KR20220074258A - Apparatus and method for reusable battery diagnostic - Google Patents

Abstract

A reuse battery diagnostic device according to a technical aspect of the present invention is a reuse battery diagnostic device for determining a health state and a charge state of a reuse battery, and receives an input voltage and an input current, and receives a fundamental wave from the input voltage and the input current A band-pass filter for detecting a component, a multiplier for multiplying the output of the band-pass filter, a peak value calculator for receiving the output of the band-pass filter and calculating a peak value, receiving the output of the multiplier as an input, maximum and minimum values receiving the output of the maximum and minimum calculator and the peak value calculator and the output of the maximum and minimum calculator for calculating and a calculator to calculate the electrolytic transfer resistance Rd and the charge double layer capacitor Cd by separating them into reactive components.

Description

Reusable Battery Diagnostic Apparatus and Method {APPARATUS AND METHOD FOR REUSABLE BATTERY DIAGNOSTIC}

The present invention relates to an apparatus and method for diagnosing a reusable battery.

As the domestic electric vehicle supply plan expands from 12,000 units in 2016 to 350,000 units by 2022, the amount of waste batteries is expected to increase rapidly, but any standards or technologies for the reuse system for waste batteries are insufficient.

Since these waste batteries also contain environmental risks when disposed of, the need for a technology for diagnosing reusable batteries based on performance tests of the waste batteries is growing.

As a conventional battery diagnosis technology, there is a method of diagnosing using a DCIR (Direct Current Internal Resistance) method by inputting a two-stage current.

Such a DCIR (Direct Current Internal Resistance) method has a problem in that the measurement accuracy becomes more precise as the current difference of the level increases, but the internal resistance changes according to the charging current level. There is a problem in that it is difficult to guarantee the precision of the state-of-health (SOH) of the battery by using only the battery.

Korean Patent Publication No. 10-2016-0080802

One technical aspect of the present invention is to solve the problems of the prior art, and to prevent changes in internal resistance by applying ACIR (Alternative Current Internal Resistance), and to prevent a change in internal resistance and the remaining life of the battery (state-of-health, It is to provide an apparatus and method for diagnosing a reuse battery capable of accurately calculating SOH).

In addition, one technical aspect of the present invention, by applying high frequency and low frequency to ACIR (Alternative Current Internal Resistance), efficiently measure the recyclability of the battery by solving the difficulties of the low frequency sensing sensitivity while efficiently performing numerical calculations. It is to provide an apparatus and method for diagnosing a reusable battery that can do this.

The above objects and various advantages of the present invention will become more apparent from preferred embodiments of the present invention by those skilled in the art.

One technical aspect of the present invention proposes an apparatus for diagnosing a reuse battery. The reusable battery diagnosis apparatus is a reusable battery diagnosis apparatus that determines a health state and a charge state of a reused battery, and receives an input voltage and an input current, and detects a fundamental wave component from the input voltage and the input current. , a multiplier that multiplies the output of the band pass filter, a peak value calculator that receives the output of the band pass filter and calculates a peak value, a maximum and minimum calculator that receives the output of the multiplier and calculates maximum and minimum values and receiving the output of the peak value calculator and the output of the maximum and minimum calculator, calculating the electrolyte resistance Ri using the voltage peak value and the current peak value, and dividing the input current into an active component and an ineffective component for electrolysis It may include a calculator to calculate the transfer resistance Rd and the charge double layer capacitor Cd.

In an embodiment, the apparatus for diagnosing the reuse battery may calculate the electrolyte resistance Ri by receiving a high frequency signal having a capacitive impedance value of zero.

In an embodiment, the apparatus for diagnosing a reuse battery may receive a low frequency having a capacitive impedance value corresponding to the electrolytic transfer resistor Rd to calculate the electrolytic transfer resistor Rd and the charge double-layer capacitor Cd.

In an embodiment, the peak value calculator includes an absolute value calculator that receives the output of the band-pass filter and calculates an absolute value, and a low-pass filter that receives the output of the absolute value calculator and performs low-pass filtering. may include

In an embodiment, the band pass filter may include a first band pass filter receiving the input voltage and a second band pass filter receiving the input current.

In an embodiment, the absolute value calculator includes: a first absolute value calculator that receives an output of the first band-pass filter to calculate an absolute voltage value; and a first absolute value calculator that receives an output of the second band-pass filter and calculates an absolute current value and a second absolute value calculator for calculating, wherein the low-pass filter receives the output of the first absolute value calculator and receives the output of the first low-pass filter for performing low-pass filtering and the output of the second absolute value calculator It may include a second low-pass filter that receives the input and performs low-pass filtering.

