KR20200143207A - Method of evaluating impedance spectroscopy for used battery module, recording medium and apparatus for performing the method - Google Patents

Abstract

Disclosed are a method for measuring an impedance spectrum of a waste battery module, and a recording medium and a device for performing the same. The device for measuring an impedance spectrum of a waste battery module generates a perturbation signal to apply the signal to a waste battery module, measures a response signal of the waste battery module for the perturbation signal, and uses the response signal to display the impedance spectrum of the waste battery module.

Description

Impedance spectrum measurement method of waste battery module, recording medium and device for performing it {METHOD OF EVALUATING IMPEDANCE SPECTROSCOPY FOR USED BATTERY MODULE, RECORDING MEDIUM AND APPARATUS FOR PERFORMING THE METHOD}

The present invention relates to a method for measuring an impedance spectrum of a waste battery module, a recording medium and an apparatus for performing the same, and more particularly, a method for measuring an impedance spectrum for evaluating the remaining life of a waste battery module, and a recording medium and apparatus for performing the same It is about.

Automobile batteries will be replaced when they reach 80% of their initial capacity, and the number of used batteries is expected to increase explosively. Due to the environmental pollution problem that occurs when the battery for automobiles is disposed of, there is a trend of introducing a producer responsible recycling system that imposes recycling obligations to battery producers at home and abroad, and thus, interest in battery reuse is increasing.

When the vehicle battery module reaches 80% or less of its initial capacity, the driving range is considerably limited, but it has sufficient capacity to be used in an energy storage system (ESS). However, when the vehicle battery module is reused, the overall energy storage system performance may be deteriorated due to an imbalance between the battery modules.

Therefore, in order to recycle the waste battery, an accurate evaluation of the remaining life must be performed, and the development of a device capable of measuring the internal impedance of the battery is very important.

On the other hand, there are already many products and technologies for measuring the impedance of a battery pack, but all of them are for commercial batteries, and it is difficult to find actual products for systems and methods for measuring the impedance of waste batteries.

In addition, as an impedance spectrum measurement method, it is widely used to apply a periodic excitation signal of a certain frequency and measure the spectrum with a phase detection device such as a frequency response analyzer (FRA), but the measurement method as described above is a signal generator and a phase detector. Expensive devices such as, etc. must be used, and at least two cycles of signals are required to remove the effect of transient characteristics, as well as measurements are performed sequentially when spectrums for multiple frequencies are required. There is a problem of lengthening.

An aspect of the present invention provides a method for measuring an impedance spectrum of a waste battery module, shown by measuring an impedance spectrum of a waste battery module using electrochemical impedance spectroscopy (EIS), and a recording medium and apparatus for performing the same do.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above problem, the apparatus for measuring impedance spectrum of a waste battery module of the present invention includes a perturbation induction unit that generates a perturbation signal and applies it to a waste battery module, a sensor unit that measures a response signal of the waste battery module to the perturbation signal, A response signal processor for calculating the impedance of the waste battery module for each frequency of the perturbation signal using the response signal and the impedance spectrum of the waste battery module for each frequency of the perturbation signal in the form of a Nyquist plot It includes an impedance spectrum measuring unit to display.

Meanwhile, the response signal processor may remove noise by leaving only a DC component from the response signal, and calculate the magnitude and phase of the response signal from which the noise is removed to calculate the impedance of the waste battery module.

In addition, the response signal processing unit generates a reference signal divided into an in-phase component having the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal, and multiplying the response signal by the reference signal, respectively, and the response signal The real component and the imaginary component of are calculated, and the response signal from which noise is removed may be calculated by taking an average value of the real component and the imaginary component of the response signal, respectively.

In addition, the sensor unit may include a current measurement unit measuring a response current of the waste battery module using a shunt resistance and a voltage measurement unit measuring a response voltage of the waste battery module using a resistance distribution circuit. have.

In addition, the voltage measuring unit may measure the response voltage by a 4-terminal probe measurement method in which a current is applied to two terminals and a voltage is measured through two terminals.

