KR20170141035A - Low cost impedance spectroscopy system and method capable of estimating state of health for high-voltage battery pack - Google Patents

Abstract

Various embodiments of the present invention relate to a low-cost impedance spectroscopy system and method capable of estimating a state of health (SOH) of a high-voltage battery pack. For example, various embodiments of the present invention include: a battery pack; a power amplifier for applying a perturbation current to the battery pack; a voltage measuring portion for measuring response voltage of the battery pack; a perturbation signal separation portion for removing a direct current component from a voltage signal of the battery pack by the voltage measuring portion, and separating and outputting only the AC component; and an analog-to-digital converter for converting an analog signal corresponding to the AC component of the perturbation signal separation portion into a digital signal, and outputting the digital signal.

Description

TECHNICAL FIELD [0001] The present invention relates to a low-cost impedance spectroscopy system and method capable of estimating the sound state of a high-voltage battery pack,

Various embodiments of the present invention are directed to a low cost impedance spectroscopy system and method capable of estimating the sound state of a high voltage battery pack.

 The battery of the existing internal combustion engine vehicle is estimated by estimating the internal resistance of the battery by changing the current and voltage of the battery when the vehicle is started. However, in the case of a vehicle using a high-voltage battery pack such as a recent environment-friendly vehicle (HEV / BEV), there is a problem that it is difficult to estimate the battery health state by using the existing algorithm because the battery pack does not start the vehicle or require a separate start. Therefore, it is necessary to measure the internal resistance of the battery pack in a battery pack used in an environmentally friendly automobile by means other than the vehicle start-up state. There are already many products and technologies that measure the impedance of a battery but all have been developed for cell or low voltage packs and there is no real product, patent or utility model for a system and method for measuring the impedance of a high voltage battery pack .

For example, in Korean Patent Laid-Open Publication No. 2015-0025932 entitled " Charger Having a Battery Diagnosis Function and Its Control Method "(patent 1), in order to achieve a charger capable of diagnosing the life of the battery when charging the battery and a control method thereof, A converter for applying a perturbation, and a digital signal processor for calculating an impedance spectrum and for estimating the life of the battery by comparing impedance parameters of a predetermined reference battery (see FIG. 1).

In addition, in Korean Patent Laid-Open Publication No. 2014-0013759 entitled " Method of managing battery pack for vehicle using module-impedance "(Patent 2), in order to achieve management of battery pack for vehicle using module- impedance, Impedance of a cell is measured for each cell, cell impedance is calculated for each cell, module-impedance is calculated, maximum cell-to-cell maximum deviation for each module is calculated, The module-impedance change rate is generated by storing the module-impedance of the module, thereby detecting and changing the rate of change of the impedance for each module constituting the battery pack even when the vehicle is in operation, and ultimately, And a method for detecting and managing a star-like deterioration difference (see FIG. 2).

However, in the case of Patent 1, as a technique for measuring the lifetime of a battery through impedance measured during charging by combining a charging method for measuring the impedance with a charger for charging the battery, as shown in FIG. 1, Since there is no mention of signal processing, it is possible to measure the impedance of a cell or a low-voltage battery pack having a low voltage band with this prior art technique, but there is a limit to measure the impedance of a high-voltage battery pack having a high voltage band.

Patent 2 is a technology that manages a battery pack for a vehicle using module-impedance. It measures the impedance of each battery cell and estimates the impedance of the battery pack by summing the impedance. However, impedance can be measured for each cell The cost and complexity of the system configuration has increased, and other components making up the pack in addition to the battery cell have been left out of the impedance measurement.

The above-described information disclosed in the background of the present invention is only for improving the understanding of the background of the present invention, and thus may include information not constituting the prior art.

