Hz, 45Hz, and 55Hz, respectively. When measuring the impedance of the impedance module 1 at the center frequency of 35Hz, the measurement module 20 can first measure the amplitude V1 (31Hz-40Hz) of the set sub-bandwidth corresponding to the center frequency of 31Hz~40Hz of the response signal RS, and then combine the amplitude V2 (31Hz-40Hz) of the set sub-bandwidth corresponding to the center frequency of 31Hz~40Hz of the excitation signal ES to finally calculate the impedance of the impedance module 1 at the center frequency of 35Hz; the impedance measurement process of other center frequencies is the same as above and will not be repeated here.

[0057] It should be noted that the frequency ranges of the various set sub-bandwidths in Figure 5 are evenly divided and do not overlap, which is only an exemplary embodiment. In fact, referring to Figure 6, Figure 6 shows another spectrum diagram of the excitation signal ES and the response signal RS within the preset bandwidth range in an embodiment of the present application. The frequency ranges of the various set sub-bandwidths may also partially overlap. For example, for the embodiment in which the frequency range of the above-mentioned preset bandwidth is 10HZ-60HZ, multiple set sub-bandwidths may also be divided into 11Hz~20Hz, 15Hz~40Hz, 35Hz~50Hz, and 41Hz~60Hz, respectively.

[0058] It can be seen that compared with the related art, the present application does not need to perform fast Fourier transform on the excitation signal ES and the response signal RS to convert the time domain signal into a frequency signal, so there is no need for a complex digital circuit; at the same time, the present application only needs to input an excitation signal ES with a preset bandwidth to the impedance module 1, and there is no need to output AC excitation signals of different frequencies in multiple times, which is also conducive to shortening the measurement time of the electrochemical impedance spectrum of the impedance module 1.

[0059] In some embodiments of the present application, the excitation signal ES can be a 1 / f noise signal or a white noise signal, which is a signal whose signal energy and signal frequency are independent within a certain bandwidth range. Since the 1 / f noise signal and the white noise signal have the characteristic that the integrated energy within a preset bandwidth satisfies the integrated bandwidth in a linear relationship, the excitation signal ES meets the requirements; at the same time, after the impedance module 1 is excited by the 1 / f noise signal or the white noise signal, the response signal RS output by the impedance module 1 also has the characteristics of the 1 / f noise signal or the white noise signal within a certain bandwidth range, so the response signal RS can also meet the requirements.

[0060] In some embodiments of the present application, refer to Figure 7, which shows another schematic diagram of the electrochemical impedance measurement circuit 100 in an embodiment of the present application, wherein the measurement module 20 may include a frequency selection module 21 and an amplitude measurement module 22. The frequency selection module 21 can output multiple response sub-signals based on the response signal RS, each response sub-signal corresponding to a set sub-bandwidth, and the amplitude measurement module 22 can measure the amplitude of the response sub-signal changing with time, so as to calculate the complex impedance of the impedance module 1 at the center frequency corresponding to the set sub-bandwidth.

[0061] For example, for the effective amplitude of the response signal RS in the above formula corresponding to the set sub-bandwidth

[0062] The amplitude of RS changes with time.

[0063] It should be noted that when the excitation signal ES is output in a time sequence through the digital-to-analog converter, the amplitude V1 (fx-fy) of the excitation signal ES in the corresponding set sub-bandwidth is a known quantity and does not need to be measured; when the excitation signal ES with a preset bandwidth is generated by controlling the oscillation frequency of the oscillator, the amplitude V1 (fx-fy) of the excitation signal ES in the corresponding set sub-bandwidth can be measured in the same way as above, which will not be repeated here.

[0064] Exemplarily, the frequency selection module 21 may include any one or more of a second-order bandpass filter, a resonant bandpass filter, a SAW bandpass filter, a BAW bandpass filter or a microstrip bandpass filter, and the amplitude measurement module 22 may include any one or more of a successive approximation analog-to-digital converter, an integral analog-to-digital converter or a parallel analog-to-digital converter.

[0065] In some embodiments of the present application, refer to Figure 8, which shows another schematic diagram of the electrochemical impedance measurement circuit 100 in an embodiment of the present application, wherein the frequency selection module 21 includes a frequency selector, and the amplitude measurement module 22 includes multiple analog-to-digital converters. The frequency selector is used to output multiple response sub-signals according to the response signal RS, and each analog-to-digital converter measures the amplitude of at least one response sub-signal changing with time.