Another technical aspect of the present invention proposes a method for diagnosing a reuse battery. The reuse battery diagnosis method includes: receiving an input voltage and an input current, performing band-pass filtering on the input voltage and the input current to detect a fundamental wave; receiving and multiplying the fundamental wave; Calculating a peak value by receiving a wave, calculating a maximum value and a minimum value based on the result of the multiplication step, and calculating the electrolyte resistance Ri using the voltage peak value and the current peak value. can

In an embodiment, the method for diagnosing a reuse battery may further include calculating an electrolytic transfer resistance Rd and a charge double-layer capacitor Cd by dividing the current into an active component and an ineffective component.

In an embodiment, the calculating of the electrolyte resistance Ri may be performed by applying a high frequency corresponding to a capacitive impedance value of zero.

In an embodiment, the calculating of the electrolytic transfer resistor Rd and the charge double-layer capacitor Cd may be performed by receiving a low frequency corresponding to the electrolytic transfer resistor Rd with a capacitive impedance value.

The means for solving the above-described problems do not enumerate all the features of the present invention. Various means for solving the problems of the present invention may be understood in more detail with reference to specific embodiments in the following detailed description.

According to an embodiment of the present invention, there is an effect of preventing a change in internal resistance by applying ACIR (Alternative Current Internal Resistance) and accurately calculating the remaining life of the battery (state-of-health, SOH). have.

In addition, according to an embodiment of the present invention, by applying a high frequency and a low frequency to ACIR (Alternative Current Internal Resistance), numerical calculations are efficiently performed and the difficulty of the low frequency sensing sensitivity is solved, so that the recyclability of the battery is more accurately improved. It has a measurable effect.

1 shows the electrochemical reaction inside the battery. An electrical model is shown, and FIG. 2 shows a simplified impedance model of the battery.
3 and 4 are graphs showing the internal parameter characteristics of the battery.
5 is a diagram for explaining a method of estimating a battery parameter using direct current internal resistance (DCIR).
6 is a diagram illustrating an impedance model of a battery according to an embodiment of the present invention.
7 is a block diagram illustrating an apparatus for diagnosing a reuse battery according to an embodiment of the present invention.
FIG. 8 is a diagram illustrating an embodiment of the apparatus for diagnosing a reuse battery shown in FIG. 7 .
9 is a diagram showing an example of an impedance trajectory for estimating target values Ri, Rd and Cd.
Fig. 10 is a diagram for explaining high-frequency detection using a band-pass filter.
It is a figure for demonstrating calculation of the parameter by a high frequency power supply.
12 is a diagram for explaining calculation of a parameter by a low-frequency power supply.
13 is a diagram illustrating an example of the maximum value calculator and the minimum value calculator shown in FIG. 8 .
14 is a measurement block diagram in which parameters Rd and Cd can be measured.
15 is a flowchart illustrating a method for diagnosing a reuse battery according to an embodiment of the present invention.

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

However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided in order to more completely explain the present invention to those of ordinary skill in the art.

That is, the above-described objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, a person of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Also, as used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or various steps described in the specification, some of which components or some steps are It should be construed that it may not include, or may further include additional components or steps.

In addition, various components and sub-components thereof are described below in order to describe the system according to the present invention. These components and sub-components thereof may be implemented in various forms, such as hardware, software, or a combination thereof. For example, each element may be implemented as an electronic configuration for performing a corresponding function, or may be software itself operable in an electronic system or implemented as a functional element of such software. Alternatively, it may be implemented with an electronic configuration and corresponding driving software.

The various techniques described herein may be implemented with hardware or software, or a combination of both, where appropriate. As used herein, terms such as "Unit", "Server" and "System" likewise refer to computer-related entities, i.e. hardware, a combination of hardware and software, software or It can be treated as equivalent to software at the time of execution. In addition, each function executed in the system of the present invention may be configured in units of modules, and may be recorded in one physical memory, or may be recorded while being dispersed between two or more memories and recording media.

Although various flowcharts are disclosed to describe the embodiments of the present invention, this is for convenience of description of each step, and each step is not necessarily performed according to the order of the flowchart. That is, each step in the flowchart may be performed simultaneously with each other, performed in an order according to the flowchart, or may be performed in an order opposite to the order in the flowchart.