Korean Patent Laid-Open Publication No. 2015-0025932 "Charger having battery diagnosis function and control method thereof" Korean Patent Laid-Open Publication No. 2014-0013759 "Module-impedance battery management method for vehicle" Korean Unexamined Patent Publication No. 2004-0010528 "Fuel cell impedance measuring device" Korean Patent No. 0823507 "Battery management system and driving method thereof" Korean Patent Publication No. 2014-0034717 "Battery monitoring in electric vehicles, hybrid electric vehicles and other applications" Japanese Unexamined Patent Publication No. 2006-306376 "Onboard Battery Management Device"

Various embodiments of the present invention provide a low cost impedance spectroscopy system and method capable of estimating the sound state of a high voltage battery pack. That is, various embodiments of the present invention provide a method for detecting only an AC component in a battery voltage or current signal and measuring an impedance required for estimating the health state of the high-voltage battery pack.

A low-cost impedance spectroscopy system capable of estimating the sound state of a high-voltage battery pack according to various embodiments of the present invention includes a battery pack; A power amplifier for applying a perturbation current to the battery pack; A voltage measuring unit for measuring a response voltage of the battery pack; A perturbation signal separator which removes a direct current component from the voltage signal of the battery pack by the voltage measuring unit and separates and outputs only an AC component; And an analog-to-digital converter for converting an analog signal of the AC component generated by the perturbation signal separator into a digital signal and outputting the digital signal.

The voltage measuring unit may include a voltage-dividing resistor, the perturbation signal separating unit may include a low-pass filter connected to the voltage-dividing resistor, and a differential amplifier circuit connected to the voltage-dividing resistor and the low-pass filter. The node of the voltage-dividing resistor may be connected to the inverting terminal of the differential amplifying circuit through the low-pass filter, and the node of the voltage-dividing resistor may be connected to the non-inverting terminal of the low-pass filter. And an AC signal and a DC signal can be output through the node of the voltage-dividing resistor, and only a DC signal can be output through the low-pass filter and input to an inverting terminal of the differential amplifier circuit, A signal and a DC signal can be input to the non-inverting terminal of the differential amplifying circuit. The differential amplifier circuit can output only the AC signal to the analog-to-digital converter.

The various embodiments of the present invention may further include a digital lock-in amplifier connected to the analog digital converter, and the digital lock-in amplifier may separately output a real number and an imaginary number of voltage and current. The various embodiments of the present invention may further include a battery internal impedance operation unit connected to the digital lock-up amplifier, and the battery internal impedance operation unit may calculate an impedance real part, an imaginary part, have. The various embodiments of the present invention may further include a battery integrity state determiner coupled to the battery internal impedance calculator and the battery health state determiner may estimate the current battery health state using the correlation between the impedance and the health state, And / or may determine.

A low-cost impedance spectroscopy method capable of estimating the sound state of a high-voltage battery pack according to various embodiments of the present invention includes: applying a perturbation current to a battery pack; Measuring a response voltage of the battery pack; A perturbation signal separating step of removing a direct current component from the voltage signal of the battery pack and isolating and outputting only an AC component; And an analog-to-digital converting step of converting an analog signal of the AC component by the perturbation signal separating step into a digital signal and outputting the digital signal.

The step of measuring the response voltage of the battery pack may be performed through a voltage-dividing resistor, and the step of dividing the perturbation signal may include a low-pass filter connected to the voltage-dividing resistor, and a differential amplifier circuit connected to the voltage-dividing resistor and the low- . The node of the voltage-dividing resistor may be connected to the inverting terminal of the differential amplifying circuit through the low-pass filter, and the node of the voltage-dividing resistor may be connected to the non-inverting terminal of the low-pass filter. And an AC signal and a DC signal can be output through the node of the voltage-dividing resistor, and only a DC signal can be output through the low-pass filter and input to an inverting terminal of the differential amplifier circuit, A signal and a DC signal can be input to the non-inverting terminal of the differential amplifying circuit. The differential amplifier circuit can output only the AC signal to the analog-to-digital converter.

The various embodiments of the present invention may separate the real and imaginary components of the voltage and current from the digital signal for the AC component after the analog to digital conversion step. Various embodiments of the present invention can calculate an impedance real part, an imaginary part, a magnitude, and a phase information indicating the battery internal impedance from the real and imaginary components of the voltage and current, respectively. Various embodiments of the present invention may estimate and / or determine the current battery health state using the correlation between the impedance and the health state.