[0066] For example, the frequency selector can output a response sub-signal with a set sub-bandwidth of 11 Hz-20 Hz, a response sub-signal with a set sub-bandwidth of 21 Hz-30 Hz, and a response sub-signal with a set sub-bandwidth of 31 Hz-40 Hz, respectively. One analog-to-digital converter measures the amplitude of the response sub-signal of 11 Hz-20 Hz that changes with time, another analog-to-digital converter measures the amplitude of the response sub-signal of 21 Hz-30 Hz that changes with time, and another analog-to-digital converter measures the amplitude of the response sub-signal of 31 Hz-40 Hz that changes with time. In other words, the amplitude measurements of the response sub-signals corresponding to different set sub-bandwidths are performed simultaneously, so the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth can be calculated simultaneously.

[0067] In some other embodiments of the present application, refer to Figure 9, which shows another schematic diagram of the electrochemical impedance measurement circuit 100 in an embodiment of the present application, wherein the frequency selection module 21 includes multiple bandpass filters, and the amplitude measurement module 22 includes multiple analog-to-digital converters; the bandpass filters correspond one-to-one to the analog-to-digital converters, each bandpass filter is used to output a response sub-signal corresponding to a set sub-bandwidth, and each analog-to-digital converter is used to measure the amplitude of the corresponding response sub-signal changing over time.

[0068] Specifically, each bandpass filter can filter out the part of the response signal RS at other frequencies and only pass the part corresponding to the set sub-bandwidth, so that the analog-to-digital converter can measure the amplitude of the response signal RS in the corresponding set sub-bandwidth. Finally, multiple groups of bandpass filters and analog-to-digital converters are used to simultaneously measure the amplitude of the response signal RS in each set sub-bandwidth to shorten the measurement time of the electrochemical impedance spectrum of the impedance module 1. For example, the frequency ranges of the pass signals of the multiple band-pass filters are 11 Hz-15 Hz, 20 Hz-30 Hz, and 35 Hz-40 Hz, respectively. That is, the multiple band-pass filters can respectively output a response sub-signal with a set sub-bandwidth of 11 Hz-15 Hz, a response sub-signal with a set sub-bandwidth of 20 Hz-30 Hz, and a response sub-signal with a set sub-bandwidth of 35 Hz-40 Hz. One analog-to-digital converter measures the amplitude of the response sub-signal of 11 Hz-15 Hz that changes with time, another analog-to-digital converter measures the amplitude of the response sub-signal of 20 Hz-30 Hz that changes with time, and another analog-to-digital converter measures the amplitude of the response sub-signal of 35 Hz-40 Hz that changes with time. Similarly, the amplitude measurements of the response sub-signals corresponding to different set sub-bandwidths are performed simultaneously, so the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth can be calculated simultaneously.

[0069] In some embodiments of the present application, referring to FIG. 10 , which shows another schematic diagram of an electrochemical impedance measurement circuit 100 according to an embodiment of the present application, the measurement module 20 further includes a signal conversion module 23 , which is configured to convert the response signal RS into a voltage signal or a current signal. For example, in an embodiment where the response signal RS is a voltage signal, the signal conversion module 23 may convert the response signal RS into a current signal; in another embodiment where the response signal RS is a current signal, the signal conversion module 23 may convert the response signal RS into a voltage signal.

[0070] As an example, referring to FIG11 , FIG11 shows another schematic diagram of an electrochemical impedance measurement circuit 100 in an embodiment of the present application. The signal conversion module includes a resistor R0 and an operational amplifier OP. One end of the resistor R0 is connected to the inverting input terminal of the operational amplifier OP, and the other end is connected to the output terminal of the operational amplifier OP. The non-inverting input terminal of the operational amplifier OP is used to receive the response signal RS. The inverting amplifier composed of the resistor R0 and the operational amplifier OP not only converts the response signal RS into a voltage signal, but also amplifies the response signal RS to reduce the measurement error of the response signal RS by the analog-to-digital converter (e.g., a successive approximation analog-to-digital converter).

[0071] It is understandable that the signal conversion module 23 is not limited to the above embodiment, and the response signal RS may also pass through a resistor, which will generate a corresponding voltage drop and can be used as the output of the converted voltage signal.

[0072] As an exemplary application embodiment, referring to Figure 12, Figure 12 shows another schematic diagram of the electrochemical impedance measurement circuit 100 in an embodiment of the present application, wherein the impedance module 1 includes a battery cell, a first operational amplifier OP1, a second operational amplifier OP2, a first resistor R1 and a second resistor R2. The battery cell is a three-electrode battery having a first electrode, a second electrode and a reference electrode. The inverting input terminal of the first operational amplifier OP1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the signal generating module 10 and receives the excitation signal ES. The output terminal of the first operational amplifier OP1 is connected to the first electrode of the battery cell, so that the first electrode of the battery cell can receive the amplified excitation signal ES.