In addition, the impedance spectrum measuring unit may calculate and display a parameter of an element constituting an equivalent circuit model corresponding to the impedance spectrum.

Meanwhile, in the impedance spectrum measurement method of the waste battery module of the present invention, in the impedance spectrum measurement method in the impedance spectrum measuring apparatus for horizontal evaluation of the residual level of the waste battery module, generating a perturbation signal and applying it to the waste battery module, the perturbation Measuring a response signal of the waste battery module to a signal, calculating an impedance of the waste battery module for each frequency of the perturbation signal using the response signal, and an impedance of the waste battery module for each frequency of the perturbation signal And displaying the spectrum in the form of a Nyquist plot.

On the other hand, calculating the impedance of the waste battery module for each frequency of the perturbation signal using the response signal includes removing noise by leaving only a DC component in the response signal, and the magnitude of the response signal from which noise is removed, and It may include calculating the phase and calculating the impedance of the waste battery module.

In addition, the step of removing noise by leaving only a DC component from the response signal includes generating a reference signal divided into an in-phase component having the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal, and the response signal And calculating the real and imaginary components of the response signal by multiplying each by the reference signal, and calculating the response signal from which noise has been removed by taking average values of the real and imaginary components of the response signal, respectively. have.

In addition, the step of measuring the response signal of the waste battery module to the perturbation signal is a 4-terminal probe measurement method in which current is applied to two terminals and voltage is measured through two terminals, and the response voltage of the waste battery module It may include the step of measuring.

In addition, the step of curve fitting the impedance of the waste battery module for each frequency of the perturbation signal to a Nyquist plot to display the impedance spectrum of the waste battery module includes: an equivalent circuit model corresponding to the impedance spectrum. It may include the step of calculating and displaying the parameters of the constituting element.

In addition, it may be a computer-readable recording medium in which a computer program is recorded for performing the method of measuring the impedance spectrum of the waste battery module.

According to the present invention, high accuracy of measurement of the impedance spectrum of the waste battery module can be ensured, and when the remaining life of the waste battery module calculated using this is reflected in grading for the configuration of the energy storage device, the You will be able to guarantee the overall system performance.

1 is a diagram schematically illustrating an operation of an apparatus for measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.
2 is a diagram showing a Nyquist Plot.
3 is an example of an equivalent circuit model corresponding to the Nyquist plot shown in FIG. 2.
4 is a control block diagram of an apparatus for measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.
5 is a detailed block diagram of the sensor unit shown in FIG. 4.
6 is an example of a screen output from the impedance spectrum measuring unit shown in FIG. 4.
7 is a flowchart of a method of measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.
8 is a diagram showing an impedance spectrum measured using an apparatus for measuring an impedance spectrum of a waste battery module and commercial equipment according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The detailed description of the present invention to be described later refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. It is to be understood that the various embodiments of the present invention are different from each other, but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in relation to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description to be described below is not intended to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all scopes equivalent to those claimed by the claims. Like reference numerals in the drawings refer to the same or similar functions over several aspects.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a diagram schematically illustrating an operation of an apparatus for measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.

Referring to FIG. 1, an impedance spectrum measuring apparatus (hereinafter, impedance spectrum measuring apparatus) 1 of a waste battery module according to an embodiment of the present invention may measure and output an impedance spectrum of a waste battery module 2. .

In this embodiment, the waste battery module 2 is a vehicle battery and is defined as a battery module having a capacity of 80% or less compared to the initial capacity. The waste battery module 2 must be disposed of by limiting the driving range of the electric vehicle, and is reused as an energy storage system (ESS) in order to prevent environmental destruction due to disposal. When configuring the energy storage device with the waste battery module 2, it is important to select the waste battery module 2 having a similar remaining life. This is because the performance imbalance between the waste battery modules 2 degrades the performance of the entire system.