Various embodiments of the present invention provide a low cost impedance spectroscopy system and method capable of estimating the sound state of a high voltage battery pack. That is, various embodiments of the present invention provide a method for detecting only an AC component in a battery voltage or current signal and measuring an impedance required for estimating the health state of the high-voltage battery pack.

In this way, when measuring the impedance of the high-voltage battery pack according to the related art, it is necessary to use an expensive high-performance analog-to-digital converter. However, by applying the technology according to the embodiment of the present invention, Impedance measurement is possible. In addition, the microprocessor's built-in analog-to-digital converter, which is generally used, has a majority of 12 bits, so it is possible to measure the impedance of a high-voltage battery pack without the need of installing an external analog-to-digital converter. This also improves product reliability due to economical efficiency, ease of implementation, precision and noise reduction. Also, when the technique according to the embodiment of the present invention is applied to a field other than the high voltage battery pack, the measurement accuracy can be maximized compared to the prior art.

Figs. 1 and 2 are diagrams for explaining the prior art.
FIG. 3 is a block diagram illustrating a low-cost impedance spectroscopy system capable of estimating the sound state of a high-voltage battery pack according to various embodiments of the present invention.
4 is a block diagram showing a general system of a voltage measuring unit for measuring voltage of a battery pack.
5 is a detailed circuit diagram of a general prior art.
6 is a block diagram showing the configuration of a voltage measuring unit for measuring a voltage of a high-voltage battery pack according to various embodiments of the present invention.
7 is a detailed circuit diagram according to various embodiments of the present invention.
8 is a PSIM simulation diagram for effect verification according to various embodiments of the present invention.
Figure 9 is a simplified equivalent battery model for simulation.
10 is a waveform diagram of a comparison result according to the prior art and the embodiment of the present invention.

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

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the drawings, like reference numerals refer to like elements, and as used herein, the term "and / or" includes any and all combinations of any of the listed items. The term " connected (or coupled) "in this specification means not only a case where the A member and the B member are directly connected (or coupled), but also a case where a C member is interposed between the A member and the B member This also means that the A member and the B member are indirectly connected (or connected, connected).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise, " and / or "comprising, " when used in this specification, are intended to be interchangeable with the said forms, numbers, steps, operations, elements, elements and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers and / or portions, these members, components, regions, layers and / It is obvious that no. These terms are only used to distinguish one member, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Also, in this specification, for example, the electrochemical characteristics that occur at the time of charging and discharging of a battery can be described by an impedance model. Since this impedance reflects the internal state of the battery, .

In addition, the impedance spectroscopy system and method described herein may be applied to a system for measuring a frequency-dependent impedance from a response to an applied perturbation (voltage or current) by applying a small perturbation (current or voltage) .

The state of health described herein is abbreviated as SOH (State of Health), which indicates a relative change with respect to the initial shipment of the battery. In general, the initial shipment state is indicated as 100%, and as the battery deteriorates The value decreases.

Further, a controller (microprocessor or controller) and / or other associated instrumentation or components in accordance with various embodiments of the present invention may be implemented in any suitable hardware, firmware (e.g., on-demand semiconductor), software, May be implemented using appropriate combinations. For example, the various components of a controller (controller) and / or other associated equipment or components in accordance with the present invention may be formed on one integrated circuit chip or on a separate integrated circuit chip. In addition, the various components of the controller (controller) may be implemented on a flexible printed circuit film and formed on the same substrate as the tape carrier package, printed circuit board, or controller (controller). In addition, the various components of the controller (controller) may be a process or thread executing on one or more processors in one or more computing devices, which executes computer program instructions to perform various functions, And interact with other components. The computer program instructions are stored in a memory that can be executed on a computing device using standard memory devices, such as, for example, random access memory. The computer program instructions may also be stored in other non-transitory computer readable media, such as, for example, CD-ROMs, flash drives, and the like. Further, those skilled in the art will appreciate that the functions of the various computing devices may be combined with one another, integrated into one computing device, or the functionality of a particular computing device may be implemented within one or more other computing devices Lt; / RTI > can be dispersed in the < / RTI >

For example, the controller according to the present invention may be implemented as a central processing unit, a mass storage device such as a hard disk or solid state disk, a volatile memory device, an input device such as a keyboard or a mouse, an output device such as a monitor or a printer, Of commercial computers.