[0073] The non-inverting input terminal of the second operational amplifier OP2 is connected to the reference electrode of the battery cell, the inverting input terminal and the output terminal of the second operational amplifier OP2 are short-circuited, and the first end of the second resistor R2 is connected to the inverting input terminal of the first operational amplifier. At this time, the second operational amplifier OP2 acts as a voltage follower, so that the reference electrode voltage of the battery cell is equal to the voltage of the non-inverting input terminal of the first operational amplifier OP1, thereby ensuring that the reference electrode of the battery cell is fixed without voltage drop.

[0074] During the electrochemical impedance spectroscopy test process, the signal generating module 10 outputs an excitation signal ES to the battery cell through the first operational amplifier OP1. The battery cell generates a response current under the action of the excitation signal ES. The inverting amplifier amplifies the response current and converts it into a voltage signal. The frequency selection module 21 is then used to filter the voltage signal to obtain a response signal RS corresponding to the sub-set bandwidth. The amplitude measurement module 22 then measures the response signal RS of the sub-set bandwidth in the time domain and calculates the amplitude of the response signal RS at the center frequency of the sub-set bandwidth. Finally, the amplitude and phase difference information of the excitation signal ES and the response signal RS at the center frequency of the sub-set bandwidth are combined to calculate the impedance value of the impedance module 1 at the center frequency.

[0075] In some embodiments of the present application, for example, for an embodiment in which there is a phase difference between the excitation signal ES and the response signal RS, the excitation signal ES includes a first excitation signal ES and a second excitation signal ES; the response signal RS includes a first response signal RS output by the impedance module 1 according to the first excitation signal ES, and a second response signal RS output by the impedance module 1 according to the second excitation signal ES; the phase difference between the first excitation signal ES and the second excitation signal ES is 180°, and the phase difference between the first response signal RS and the second response signal RS is 180°; the measurement module 20 determines the impedance of the impedance module 1 at each center frequency corresponding to the first excitation signal ES, the second excitation signal ES, the first response signal RS, and the second response signal RS in each set sub-bandwidth.

[0076] It should be noted that, since the impedance module 1 generally has capacitive reactance elements or inductive reactance elements such as its own capacitance, its own inductance, parasitic capacitance or parasitic inductance, the response signal RS output by the impedance module 1 when stimulated by the excitation signal ES will undergo a certain phase shift. For the impedance of the impedance module 1 at a certain frequency, it is necessary to simultaneously obtain the real part and the imaginary part of the complex impedance. In the above embodiment, the signal generation module 10 can first output a first excitation signal ES to stimulate the impedance module 1 to output a first response signal RS; then output a second excitation signal ES with a phase difference of 180° from the first excitation signal ES, so that the impedance module 1 outputs a second response signal RS with a phase difference of 180° from the first response signal RS. Finally, the measurement module 20 can use the first excitation signal ES, the second excitation signal ES, the first response signal RS, and the second response signal RS in each set sub-bandwidth to determine the real part and the imaginary part of the impedance of the impedance module 1 at each corresponding center frequency.

[0077] As an example, the first excitation signal ES can be divided into multiple first sub-excitation signals corresponding to multiple set sub-bandwidths, and the first sub-excitation signals correspond to the set sub-bandwidths one-to-one. The second excitation signal ES can be divided into multiple second sub-excitation signals corresponding to multiple set sub-bandwidths, and the second sub-excitation signals correspond to the set sub-bandwidths one-to-one. The first response signal RS can be divided into multiple first sub-response signals corresponding to multiple set sub-bandwidths, and the first sub-response signals correspond to the set sub-bandwidths one-to-one. The second response signal RS can be divided into multiple second sub-response signals corresponding to multiple set sub-bandwidths, and the second sub-response signals correspond to the set sub-bandwidths one-to-one.

[0078] The measurement module 20 can determine the phase difference between the first sub-excitation signal and the first sub-response signal at the corresponding center frequency based on the first sub-response signal and the second sub-response signal corresponding to the same set sub-bandwidth. For example, at a certain center frequency (fn), the corresponding first sub-response signal and the second sub-response signal are

[0079] The amplitudes of the response signal and the second sub-response signal are shown in FIG1 , and θ1 is the phases corresponding to the first sub-response signal and the second sub-response signal.

[0080] Therefore, the phase difference between the first sub-excitation signal and the first sub-response signal at the center frequency (fn) can be calculated according to the following formula:

[0081] Difference.