The impedance spectrum measuring device 1 according to an embodiment of the present invention can measure the impedance spectrum of the waste battery module 2, and the impedance spectrum measuring device 1 is a battery cell and an electrochemical device such as a super capacitor. Impedance spectrum can also be measured.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention measures the impedance of the waste battery module 2 and calculates a parameter according thereto, and compares the parameter with the parameter of the new battery module to the residual of the waste battery module 2 Life expectancy can be predicted. The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention reflects the remaining life of the waste battery module 2 in grading for the configuration of the energy storage device to ensure the overall system performance of the energy storage device. I will be able to.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention is an electrochemical impedance spectroscopy apparatus (EIS Instrument) for measuring the internal impedance of the waste battery module 2 by electrochemical impedance spectroscopy (EIS). can do.

Electrochemical Impedance Spectroscopy (EIS) is a non-destructive test method that induces small perturbation on the object to be measured, measures the AC impedance spectrum from the response to the induced perturbation, and uses the measured AC impedance into an impedance model that can be physically explained. It is a technology that estimates the aging or performance state of the battery by extracting the parameters of the battery through curve-fitting. This electrochemical impedance spectroscopy (EIS) is based on the fact that impedances related to different processes have different time constants, and to ensure the validity of the measurement, linearity, causality, and stability. And it must satisfy the four conditions of finite.

Hereinafter, an impedance spectrum measurement step of the waste battery module 2 based on electrochemical impedance spectroscopy (EIS) in the impedance spectrum measurement apparatus 1 according to an embodiment of the present invention will be briefly described.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may generate a perturbation signal and apply it to the waste battery module 2.

For example, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may generate a perturbation voltage of a sinusoidal waveform through a frequency change using software composed of NI's DAQ board and LabVIEW. In addition, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may convert a perturbation voltage into a perturbation current I _AC using Power OP-Amp and apply it to the waste battery module 2.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may measure a response signal of the waste battery module 2 to the perturbation signal. To this end, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention includes a sensing circuit for measuring a voltage response signal (V _AC ) and a current response signal (I _AC ) of the waste battery module 2, respectively. I can.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may measure the impedance spectrum of the waste battery module 2 by using the response signal of the waste battery module 2.

For example, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may apply voltage and current response signals of the waste battery module 2 to a DAQ board to convert them into digital data. The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may measure the impedance spectrum from the voltage and current response signals of the waste battery module 2 using software composed of LabVIEW. In this regard, a detailed description will be provided later.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may curve-fit the impedance spectrum of the waste battery module 2 to an impedance model.

For example, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may curve-fit the impedance spectrum of the waste battery module 2 using an impedance equivalent circuit model.

The impedance spectrum of a widely used lithium-ion battery can be represented by a Nyquist plot. This will be described with reference to FIGS. 2 and 3.

FIG. 2 is a diagram illustrating a Nyquist plot, and FIG. 3 is an example of an equivalent circuit model corresponding to the Nyquist plot shown in FIG. 2.

Referring to FIG. 2, the Nyquist plot may represent the shape of two semicircles (SEI and charge transfer) and a diverging straight line (Diffusion).

3 is a type of electrical model required for curve fitting to a Nyquist plot, and corresponds to an Adapted Randles ECM (AR-ECM).

3, in the Adapted Randles ECM (AR-ECM), the inductance (L) represents the porosity of the electrode at high frequency and the component due to the lead wire connected to the battery, and the ohmic resistance (R _s ) represents the electrolyte resistance, contact resistance, and electron Indicates contact, etc.

In addition, in the Adapted Randled ECM (AR-ECM), the resistance component (R _SEI ) and the double layer (CPE _SEI ) are represented by the first semicircle in FIG. 2, and are formed in the solid electrolyte interface (SEI). It represents the film resistance corresponding to charge transfer.

In addition, in the Adapted Randled ECM (AR-ECM), the resistance component (R _ct ) and the double layer (CPE _dl ) are represented by the second semicircle in FIG. 2, and charge transfer resistance representing the oxidation and reduction reactions of lithium ions at the electrode material interface. Components and bilayers are shown.

The double layer (CPE) shown in FIG. 3 represents the porosity and torsion characteristics of an electrode, and can be expressed as Equation 1 below.