Referring to FIG. 3, a block diagram of a low-cost impedance spectroscopy system 100 capable of estimating the sound state of a high-voltage battery pack according to various embodiments of the present invention is shown.

3, the impedance spectroscopy system 100 according to various embodiments of the present invention includes a hardware unit 110 and a software unit 120 including a microprocessor electrically connected to the hardware unit 110 Lt; / RTI > Substantially, a microprocessor drives software for implementing embodiments of the present invention.

Here, the hardware unit 110 may include a battery 111 and a power amplifier 112 electrically connected to the battery 111. The hardware unit 110 may further include a current measuring unit 113 and a voltage measuring unit 114 electrically connected between the battery 111 and the power amplifier 112.

The software section 120 also includes a digital to analog converter 121 and an analog to digital converter 122 and a digital to analogue converter 121 and a digital to analogue converter 121, A digital lock-in amplifier 123, a battery internal impedance calculator 124 that receives data from the digital lock-in amplifier 123, and a battery health state determiner 125 that receives data from the battery internal impedance calculator 124 do.

Here, the power amplifier 112 is controlled by a digital-to-analog converter 121 that receives data from the digital lock-in amplifier 123. The current signal and the voltage signal measured by the current measuring unit 113 and the voltage measuring unit 114 are transmitted to the digital lock-in amplifier 123 through the A / D converter 122.

The overall operation of the impedance spectroscopy system 100 will be described.

The software section 120 (microprocessor) controls the power amplifier 112 of the hardware section 110 to measure the internal impedance of the battery 111 in order to estimate the sound state of the battery 111 So that a frequency-dependent perturbation current is applied to the battery 111. That is, when the digital lock-in amplifier 123 outputs predetermined data to the digital / analog converter 121, the power amplifier 112 operates according to the analog output signal from the digital / analog converter 121, ) Is applied to the frequency-dependent perturbation current.

The voltage measuring unit 114 of the hardware unit 110 measures the response signal of the voltage of the battery 111 to the applied current as described above and outputs the response signal to the analog / digital converter 122 of the software unit 120, Lt; / RTI >

At this time, the current measuring unit 113 also measures the response signal of the current of the battery 111 and sends it to the analog-to-digital converter 122 of the software unit 120.

In this way, the software unit 120 converts the voltage and current into a digital value through the analog-to-digital converter 122 and then accurately measures only the signal of the desired frequency band from the noise in the digital lock-in amplifier 123, Separate each _real number (V _real , I _real ) and imaginary (V _img , I _img ) components.

The battery internal impedance calculator 124 calculates the real part Z _real and the imaginary part Z _img , the magnitude Z _mag and the phase Z _phase of the impedance representing the internal impedance of the battery 111 .

The battery health state determination unit 125 estimates and / or determines the current state of the battery 111 using the correlation between the internal impedance of the battery 111 and the health state SOH. Here, it is a matter of course that the relation between the internal impedance of the battery 111 and the sound condition is pre-stored in the memory in the form of a look-up table or a mathematical expression.

Referring to FIG. 4, there is shown a block diagram of a general system of a voltage measurement unit for measuring the voltage of a battery pack, and with reference to FIG. 5, a general prior art detailed circuit diagram is shown.

In order to measure the voltage with the microprocessor of the software section, the voltage signal of the battery must be converted according to the input voltage range of the analog / digital converter. In the conventional technology, as shown in FIGS. 4 and 5, The voltage was linearly reduced and input to the analog-to-digital converter. Here, separate circuits such as a differential amplifying circuit (for example, OP-amp) and a photocoupler can be used in an actual circuit configuration, but they are not included in this drawing.

Although the perturbation voltage to be measured is as small as several tens to several hundreds of mV, since the battery voltage does not exceed several tens of volts in the case of the conventional technology, the resolution is not a serious problem in the impedance measurement.