Hereinafter, an apparatus and method for diagnosing a reuse battery according to some embodiments of the present invention will be described.

1 shows the electrochemical reaction inside the battery. An electrical model is shown, and FIG. 2 shows a simplified impedance model of the battery.

In general, the time, temperature, and voltage required for repeated charging and discharging are measured and used as a standard for evaluating the battery condition. However, there is a disadvantage that the voltage alone cannot reflect the detailed characteristics of the internal battery.

Impedance is interpreted as a cause that interferes with electrical transmission when a chemical (oxidation-reduction) reaction occurs in the electrode, and impedance can be analyzed to perform battery analysis accurately and quickly.

The electrochemical process inside the battery can be expressed as an electrical model as shown in FIG. 1 , and such an electrical model consists of several components, namely, a resistor, a capacitor, an inductor, a delay time, etc. and has complex and non-linear characteristics.

As shown in FIG. 2 , the state of the battery is analyzed by applying Randles modeling, which is a simplified impedance model, to the battery.

Ri is an electrolyte resistance, which means Ohm resistance inside a battery (eg, an electrode, an electrolyte), and as the change period of voltage and current increases, it has a dominant influence on battery characteristics. Because of this characteristic, Ri is also called AC resistance. The Ri value increases as the performance deteriorates due to the aging phenomenon of the battery. Therefore, Ri is a criterion for determining the state of health (SOH) of the battery.

Rd is the charge transfer resistance, and Cd is the electric double layer capacitor. Rd and Cd are standards for determining the state of charge (SoC) of the battery.

The impedance of the battery in the impedance model shown in FIG. 2 can be expressed as Equation 1 below.

[Equation 1]

3 and 4 are graphs showing the internal parameter characteristics of the battery.

Figure 3 (a) is a graph relating to the deterioration characteristics of the battery according to the C-rate and the depth of discharge. In general, in a battery, the higher the C-rate, the greater the decrease in capacity, and the greater the depth of discharge (DOD), the greater the decrease in maximum output power.

Therefore, in order to use the battery efficiently, it is necessary to lower the C-rate and the depth of discharge.

As shown in Figure 3 (b), the increase in the depth of discharge (DOD) increases the output power reduction ratio. Therefore, it is necessary to design according to the use of the battery or the purpose of using the system. The maximum output value is determined by the maximum value of the load, and the battery capacity is determined by the integration of the load pattern.

As shown in Fig. 4 (a), the internal resistance of the battery changes according to the C-rate, temperature, and SOC (State of Charge). Therefore, the internal resistance is used as a parameter to estimate SOC and SOH. It is possible.

In the case of battery aging, it can be seen that the aging of the battery life (the number of times of charging and discharging) is accelerated according to the high ambient temperature and high charging/discharging current and shape, and the internal resistance of the battery sharply increases with aging.

Figure 4 (b) is a curve showing the SOC on the horizontal axis and the OCV (terminal voltage in the open state) of the battery on the vertical axis, that is, the voltage when no current is applied. The terminal voltage in the open state corresponds to the difference between the positive and negative potentials in the open state. The graph may vary depending on the balance between the positive-negative active material and the positive-negative electrode used in the battery.

As a result, the SOH of the current battery is determined by comparing it with the initially measured state value based on the state value that changes as the battery is used. The standard for the definition of battery SOH has not yet been decided because battery application fields are very diverse and performance standards are very different for each field.

In an embodiment of the present invention, the representative parameters (Ri, Rd, Cd) of the xEV reused battery are estimated by a new method, the reused battery is compared with a new product, the performance is verified, and the feasibility of reuse is determined.

5 is a diagram for explaining a method of estimating a battery parameter using direct current internal resistance (DCIR) using a two-level current as a comparative example.

When a two-stage current is input as shown in Fig. 5 (a), Zc becomes infinite, and is equalized to an open circuit as shown in Fig. (b), resulting in the synthesis of solution resistance and charge transfer resistance, as shown in Equation 2 below is satisfied with

[Equation 2]

Figure (c) shows the battery terminal voltage and current during pulse charging to measure DCIR. In the two-level constant current mode, DCIR for each terminal voltage and current is defined as in Equation 3 below.

[Equation 3]

In the 2-level constant current charging mode, level 1 is the same as the existing constant current charging, and level 2 is a mode added to follow the parameters of the battery in real time.

The battery internal voltage is defined as in Equation 4 below.