In Equation 1, Q means a time constant, and n is a real number between 0 and 1. The double layer (CPE) is a pure resistance when N=0 and acts like a pure capacitor when n=1.

In addition, in the Adapted Randled ECM (AR-ECM), the Warburg impedance (Z _W ) is represented by the linear shape of FIG. 2, and is used to model the diffusion process of lithium ions in a solid state, and can be expressed as Equation 2 below. .

In Equation 2, R _W denotes a Warburg resistance, and as shown in FIG. 2, it can be understood that it appears as a straight line with a 45 degree angle in a low frequency region.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may generate a Nyquist plot of the waste battery module 2 and output it in real time, and the waste battery module 2 according to the Nyquist plot Each parameter can be calculated and provided.

In addition, the impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may be used to predict the remaining life of the waste battery module 2, and grading a plurality of waste battery modules 2 according to the remaining life Can provide.

4 is a control block diagram of an apparatus for measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.

Referring to FIG. 4, an impedance spectrum measuring apparatus 1 according to an embodiment of the present invention includes a perturbation inducing part 10, a sensor part 30, a response signal processing part 50, and an impedance spectrum measuring part 70. can do.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention may be implemented by more components than the components shown in FIG. 4 or by fewer components.

The impedance spectrum measuring apparatus 1 according to an embodiment of the present invention is a device capable of input and output of information, and may be executed by installing software (application) for measuring an impedance spectrum, and the perturbation inducing unit 10 shown in FIG. 4 , The sensor unit 30, the response signal processing unit 50, and the impedance spectrum measurement unit 70 may be controlled by software executed in the device 1 according to an embodiment of the present invention.

The impedance spectrum measuring apparatus 1 according to an exemplary embodiment of the present invention may measure the impedance spectrum of the waste battery module 2 by electrochemical impedance spectroscopy (EIS), as shown in FIG. 1.

Hereinafter, each component of the apparatus 1 for measuring an impedance spectrum according to an embodiment of the present invention shown in FIG. 4 will be described in detail.

The perturbation inducing unit 10 may generate a perturbation signal and apply it to the waste battery module 2.

For example, the perturbation inducing unit 10 may generate a perturbation voltage of a sinusoidal waveform through a frequency change using software composed of NI's DAQ board and LabVIEW. In addition, the perturbation induction unit 10 may convert the perturbation voltage into perturbation current I _AC using Power OP-Amp and apply it to the waste battery module 2.

Here, the size of the perturbation current (IAC) converted through the Power OP-Amp may vary according to the ratio of the product of the input resistance and the sensing resistance to the product of the perturbation voltage and the feedback resistance, and at this time, the size of the sensing resistor is It may appear smaller than the size of at least one of the feedback resistance and the input resistance.

In this regard, one side of the input resistance may be connected to the inverting input terminal and the non-inverting input terminal of the Power OP-Amp, respectively, the perturbation voltage is input from the other side of the input resistance connected to the non-inverting input terminal, and the inverting input terminal The other side of the input resistor connected to may be grounded.

In addition, one side of the feedback resistor may be connected to each of the inverting input terminal and the non-inverting input terminal, and accordingly, it can be understood that the input resistance and the feedback resistance of the inverting input terminal and the non-inverting input terminal are connected at each contact point.

In this case, it can be understood that the input resistance and feedback resistance connected to the inverting input terminal and one contact point are different from the input resistance and feedback resistance connected to the non-inverting input terminal and one contact point.

Meanwhile, the non-inverting input terminal and the other side of the feedback resistor connected to one side of the input resistance are connected to the sensing resistor, and the other side of the sensing resistor is the inverting input terminal and the other side of the feedback resistor connected to the input resistance and the power It can be connected at the contact point of the output terminal of the OP-Amp.

Accordingly, it can be understood that the perturbation current (IAC) is a current flowing through the sensing resistor, and the waste battery module 2 is connected to the contact point of the non-inverting input terminal and the sensing resistor, so that the perturbation current (IAC) is applied. I can.