However, recently developed battery packs such as hybrid (HEV), electric vehicle (BEV) or energy storage system (ESS) use a high voltage band from about 330 V to 800 V, Impedance measurement is possible only by using a high-specification analog-to-digital converter that can not measure the small fluctuation voltage due to the resolution problem.

These high-end analog-to-digital converters are not only expensive, but also require an analog-to-digital converter installed outside the microprocessor in addition to the analog-to-digital converters mounted on existing microprocessors, And many other disadvantages.

Referring to FIG. 6, there is shown a block diagram of a voltage measuring unit for measuring voltage of a high-voltage battery pack according to various embodiments of the present invention. Referring to FIG. 7, detailed circuit diagrams according to various embodiments of the present invention Respectively.

The low-cost impedance spectroscopic system 100 and its method according to various embodiments of the present invention detect only the AC component to be measured due to the characteristics of the lock-in amplifier 123 electrically connected to the rear end of the A / D converter 122 And unnecessary direct current components that degrade the resolution are separated by the voltage measuring unit 114 and the perturbation signal separating unit 127.

6, the low-cost impedance spectroscopy system 100 according to various embodiments of the present invention is electrically connected to the battery 111 and is connected to the battery 111 through the power amplifier 112 A voltage measuring unit 114 for measuring a response voltage of the battery 111 in response to a fluctuation current of the battery 111 and a voltage measuring unit 114 for removing a direct current component from a voltage signal of the battery 111, And an analog / digital converter 122 for converting an analog signal corresponding to an AC component by the perturbation signal separator 127 into a digital signal and outputting the digital signal.

The low-cost impedance spectroscopy system 100 according to various embodiments of the present invention is characterized in that the voltage measuring unit 114 includes voltage dividing resistors R1 and R2 as shown in FIG. 7, and the perturbation signal separating unit A low pass filter 128 connected to the voltage dividing resistors R1 and R2 and a differential amplifier circuit 127a connected to the voltage dividing resistors R1 and R2 and the low pass filter 128. Herein, the voltage dividing resistors R1 and R2 include a first resistor R1 and a second resistor R2 connected in series, a first resistor R1 is connected to one end of the battery 111, The node R2 is connected to the other end (or the ground terminal) of the battery 111 and the node N is formed between the first resistor R1 and the second resistor R2.

The node N of the voltage-dividing resistors R1 and R2 is electrically connected to the inverting terminal (-) of the differential amplifying circuit 127a via the low-pass filter 128, (N) is also electrically connected to the non-inverting terminal (+) of the low-pass filter 128.

Here, the third resistor R3 is electrically connected between the low-pass filter 128 and the inverting terminal (-), and between the node N and the non-inverting terminal (+) of the voltage-dividing resistors R1 and R2 The fourth resistor R4 and the non-inverting terminal + are electrically connected to the ground terminal through the fifth resistor R5. Furthermore, a sixth resistor R6 is electrically connected between the inverting terminal (-) of the differential amplifying circuit 127a and the output terminal 127b.

When the AC signal and the DC signal of the battery 111 are output through the node N of the voltage-dividing resistors R1 and R2 in this way, only the DC signal is output through the low-pass filter 128, And the AC signal and the DC signal are inputted to the non-inverting terminal (+) of the differential amplifying circuit 127a through the node N of the voltage dividing resistors R1 and R2.

Therefore, the output terminal 127b of the differential amplifying circuit 127a outputs only the AC signal to the A / D converter 122. [

That is, in various embodiments of the present invention, only the DC component is extracted using the low-pass filter 128 and the DC component is removed using the differential amplification circuit 127a, And extracts only the component (perturbation signal) and transmits it to the A / D converter 122.

Thus, in various embodiments of the present invention, the impedance measurement of the high-voltage battery 111 becomes possible by using only a low-cost low-bit analog-to-digital converter 122. At this time, since the input maximum value of the OP-amp used in the differential amplifying circuit 127a is limited, a minimum voltage distributor 126 is required at the front end.