[Equation 4]

As a result, the greater the level current difference, the more precise the measurement accuracy, but the internal resistance changes according to the charging current level, and DCIR uses only information about the sum of the two resistances in the Randles model equivalent circuit.

As a result, when DCIR is used, there is a problem in that it is difficult to guarantee precision for SOH.

In order to solve this problem, the present invention provides measurement and evaluation of a battery by applying ACIR (Alternative Current Internal Resistance) using two types of frequencies.

That is, two types of frequencies are applied to measure the impedance.

Here, the choice of two types of frequencies is important. In general, the frequency band used for impedance measurement is between 10 mHz and 1 KHz, but when two types of frequencies are applied in this range, there are problems in that the numerical calculation is complicated and the sensing sensitivity is lowered at low frequencies.

Therefore, in the present invention, as two types of frequencies, a high frequency (first frequency) having a capacitive impedance value close to zero, that is, a capacitive impedance value corresponding to zero, and a capacitive impedance value similar to Rd, That is, a method of measuring the capacitive impedance value using a low frequency (second frequency) corresponding to Rd is proposed.

6 is a diagram illustrating a circuit diagram of a battery as viewed from an input terminal.

As described above, the DCIR measurement method has a problem in that a long time is required to measure Rd because the time constant (Tc) increases in the Randles model equivalent circuit.

Accordingly, in one embodiment of the present invention, ACIR using high frequency and low frequency is applied, which is information of voltage and current having two or more heterogeneous frequencies in order to measure three parameters by AC voltage and current in the Randles equivalent circuit. because it needs

A pulsating voltage, ie, a combined voltage of DC and AC, may be applied to the terminal of the equivalent circuit shown in FIG. 6 . In the pulsating voltage current applied to the battery, when a band pass filter (BPF) is passed to detect only the AC component, only the AC frequency component can be detected.

On the other hand, the steady-state output voltage and current of the power converter for battery charging driven by PWM (Pulse Width Modulation) includes a DC component and a high-frequency term that is a multiple of the switching frequency. is expressed

[Equation 5]

When the fundamental wave component is detected by applying a band pass filter to the input voltage and input current, it is expressed as in Equation 6 below.

[Equation 6]

After all, in the battery AC equivalent circuit proposed in the present invention, the impedance is expressed as in Equation 7 below.

[Equation 7]

7 is a block diagram illustrating an apparatus for diagnosing a reuse battery according to an embodiment of the present invention.

Referring to FIG. 7 , the reuse battery diagnosis apparatus 100 includes a band pass filter 110 , a peak value calculator 120 , a multiplier 130 , a maximum minimum calculator 140 , and a calculator 150 .

The band pass filter 110 receives an input voltage and an input current, and detects a fundamental wave component from the input voltage and the input current.

The multiplier 130 multiplies the output of the band pass filter.

The peak value calculator 120 receives the output of the band pass filter and calculates a peak value.

The maximum and minimum calculator 140 receives the output of the multiplier and calculates maximum and minimum values.

The calculator 150 receives the output of the peak value calculator and the output of the maximum and minimum calculator, calculates the electrolyte resistance Ri using the voltage peak value and the current peak value, and separates the input current into an active component and an invalid component to calculate the electrolytic transfer resistance Rd and the charge double layer capacitor Cd.

As described above, the reuse battery diagnosis apparatus 100 receives a high frequency corresponding to a capacitive impedance value of zero, calculates an electrolyte resistance Ri, and applies a low frequency whose capacitive impedance value corresponds to the electrolytic transfer resistance Rd. can be taken to yield an electrolytic transfer resistance Rd and a charge double layer capacitor Cd.

FIG. 8 is a diagram illustrating an embodiment of the apparatus for diagnosing a reuse battery shown in FIG. 7 .

Referring to FIG. 8 , the band-pass filter 100 includes a first band-pass filter receiving an input voltage and a second band-pass filter receiving an input current.

The peak value calculator 120 receives the output of the band-pass filter and calculates an absolute value, and the low-pass filter 122 receives the output of the absolute value calculator and performs low-pass filtering. may include

The absolute value calculator 121 receives the output of the first band-pass filter as an input and calculates an absolute voltage value as a first absolute value calculator, and receives the output of the second band-pass filter and calculates an absolute current value. It may include an absolute value calculator.

The low-pass filter 122 receives the output of the first absolute value calculator and performs low-pass filtering. The low-pass filter 122 receives the output of the second absolute value calculator and performs low-pass filtering. It may include a pass filter.