The sensor unit 30 may measure a response signal of the waste battery module 2 to the perturbation signal.

The response signal can be divided into response current and response voltage.

The sensor unit 30 may measure the response current and the response voltage, respectively, and transmit them to the response signal processing unit 50 to be described later. This will be described with reference to FIG. 5.

5 is a detailed block diagram of the sensor unit shown in FIG. 4.

Referring to FIG. 5, the sensor unit 30 may include a current measurement unit 31 and a voltage measurement unit 33.

The current measuring unit 31 may measure the response current of the waste battery module 2.

For example, the current measuring unit 31 may measure the response current of the waste battery module 2 including a shunt resistance.

The voltage measurement unit 33 may measure the response voltage of the waste battery module 2.

For example, the voltage measurement unit 33 may measure the response resistance of the waste battery module 2 including a resistance distribution circuit. Here, the resistance distribution circuit may be a circuit for implementing a 4-terminal probe measurement method. In the 4-terminal probe measurement method, current flows through two terminals and voltage is measured through two other terminals. In the case of the waste battery module 2, the impedance of the battery module 2 is very small, from several tens of millimeters to several milli-ohms. Therefore, the voltage measuring unit 33 can measure the response voltage of the waste battery module 2 while minimizing the influence of the resistance of the lead wire by adopting a 4-terminal probe measurement method, which is the impedance of the waste battery module 2 It will be possible to increase the accuracy of the calculation.

The response signal processor 50 may calculate the impedance of the waste battery module 2 for each frequency of the perturbation signal using the response signal.

The response signal processing unit 50 may be configured on a DAQ board, and may receive a response current and a response voltage from the sensor unit 30, respectively. The response signal processing unit 50 may convert a response current and a response voltage applied from the sensor unit 30 to digital data including a digital lock-in AMP. In the following description, the response current and the response voltage are collectively referred to as response signals.

The response signal processing unit 50 may remove noise by leaving only a DC component from the response signal, and calculate the magnitude and phase of the response signal from which the noise has been removed to calculate the impedance of the waste battery module 2.

Specifically, the response signal processing unit 50 may generate a reference signal that is divided into an in-phase component having the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal.

For example, the response signal processing unit 50 may acquire an n-th response signal having N number of sampled data, and noise may be included in the response signal.

In Equation 3, M(n) denotes an n-th response signal having N number of sampled data, f _m and f _s denote a measurement frequency and a sampling frequency, respectively, and k(n) denotes a noise signal.

The response signal processing unit 50 may generate a reference signal as shown in Equation 4 below from the response signal as shown in Equation 3.

The response signal processing unit 50 calculates the real and imaginary components of the response signal M(n) by multiplying the response signal M(n) by the reference signals r _p (n) and r _Q (n), respectively. can do.

For example, the response signal processing unit 50 calculates a real component of the response signal as shown in Equation 5 below by multiplying Equation 3 by a reference signal of an in-phase component of the same phase as the response signal described in Equation 4, The imaginary component of the response signal can be calculated as shown in Equation 6 below by multiplying 3 by the response signal described in Equation 4 and the reference signal of the ideal component having a phase difference of 90 degrees.

The response signal processing unit 50 may obtain a response signal from which noise is removed by taking average values of the real component (M _real (n)) and the imaginary component (M _imag (n)) of the response signal, respectively. When the average value is taken for the real component (M _real (n)) and the imaginary component (M _imag (n)) of the response signal, the AC component converges to zero, leaving only the DC component. Accordingly, the response signal processing unit 50 may obtain a real component and an imaginary component of the response signal from which noise is removed.

For example, the response signal processing unit 50 may obtain a real component (M _real (n)) and an imaginary component (M _imag (n)) of the response signal from which noise is removed as shown in Equations 7 and 8 below. .

The response signal processing unit 50 may calculate a magnitude and a phase value of the response signal using the real component (X(n)) and the imaginary component (Y(n)) of the response signal from which noise is removed.