Referring to FIG. 8, there is shown a PSIM simulation diagram for effect verification in accordance with various embodiments of the present invention, and with reference to FIG. 9, a simplified equivalent battery model for simulation is shown, , A waveform diagram of a comparison result according to the prior art and the embodiment of the present invention is shown.

In Fig. 9, the battery is made to include only one resistor for a clear comparison with the prior art. Also, the open circuit voltage OCV of the battery 111 is set to 333 V, the internal resistance of the battery 111 is set to 45 mΩ, and the use of the 12-bit analog-to-digital converter 122 is assumed.

The simulation compares the impedance measured by the conventional method for measuring the internal impedance of the high voltage battery 111 and the impedance measured by the method according to various embodiments of the present invention.

As shown in FIG. 10, it can be seen that the waveforms of the prior art and various embodiments of the present invention are the same as those of the upper battery voltage. That is, the simulation is performed under the same conditions.

In the center of FIG. 10, the voltage input to the analog-to-digital converter 122 is compared. In the prior art, since the voltage divider reduces the voltage divider 140 times in order to match the input range, the perturbation signal band is 1.93 mV Small can be seen. Therefore, high-resolution analog-to-digital converters are required to detect this.

In the various embodiments of the present invention, since the perturbation signal band is 67.50 mV, which is more than 30 times larger than that of the conventional art, it is possible to measure with the low-end analog-to-digital converter 122.

Also, as can be seen in the bottom view of Fig. 10, in measuring the internal resistance of the battery of 45 m, the prior art measures 55.81 m [Omega] and the error is large, while the various embodiments of the present invention measure 44.94 m [ And the value is close to the value. Thus, it can be seen that the internal resistance of the battery is more accurately measured in various embodiments of the present invention.

Table 1 below summarizes simulation setting values and internal resistance measurement results. In the prior art, a low-cost 12-bit analog-to-digital converter built in a microprocessor is applied to various embodiments of the present invention rather than an expensive 16-bit analog-to-digital converter installed outside the microprocessor It is confirmed that the internal resistance can be measured precisely.

Classification Conventional technique Invention-based method simulation
Setting value Battery Open Circuit Voltage (OCV) [V] 333 Battery perturbation current [A] 3 ADC input range [V] 5 Perturbation frequency [Hz] 1000 Voltage share 1/140 1/4 Battery internal resistance [mΩ] 45 simulation
result 12-bit ADC measurement result [mΩ] 55.81 44.94 12-bit ADC measurement error rate [%] 24.02 0.13 16-bit ADC measurement result [mΩ] 44.77 44.98 16-bit ADC measurement error rate [%] 0.52 0.05

In this way, when measuring the impedance of a high-voltage battery pack according to the related art, it is necessary to use a high-cost high-performance analog-to-digital converter. However, the impedance measurement of the battery pack can be performed using only a low-cost analog- . In addition, the microprocessor's built-in analog-to-digital converter, which is generally used, has a large number of 12 bits. This improves product reliability due to economical efficiency, ease of implementation, precision and noise reduction. Also, when various embodiments of the present invention are applied to fields other than the high voltage battery pack, the measurement accuracy can be maximized compared with the prior art.

The present invention is not limited to the above-described embodiment, but may be applied to the following embodiments of the present invention. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

100; Impedance spectroscopy system
110; Hardware section 111; battery
112; Power amplifier 113; The current measuring unit
114; A voltage measuring unit 120; Software department (microprocessor)
121; Digital / analog converter 122; Analog-to-digital converter
123; Digital lock-in amplifier 124; Battery internal impedance calculation unit
125; The battery health state judging unit
126; A voltage divider 127; The perturbation signal separator
128; Low-pass filter

Claims (16)