The maximum and minimum calculator 140 may include a maximum value calculator and a minimum value calculator, and FIG. 13 shows an example of the maximum value calculator and the minimum value calculator shown in FIG. 8 .

Hereinafter, the reuse battery diagnosis apparatus 100 will be described in more detail with reference to FIGS. 9 to 14 .

9 is a diagram showing an example of an impedance trajectory for estimating target values Ri, Rd and Cd.

In order to estimate the target value Ri, a high frequency component in which the capacitive reactance becomes almost zero is applied to estimate Ri.

In addition, in order to estimate the target values Rd and Cd, a low frequency corresponding to the capacitive impedance value Rd is applied, and the Rd and Cd values are estimated by separating them into inactive components.

Fig. 10 is a diagram for explaining high-frequency detection using a band-pass filter.

Figure (a) is the waveform of the input voltage V _in (t) of the band-pass filter, Figure (b) is the waveform of the output voltage of the band-pass filter, V _b (t), Figure (c) is the voltage peak (V _peak ) ) and the current peak (i _peak ) are respectively indicated.

The input voltage V _in (t) of the band pass filter, the output voltage V _b (t) of the band pass filter, the output current i _b (t), the voltage peak V _peak and the current peak i _peak are obtained by the following Equations 8 to 11 Satisfies.

[Equation 8]

[Equation 9]

[Equation 10]

[Equation 11]

It is a figure for demonstrating calculation of the parameter by a high frequency power supply.

Fig. 11 shows a high-frequency power supply, which is for a high-frequency power supply in which the capacitive impedance is almost zero, that is, the capacitive impedance corresponds to zero, and Ri is detected using this high-frequency power supply.

Assuming that the power supply frequency is a very large frequency at which the capacitive impedance is almost zero, the fundamental wave current is defined as in Equation 12 below.

[Equation 12]

When the current of the bandpass filter is defined as in Equation 12, the battery parameter Ri satisfies Equation 13 below.

[Equation 13]

Here, the power condition in which the voltage and the current must be in phase satisfies Equations 14 to 18 below.

[Equation 14]

[Equation 15]

[Equation 16]

[Equation 17]

[Equation 18]

12 is a diagram for explaining calculation of a parameter by a low-frequency power supply.

Figure 12 (a) satisfies the following Equations 19 and 20.

[Equation 19]

[Equation 20]

If the parameter Ri is measured in the high frequency power supply, the voltage at the capacitor Cd satisfies Equation 21 below.

[Equation 21]

If the current (i ₁ ) of the battery is developed with a Fourier series based on the capacitor voltage phase, it is possible to separate the active current component flowing through the resistor in phase with the capacitor voltage and the ineffective component having a 90 degree phase with the capacitor voltage. Figure (b) shows these active ingredients i _q and inactive ingredients i _d . If this is described mathematically, Equations 22 to 24 below are satisfied.

[Equation 22]

[Equation 23]

[Equation 24]

14 is a block diagram of a measurement capable of measuring the parameters Rd and Cd, which may correspond to the calculator shown in FIGS. 7 and 8 .

The calculator 150 receives the filtered voltage and current. V _c is calculated by subtracting the voltage from the parameter Ri calculated through high frequency, and a phase-locked loop (PLL) and discrete Fourier transform (DFT) are applied to the calculated V _c . The parameters wCd and Rd can be calculated by reflecting each V _c in the output value of the discrete Fourier transform (DFT).

In the above, various embodiments of the apparatus for diagnosing a reuse battery have been described with reference to FIGS. 1 to 14 .

Hereinafter, a method for diagnosing a reuse battery according to an embodiment of the present invention will be described with reference to FIG. 15 .

Since the reuse battery diagnosis method to be described below is performed by the reuse battery diagnosis apparatus described with reference to FIGS. 1 to 14 , it can be more easily understood with reference to the description described above with reference to FIGS. 1 to 14 .

15 is a flowchart illustrating a method for diagnosing a reuse battery according to an embodiment of the present invention.

Referring to FIG. 15 , the reuse battery diagnosis apparatus 100 may receive an input voltage and an input current, and may detect a fundamental wave by performing band-pass filtering on the input voltage and input current ( S1510 ).

The reuse battery diagnosis apparatus 100 may receive a fundamental wave and multiply (S1520).

The reuse battery diagnosis apparatus 100 may receive a fundamental wave and calculate a peak value (S1530).

The reuse battery diagnosis apparatus 100 may calculate a maximum value and a minimum value based on the result of the multiplication step (S1540).