[0082] According to the complex impedance calculation formula, the measurement module 20 can determine the complex impedance of the impedance module 1 at the center frequency (fn) corresponding to the set sub-bandwidth based on the first sub-excitation signal, the first sub-response signal, and the phase difference corresponding to the same set sub-bandwidth:

[0083] It can be seen that by first using the first excitation signal ES to excite the impedance module 1 to output the first response signal RS, and then using the second excitation signal ES with a phase difference of 180° from the first excitation signal ES, the impedance module 1 is excited to output the second response signal RS with a phase difference of 180° from the first response signal RS. Finally, the measurement module 20 can use the first excitation signal ES, the second excitation signal ES, the first response signal RS and the second response signal RS in each set sub-bandwidth to finally determine the real part and imaginary part of the impedance of the impedance module 1 corresponding to each center frequency.

[0084] Furthermore, in order to better implement the electrochemical impedance measurement circuit 100 in the embodiment of the present application, based on the electrochemical impedance measurement circuit 100, the present application also provides an electrochemical impedance spectroscopy measurement method. Referring to FIG13 , FIG13 shows a flow chart of the electrochemical impedance spectroscopy measurement method in the embodiment of the present application, wherein the electrochemical impedance spectroscopy measurement method includes:

[0085] Step S1301: inputting an excitation signal ES having a preset bandwidth into the impedance module 1, wherein the integrated energy of the excitation signal ES in the preset bandwidth and the integrated bandwidth satisfy a first preset relationship, and the preset bandwidth includes a plurality of set sub-bandwidths;

[0086] Step S1302, receiving a response signal RS output by the impedance module 1 in response to the excitation signal ES;

[0087] Step S1303, determining the electrochemical impedance spectrum of the impedance module 1 within a preset bandwidth according to the excitation signal ES and the response signal RS;

[0088] Among them, the step of determining the electrochemical impedance spectrum of the impedance module 1 within a preset bandwidth based on the excitation signal ES and the response signal RS includes: determining the impedance of the impedance module 1 at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal ES in multiple set sub-bandwidths and the signals of the response signal RS in multiple set sub-bandwidths, and the frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

[0089] More specifically, each set sub-bandwidth corresponds to a center frequency, so that the impedance of the impedance module 1 at each center frequency can be determined based on the excitation signal ES and the response signal RS in each set sub-bandwidth. For example, the frequency range of the preset bandwidth is 10HZ-60HZ, and the multiple set sub-bandwidths can be divided into 11Hz~20Hz, 21Hz~30Hz, 31Hz~40Hz, 41Hz~50Hz, and 51Hz~60Hz, respectively. The multiple center frequencies corresponding to the multiple set sub-bandwidths are 15Hz, 25Hz, 35Hz, 45Hz, and 55Hz, respectively. When measuring the impedance of the impedance module 1 at a center frequency of 35Hz, the measurement module 20 can first measure the amplitude of the response signal RS at the set sub-bandwidth corresponding to the center frequency of 31Hz~40Hz, and then combine it with the amplitude of the excitation signal ES at the set sub-bandwidth corresponding to the center frequency of 31Hz~40Hz to finally calculate the impedance of the impedance module 1 at the center frequency of 35Hz.

[0090] The present application generates an excitation signal ES with a preset bandwidth, and excites the impedance module 1 to output a response signal RS through the excitation signal ES. Since the integrated energy of the excitation signal ES within the preset bandwidth and the integrated bandwidth satisfy a first preset relationship, and the integrated energy of the response signal RS within the preset bandwidth and the integrated bandwidth satisfy a second preset relationship, the amplitude of the excitation signal ES at a certain frequency can be obtained by converting the amplitude of the excitation signal ES in a certain bandwidth range including the frequency. Similarly, the amplitude of the response signal RS at a certain frequency can be obtained by converting the amplitude of the response signal RS in a certain bandwidth range including the frequency. Therefore, the impedance of the impedance module 1 at the frequency can be calculated by the amplitudes converted from the excitation signal ES and the response signal RS at the same frequency, thereby finally achieving the purpose of quickly determining the electrochemical impedance spectrum of the impedance module 1 within the preset bandwidth through the excitation signal ES and the response signal RS.

[0091] The present invention also provides a chip including the electrochemical impedance measurement circuit 100. An integrated circuit (IC) is also referred to as a chip, and the chip may be, but is not limited to, a system on chip (SOC) chip or a system in package (SIP) chip.