Battery pack;
A power amplifier for applying a perturbation current to the battery pack;
A voltage measuring unit for measuring a response voltage of the battery pack;
A perturbation signal separator which removes a direct current component from the voltage signal of the battery pack by the voltage measuring unit and separates and outputs only an AC component; And
And an analog-to-digital converter for converting an analog signal of the AC component of the perturbation signal separator into a digital signal and outputting the digital signal, and outputting the digital signal. The method according to claim 1,
Wherein the voltage measuring unit includes a voltage dividing resistor,
Wherein the perturbation signal separator comprises a low pass filter connected to the voltage dividing resistor and a differential amplifier circuit connected to the voltage dividing resistor and the low pass filter. 3. The method of claim 2,
The node of the voltage-dividing resistor is connected to the inverting terminal of the differential amplifying circuit through the low-pass filter,
And a node of the voltage-dividing resistor is connected to a non-inverting terminal of the low-pass filter. A low-cost impedance spectroscopy system capable of estimating the sound state of a high-voltage battery pack. The method of claim 3,
An AC signal and a DC signal are output through a node of the voltage dividing resistor,
Only the DC signal is output through the low-pass filter and input to the inverting terminal of the differential amplifying circuit,
And an AC signal and a DC signal are input to a non-inverting terminal of the differential amplification circuit through a node of the voltage-dividing resistor. 5. The method of claim 4,
Wherein the differential amplifier circuit outputs only an AC signal to the analog-to-digital converter. 2. A low-cost impedance spectroscopy system capable of estimating a sound state of a high-voltage battery pack. The method according to claim 1,
Further comprising a digital lock-in amplifier connected to said analog to digital converter,
Wherein the digital lock-in amplifier separates real and imaginary components of voltage and current, respectively, and outputs the separated real and imaginary components, and outputs a low-impedance spectrum spectroscopy system capable of estimating the sound state of the high-voltage battery pack. The method according to claim 6,
Further comprising a battery internal impedance calculator connected to the digital lock-in amplifier,
Wherein the battery internal impedance arithmetic unit calculates an impedance real part, an imaginary part, a magnitude and a phase information indicating an internal impedance of the battery, and the inexpensive impedance spectral system capable of estimating the sound state of the high voltage battery pack. 8. The method of claim 7,
And a battery health state determiner coupled to the battery internal impedance calculator,
Wherein the battery health state determiner estimates a current battery health state using a correlation between the impedance and the health state, wherein the battery health state estimator estimates a current state of the battery. Applying a perturbation current to the battery pack;
Measuring a response voltage of the battery pack;
A perturbation signal separating step of removing a direct current component from the voltage signal of the battery pack and isolating and outputting only an AC component; And
And converting the analog signal of the alternating current component by the perturbation signal separating step into a digital signal and outputting the converted analog signal to the digital signal converting step. 10. The method of claim 9,
Wherein the step of measuring the response voltage of the battery pack is performed through a voltage-dividing resistor,
Wherein the step of separating the perturbation signal comprises a low pass filter connected to the voltage dividing resistor and a differential amplifying circuit connected to the voltage dividing resistor and the low pass filter. 11. The method of claim 10,
The node of the voltage-dividing resistor is connected to the inverting terminal of the differential amplifying circuit through the low-pass filter,
And a node of the voltage-dividing resistor is connected to a non-inverting terminal of the low-pass filter. 12. The method of claim 11,
An AC signal and a DC signal are output through a node of the voltage dividing resistor,
Only the DC signal is output through the low-pass filter and input to the inverting terminal of the differential amplifying circuit,
And the AC signal and the DC signal are input to the non-inverting terminal of the differential amplification circuit through the node of the voltage-dividing resistor, so as to estimate the sound state of the high-voltage battery pack. 13. The method of claim 12,
Wherein the differential amplifier circuit outputs only the AC signal to the analog-to-digital converter. 10. The method of claim 9,
And outputting the real and imaginary components of the voltage and current from the digital signal for the AC component after the analog to digital conversion step. 15. The method of claim 14,
And calculating an impedance real part, an imaginary part, a magnitude and a phase information indicating an internal impedance of the battery from the real and imaginary components of the voltages and currents, respectively, and estimating the sound state of the high voltage battery pack. 16. The method of claim 15,
And estimating a current state of the battery using a correlation between the impedance and the sound state. The low-cost impedance spectroscopy method according to claim 1,

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