)을 산출할 수 있다.For example, the response signal processing unit 50 uses Equations 7 and 8 as in Equation 9 below to determine the magnitude (A) and phase value (

) Can be calculated.

)으로부터 폐 배터리 모듈(2)의 섭동 신호의 주파수 별 임피던스를 산출할 수 있다.The response signal processing unit 50 includes a magnitude (A) and a phase value (

), it is possible to calculate the impedance for each frequency of the perturbation signal of the waste battery module 2.

)을 아래 수학식 10에 대입하여 폐 배터리 모듈(2)의 주파수 별 임피던스를 산출할 수 있다.In addition, the response signal processing unit 50 is the magnitude (A) and the phase value of the response signal calculated according to Equation 9 (

) Can be substituted for Equation 10 below to calculate the impedance for each frequency of the waste battery module 2.

At this time, the response signal processing unit 50 may calculate the magnitude of the response current and the phase value of the response current with respect to the response current measured by the current measuring unit 31, and the response signal processing unit 50 is the voltage measuring unit 33 It can be understood that the magnitude of the response voltage and the phase value of the response voltage can be calculated for the response voltage measured at.

In this way, the response signal processing unit 50 may calculate the magnitude and phase value of the response signal from which noise has been removed, and calculate the impedance of the waste battery module 2 by using this.

The impedance spectrum measuring unit 70 may measure the impedance spectrum of the waste battery module 2 and display it in the form of a Nyquist plot.

The impedance spectrum measurement unit 70 may perform curve fitting using a Nyquist plot representing an impedance spectrum for each frequency of the waste battery module 2 and an equivalent circuit model. The impedance spectrum measurement unit 70 may calculate a parameter of each element as shown in FIG. 3 showing an equivalent circuit model of the waste battery module 2 as a parameter of the waste battery module 2.

6 is an example of a screen output from the impedance spectrum measuring unit shown in FIG. 4.

Referring to FIG. 6, the impedance spectrum measurement unit 70 may output a Nyquist plot of the waste battery module 2. To this end, the impedance spectrum measurement unit 70 may be implemented including a display module or may be connected to a separate display module by wire or wirelessly.

The impedance spectrum measurement unit 70 may calculate and output parameters of the waste battery module 2 using the Nyquist plot and the equivalent circuit model as well as the Nyquist plot of the waste battery module 2.

In addition, the impedance spectrum measurement unit 70 may predict the remaining life of the waste battery module 2 by comparing the parameters of the waste battery module 2 with the parameters of the new battery module.

The impedance spectrum measurement unit 70 may build a database storing the remaining life of each waste battery module 2. The impedance spectrum measurement unit 70 may group and manage the waste battery modules 2 whose residual life difference is less than or equal to a preset reference value, and arrange and manage the waste battery modules 2 in ascending or descending order of the residual life. . Accordingly, the impedance spectrum measurement unit 70 may provide information on a plurality of waste battery modules 2 having similar residual lifespans so that they can be used in an energy storage device.

Hereinafter, a method of measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention will be described.

The impedance spectrum measurement method of the waste battery module according to an embodiment of the present invention may be performed under substantially the same configuration as the impedance spectrum measurement apparatus 1 according to the embodiment of the present invention shown in FIG. 4. Therefore, the same components as those of the device 1 of FIG. 4 are given the same reference numerals, and repeated descriptions are omitted.

7 is a flowchart of a method of measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention.

Referring to FIG. 7, the perturbation inducing unit 10 may apply a perturbation signal to the waste battery module 2 (S100 ).

The perturbation inducing unit 10 may generate a perturbation voltage of a sinusoidal waveform. In addition, the perturbation induction unit 10 may convert the perturbation voltage into perturbation current and apply it to the waste battery module 2.

The sensor unit 30 may measure a response signal of the waste battery module 2 (S200).

The sensor unit 30 may measure a response signal of the waste battery module 2 to the perturbation signal. The response signal can be divided into response current and response voltage.

The response signal processing unit 50 may calculate the impedance of the waste battery module 2 by using the response signal (S300).