[0092] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. An electrochemical impedance measurement circuit for measuring the electrochemical impedance spectrum of an impedance module, characterized in that: include: a signal generating module, the signal generating module being configured to generate an excitation signal having a preset bandwidth, the excitation signal being configured to excite the impedance module to output a response signal, wherein the integrated energy of the excitation signal in the preset bandwidth and the integrated bandwidth satisfy a first preset relationship; a measurement module, configured to determine an electrochemical impedance spectrum of the impedance module within the preset bandwidth based on the excitation signal and the response signal; The measurement module determines the impedance of the impedance module at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal in multiple set sub-bandwidths and the signals of the response signal in multiple set sub-bandwidths, and the frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

2. The electrochemical impedance measurement circuit according to claim 1, wherein: The measurement module includes a frequency selection module and an amplitude measurement module; The frequency selection module is used to output a plurality of response sub-signals according to the response signal, each of the response sub-signals corresponds to a set sub-bandwidth, and the amplitude measurement module is used to measure the amplitude of the response sub-signal that changes with time.

3. The electrochemical impedance measurement circuit according to claim 2, wherein: The frequency selection module includes a frequency selector, and the amplitude measurement module includes a plurality of analog-to-digital converters; The frequency selector is used to output a plurality of the response sub-signals, and each of the analog-to-digital converters measures the amplitude of at least one of the response sub-signals that changes with time.

4. The electrochemical impedance measurement circuit according to claim 2, wherein: The frequency selection module includes a plurality of bandpass filters, and the amplitude measurement module includes a plurality of analog-to-digital converters; The bandpass filters correspond one-to-one to the analog-to-digital converters. Each of the bandpass filters is used to output the response sub-signal corresponding to the set sub-bandwidth, and each of the analog-to-digital converters is used to measure the amplitude of the corresponding response sub-signal that changes with time.

5. The electrochemical impedance measurement circuit according to claim 2, wherein: The measurement module further includes a signal conversion module, and the signal conversion module is used to convert the response signal into a voltage signal or a current signal.

6. The electrochemical impedance measurement circuit according to claim 5, wherein: The signal conversion module includes a resistor and an operational amplifier; One end of the resistor is connected to the inverting input terminal of the operational amplifier, and the other end is connected to the output terminal of the operational amplifier. The non-inverting input terminal of the operational amplifier is used to receive the response signal.

7. The electrochemical impedance measurement circuit according to claim 1, wherein: The excitation signal includes a first excitation signal and a second excitation signal; The response signal includes a first response signal output by the impedance module according to the first excitation signal, and a second response signal output by the impedance module according to the second excitation signal; A phase difference between the first excitation signal and the second excitation signal is 180°, and a phase difference between the first response signal and the second response signal is 180°; The measurement module determines the impedance of the impedance module at each center frequency according to the first excitation signal, the second excitation signal, the first response signal, and the second response signal in each set sub-bandwidth.

8. The electrochemical impedance measurement circuit according to claim 7, wherein: The first excitation signal includes a plurality of first sub-excitation signals corresponding to the plurality of set sub-bandwidths, and the second excitation signal includes a plurality of second sub-excitation signals corresponding to the plurality of set sub-bandwidths; The first response signal includes a plurality of first sub-response signals corresponding to the plurality of set sub-bandwidths, and the second response signal includes a plurality of second sub-response signals corresponding to the plurality of set sub-bandwidths; The measurement module determines, based on the first sub-response signal and the second sub-response signal corresponding to the same set sub-bandwidth, a phase difference between the first sub-excitation signal and the first sub-response signal at a corresponding center frequency; The measurement module determines the complex impedance of the impedance module at the center frequency according to the first sub-excitation signal, the first sub-response signal, and the phase difference corresponding to the same set sub-bandwidth.

9. The electrochemical impedance measurement circuit according to any one of claims 1 to 8, characterized in that: The excitation signal is a 1 / f noise signal or a white noise signal.

10. A method for measuring electrochemical impedance spectroscopy, characterized in that: include: Inputting an excitation signal with a preset bandwidth into the impedance module, wherein the integrated energy and the integrated bandwidth of the excitation signal in the preset bandwidth satisfy a first preset relationship; receiving a response signal output by the impedance module in response to the excitation signal; determining an electrochemical impedance spectrum of the impedance module within the preset bandwidth according to the excitation signal and the response signal; The step of determining the electrochemical impedance spectrum of the impedance module within the preset bandwidth based on the excitation signal and the response signal includes: determining the impedance of the impedance module at the center frequency corresponding to each set sub-bandwidth based on the signals of the excitation signal in multiple set sub-bandwidths and the signals of the response signal in multiple set sub-bandwidths, and the frequency range of each set sub-bandwidth is within the frequency range of the preset bandwidth.

11. A chip, characterized in that: The method comprises the electrochemical impedance measurement circuit according to any one of claims 1 to 9.

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