The reuse battery diagnosis apparatus 100 may calculate the electrolyte resistance Ri by using the voltage peak value and the current peak value (S1550).

The reuse battery diagnosis apparatus 100 may calculate the electrolytic transfer resistance Rd and the charge double layer capacitor Cd by separating the current into an active component and an ineffective component (S1560).

In an embodiment, the reuse battery diagnosis apparatus 100 may calculate the electrolyte resistance Ri by receiving a high frequency corresponding to zero capacitive impedance.

In an embodiment, the apparatus 100 for diagnosing a reuse battery may calculate an electrolytic transfer resistor Rd and a charge double-layer capacitor Cd by receiving a low frequency having a capacitive impedance value corresponding to the electrolytic transfer resistor Rd.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, but is limited by the claims described below, and the configuration of the present invention may vary within the scope without departing from the technical spirit of the present invention. Those of ordinary skill in the art to which the present invention pertains can easily recognize that it can be easily changed and modified.

100: Reusable battery diagnostic device
110: band pass filter 120: peak value calculator
130: multiplier 140: maximum minimum calculator
150: calculator

Claims (10)

A reuse battery diagnostic device for determining the health status and charge status of a reuse battery,
a band pass filter receiving an input voltage and an input current, and detecting a fundamental component from the input voltage and the input current;
a multiplier for multiplying the output of the band pass filter;
a peak value calculator that receives the output of the band pass filter and calculates a peak value;
a maximum and minimum calculator that receives the output of the multiplier and calculates maximum and minimum values; and
The output of the peak value calculator and the output of the maximum and minimum calculator are received, the electrolyte resistance Ri is calculated using the voltage peak value and the current peak value, and the received current is separated into an active component and an ineffective component and electrolytically transmitted a calculator to calculate the resistance Rd and the charge double layer capacitor Cd;
Reusable battery diagnostic device comprising a.
According to claim 1,
The reusable battery diagnostic device is
Calculating the electrolyte resistance Ri by receiving a high frequency corresponding to zero capacitive impedance
Reusable battery diagnostic device, characterized in that.
3. The method of claim 2,
The reusable battery diagnostic device is
Calculating the electrolytic transfer resistance Rd and the charge double-layer capacitor Cd by receiving a low frequency having a capacitive impedance value corresponding to the electrolytic transfer resistance Rd
Reusable battery diagnostic device, characterized in that.
According to claim 1,
The peak value calculator
an absolute value calculator that receives the output of the band pass filter and calculates an absolute value; and
a low-pass filter receiving the output of the absolute value calculator and performing low-pass filtering;
Reusable battery diagnostic device comprising a.
5. The method of claim 4,
The band pass filter is
a first band-pass filter receiving the input voltage; and
a second band-pass filter receiving the input current;
Reusable battery diagnostic device comprising a.
6. The method of claim 5,
The absolute value calculator
a first absolute value calculator for receiving an output of the first band pass filter and calculating an absolute voltage value; and
a second absolute value calculator for receiving an output of the second band pass filter and calculating an absolute current value;
including,
The low pass filter is
a first low-pass filter receiving the output of the first absolute value calculator and performing low-pass filtering; and
a second low-pass filter receiving the output of the second absolute value calculator and performing low-pass filtering;
Reusable battery diagnostic device comprising a.
receiving an input voltage and an input current, and performing band-pass filtering on the input voltage and the input current to detect a fundamental wave;
receiving and multiplying the fundamental wave;
receiving the fundamental wave and calculating a peak value;
calculating a maximum value and a minimum value based on the result of the multiplication; and
calculating an electrolyte resistance Ri using the voltage peak value and the current peak value;
Reusable battery diagnostic method comprising a.
8. The method of claim 7,
The method for diagnosing the reused battery is
separating the current into active and reactive components to yield an electrolytic transfer resistance Rd and a charge double layer capacitor Cd;
Reusable battery diagnosis method further comprising a.
9. The method of claim 8,
Calculating the electrolyte resistance Ri comprises:
Performed by applying a high frequency corresponding to a capacitive impedance value of zero
Reusable battery diagnostic method, characterized in that.
10. The method of claim 9,
Calculating the electrolytic transfer resistance Rd and the charge double-layer capacitor Cd comprises:
Capacitive impedance value is performed by applying a low frequency corresponding to the electrolytic transfer resistance Rd
Reusable battery diagnostic method, characterized in that.

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