The response signal processing unit 50 may receive a response current and a response voltage from the sensor unit 30, respectively. The response signal processing unit 50 may convert a response current and a response voltage applied from the sensor unit 30 into digital data. The response signal processing unit 50 may remove noise by leaving only a DC component from the response signal, and calculate the magnitude and phase of the response signal from which the noise has been removed to calculate the impedance of the waste battery module 2.

Specifically, the response signal processing unit 50 may generate a reference signal that is divided into an in-phase component having the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal. The response signal processing unit 50 may calculate a real component and an imaginary component of the response signal by multiplying the response signal by a reference signal, respectively. The response signal processing unit 50 may obtain a response signal from which noise is removed by taking an average value of the real component and the imaginary component of the response signal, respectively. When an average value is taken for each real component and imaginary component of the response signal, the AC component converges to zero, leaving only the DC component. Accordingly, the response signal processing unit 50 may obtain a real component and an imaginary component of the response signal from which noise has been removed.

The response signal processing unit 50 may calculate a magnitude and a phase value of the response signal using real and imaginary components of the response signal from which noise is removed. The response signal processor 50 may calculate an impedance for each frequency of the perturbation signal of the waste battery module 2 from the magnitude and phase value of the response signal.

The impedance spectrum measurement unit 70 may calculate an impedance spectrum of the waste battery module 2 (S400).

The impedance spectrum measuring unit 70 may show the impedance for each frequency of the waste battery module 2 and output it in the form of a Nyquist plot. The impedance spectrum measurement unit 70 may calculate a parameter of each element as shown in FIG. 3 showing an equivalent circuit model of the waste battery module 2 as a parameter of the waste battery module 2.

The impedance spectrum measurement unit 70 may calculate and output parameters of the waste battery module 2 by using the Nyquist plot and the equivalent circuit model of the waste battery module 2.

Hereinafter, an effect of a method for measuring an impedance spectrum of a waste battery module according to an embodiment of the present invention will be described.

The method of measuring the impedance spectrum of the waste battery module according to an embodiment of the present invention has high accuracy in measuring the impedance spectrum of the waste battery module. To verify this, four Bexel pouch cells were connected in series to produce a waste battery module with a nominal capacity of 32 Ah and a nominal voltage of 14.8V. In addition, the impedance spectrum of the waste battery module was measured by the impedance spectrum measuring apparatus 1 and the commercial equipment (BIM2) according to an embodiment of the present invention.

In both the impedance spectrum measuring apparatus 1 and commercial equipment according to an embodiment of the present invention, linearity was ensured by selecting the perturbation current to be 2Ap-p within 5% of the charge amount, and the terminal voltage of the waste battery module during measurement was 14.921. V, and the experiment was conducted at room temperature (24.5 degrees).

8 is a diagram showing an impedance spectrum measured using an apparatus for measuring an impedance spectrum of a waste battery module and commercial equipment according to an embodiment of the present invention.

Referring to FIG. 8, it can be seen that the impedance spectrum measured by the apparatus 1 for measuring the impedance spectrum of the waste battery module according to an embodiment of the present invention and the impedance spectrum measured using commercial equipment are substantially the same.

In general, reproducibility is considered as an important factor in determining the accuracy of an electrochemical impedance spectroscopy device (EIS instrument). Reproducibility is to check whether the same result is produced when the same measurement object is tested under the same test conditions, and is calculated as Reduced Chi-Square according to Equation 11 below.

The correlation between the impedance spectrum measured by the impedance spectrum measuring apparatus 1 of the waste battery module according to an embodiment of the present invention and the impedance spectrum measurement result measured using commercial equipment was calculated according to Equation 11 Is 1.8443%, indicating that the correlation between the measurement results of the two instruments is very close and is almost the same.

That is, the apparatus 1 for measuring impedance spectrum of a waste battery module according to an exemplary embodiment of the present invention can secure high accuracy in measuring the impedance spectrum of the waste battery module.

As described above, the method of measuring the impedance spectrum of the waste battery module of the present invention may be implemented as an application or implemented in the form of program instructions that can be executed through various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

The program instructions recorded in the computer-readable recording medium may be specially designed and constructed for the present invention, and may be known and usable to those skilled in the computer software field.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magnetic-optical media such as floptical disks. media), and a hardware device specially configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform processing according to the present invention, and vice versa.

Although the above has been described with reference to embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

1: Impedance spectrum measurement device of waste battery module
2: waste battery module

Claims (12)

A perturbation inducing unit generating a perturbation signal and applying it to the waste battery module;
A sensor unit measuring a response signal of the waste battery module to the perturbation signal;
A response signal processor for calculating an impedance of the waste battery module for each frequency of the perturbation signal using the response signal; And
Impedance spectrum measurement device of a waste battery module comprising an impedance spectrum measurement unit for displaying the impedance spectrum of the waste battery module for each frequency of the perturbation signal in the form of a Nyquist plot. The method of claim 1,
The response signal processing unit,
Impedance spectrum measuring apparatus of a waste battery module for removing noise by leaving only a DC component in the response signal, and calculating an impedance of the waste battery module by calculating a magnitude and a phase of the response signal from which noise is removed. The method of claim 2,
The response signal processing unit,
Generating a reference signal divided into an in-phase component of the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal, and multiplying the response signal by the reference signal, respectively, to calculate a real component and an imaginary component of the response signal And calculating the response signal from which noise is removed by taking an average value of each of the real component and the imaginary component of the response signal. The method of claim 1,
The sensor unit,
A current measuring unit measuring a response current of the waste battery module using a shunt resistance; And
Impedance spectrum measuring apparatus of a waste battery module comprising a voltage measuring unit for measuring the response voltage of the waste battery module using a resistance distribution circuit. The method of claim 4,
The voltage measuring unit,
Impedance spectrum measuring device of a waste battery module for measuring the response voltage by a 4-terminal probe measurement method that applies a current through two terminals and measures a voltage through two terminals. The method of claim 1,
The impedance spectrum measuring unit,
Impedance spectrum measuring apparatus of a waste battery module for calculating and displaying parameters of elements constituting an equivalent circuit model corresponding to the impedance spectrum. In the impedance spectrum measurement method in the impedance spectrum measurement device for the residual horizontal evaluation of the waste battery module,
Generating a perturbation signal and applying it to a waste battery module;
Measuring a response signal of the waste battery module to the perturbation signal;
Calculating the impedance of the waste battery module for each frequency of the perturbation signal using the response signal; And
Impedance spectrum measurement method of a waste battery module comprising the step of displaying the impedance spectrum of the waste battery module for each frequency of the perturbation signal in the form of a Nyquist plot. The method of claim 7,
Calculating the impedance of the waste battery module for each frequency of the perturbation signal using the response signal,
Removing noise by leaving only a DC component in the response signal; And
And calculating the impedance of the waste battery module by calculating the magnitude and phase of the response signal from which noise has been removed. The method of claim 8,
The step of removing noise by leaving only a DC component in the response signal,
Generating a reference signal divided into an in-phase component having the same phase as the response signal and an ideal component having a phase difference of 90 degrees from the response signal;
Calculating a real component and an imaginary component of the response signal by multiplying the response signal by the reference signal, respectively; And
And calculating the response signal from which noise is removed by taking an average value of the real component and the imaginary component of the response signal, respectively. The method of claim 7,
Measuring the response signal of the waste battery module to the perturbation signal,
Impedance spectrum measurement method of a waste battery module comprising the step of measuring a response voltage of the waste battery module by a 4-terminal probe measurement method of applying a current to two terminals and measuring a voltage through the two terminals. The method of claim 7,
Displaying the impedance spectrum of the waste battery module for each frequency of the perturbation signal in the form of a Nyquist plot,
And calculating and displaying a parameter of an element constituting an equivalent circuit model corresponding to the impedance spectrum. A computer-readable recording medium having a computer program recorded thereon for performing the method of measuring an impedance spectrum of a waste battery module according to claim 7.

Images