KR20220097151A - Portable impedance spectroscopy instrument and method for measurement of impedance spectrum of high voltage battery pack - Google Patents

Abstract

A portable impedance spectroscopy instrument for measuring an impedance spectrum of a high voltage battery pack comprises: an initialization unit initializing a DAC unit and ADC unit when a command is delivered through a provided GUI; a DAC unit generating sine wave perturbation signals according to frequencies different from each other according to set perturbation amplitudes; an ADC unit acquiring a voltage and current waveform generated by the sine wave perturbation signals; and an impedance measurement unit deriving impedance at a certain frequency based on the acquired voltage and current waveform. Accordingly, the present invention may provide a portable EIS device capable of measuring an impedance spectrum of a high voltage battery pack without a separate external power supply.

Description

PORTABLE IMPEDANCE SPECTROSCOPY INSTRUMENT AND METHOD FOR MEASUREMENT OF IMPEDANCE SPECTRUM OF HIGH VOLTAGE BATTERY PACK

The present invention relates to a portable impedance spectrometer and method for measuring the impedance spectrum of a high voltage battery pack, and more particularly, to an inexpensive portable EIS (Electrochemical Impedance Spectroscopy) capable of measuring the impedance spectrum of a lithium ion battery pack without an external power supply. It's about the device.

Lithium-ion (Li-ion) batteries are widely used in large energy storage systems (ESS), such as energy storage power plants and electric vehicles (EVs), due to their advantages of high energy, high power, long cycle life, and high charging and discharging efficiency. widely used in In addition, with the recent rapid expansion of the electric vehicle market, batteries as a key component of electric vehicles are receiving more attention.

Battery performance directly affects the safety and reliability of EVs, so management skills are very important. Among them, a method of estimating the state of health (SOH) of a battery and predicting the remaining useful life (RUL) has become the focus, which is essential to ensure reliability and optimal performance over time.

In most literature related to electric mobility, the end of life (EOL) of an EV battery is defined as a 20% reduction in cell capacity from a nominal value. However, it can still store large amounts of energy and work in another application, more recently called secondary life batteries (SLBs).

By collecting used batteries from EVs and examining the SOH of the battery packs to estimate the remaining capacity, the batteries can be useful in secondary life applications when: If the SOH of the battery is greater than 40%, it can be recycled for re-use. It can be divided into modules or cells to create new systems for SLB applications. SLB modules or cells can be reconnected in series or parallel to obtain the energy and power required for a particular application. After the secondary life, the battery is recycled to recover the raw material.

To estimate the SOH of a battery, EIS is one of the diagnostic techniques with advantages of convenience, speed and accuracy. EIS is a non-destructive technology that provides a significant amount of information in a relatively short period of time. In addition, EIS technology can be used in a variety of applications such as quality assurance in production lines, battery health estimation including state of charge (SOC), SOH, internal temperature monitoring and RUL estimation.

There are many advantages to using EIS to understand the power delivery capability of a lithium-ion battery system. It is a useful tool used in a variety of fields including applied chemistry, biomedical science, physical cells, and many other fields of engineering. In addition, power sources such as fuel cells, supercapacitors and batteries can be modeled and diagnosed as useful tools.

However, there are few portable commercial EIS equipment developed so far, and stationary equipment requiring an external power source is quite expensive and has a problem in that it is mainly designed to measure the impedance of low-voltage equipment.

KR 10-2013-0083220 A KR 10-2016-0103332 A KR 10-1429292 B1

Accordingly, it is an object of the present invention to provide a portable impedance spectrometer for measuring an impedance spectrum of a high voltage battery pack.

Another object of the present invention is to provide a method for measuring an impedance spectrum of a high voltage battery pack using the portable impedance spectrometer.

A portable impedance spectrometer for measuring an impedance spectrum of a high voltage battery pack according to an embodiment for realizing the object of the present invention includes: an initialization unit that initializes a DAC unit and an ADC unit when a command is transmitted through a provided GUI; a DAC unit for generating a sinusoidal perturbation signal according to different frequencies according to the set perturbation amplitude; ADC unit for acquiring voltage and current waveforms generated by the perturbation signal; and an impedance measuring unit deriving an impedance at a specific frequency based on the obtained voltage and current waveforms.

In an embodiment of the present invention, the DAC unit may generate two sinusoidal sweep reference signals superimposed on the DC signal.

In an embodiment of the present invention, the DAC unit may include a control logic including a switch, a comparator, a current sensor, and an amplifier to control the perturbation signal.

In an embodiment of the present invention, the DAC unit may control the perturbation signal by comparing the gate voltage of the switch with the generated sinusoidal sweep reference signal through the feedback of the current sensor.

In an embodiment of the present invention, the ADC unit may include a passive high-pass filter, an active low-pass filter, and an operational amplifier.

In an embodiment of the present invention, the portable impedance spectrometer may be connected to an external device through a USB port.

In an embodiment of the present invention, the portable impedance spectrometer may transmit the calculated impedance result to an external device so that the external device can display the impedance of a specific frequency in real time.

In an embodiment of the present invention, the portable impedance spectrometer may further include at least one of a microcontroller, a high voltage protection circuit, a signal conditioning circuit, and a sensing circuit.

In the method for measuring the impedance spectrum of a high voltage battery pack using a portable impedance spectrometer according to an embodiment for realizing another object of the present invention, when a command is transmitted to a portable impedance spectrometer connected to the battery pack, the DAC unit and the ADC unit are initialized to do; generating a sinusoidal perturbation signal according to different frequencies according to the perturbation amplitude set through the DAC unit; acquiring voltage and current waveforms generated by the perturbation signal through the ADC unit; and deriving an impedance at a specific frequency based on the obtained voltage and current waveforms.

In an embodiment of the present invention, the generating of the sinusoidal wave perturbation signal may include comparing the gate voltage of the switch with the generated sinusoidal sweep reference signal through feedback of the current sensor to control the perturbation signal.

In an embodiment of the present invention, the method for measuring the impedance spectrum of the high voltage battery pack may further include transmitting the calculated impedance result to an external device so that the external device can display the impedance of a specific frequency in real time. .

According to such a portable impedance spectrometer for measuring the impedance spectrum of a high voltage battery pack, it is possible to provide a low-cost portable EIS device capable of measuring the impedance spectrum of a lithium ion battery pack up to 1000 V without a separate external power supply.

Existing commercial devices require external power to generate a sinusoidal perturbation current, but the EIS device proposed in the present invention does not require external power because the impedance spectrum of the battery is measured only during discharge. In addition, the EIS device proposed in the present invention has the advantage that only a small amount of power is required for the operation of the circuit that can be supplied through the USB cable.

1 is a block diagram of a portable impedance spectrometer for measuring an impedance spectrum of a high voltage battery pack according to an embodiment of the present invention.
2 is a diagram showing an example of an equivalent circuit model (ECM) of a battery.
FIG. 3 is a diagram for showing chemical reactions related to different frequency domains of the Nyquist plot of the battery of FIG. 2 .
FIG. 4 is an exemplary block diagram of an EIS system including the portable impedance spectrometer of FIG. 1 ;
5 is an exemplary diagram of a high-precision current sink that can be used to control the perturbation current in the present invention.
6 is a diagram showing an example of connecting to an EIS device of the present invention using a Kelvin line connection.
7 is a diagram showing an example of the DLA-based EIS algorithm of the MCU used in the present invention and the LabVIEW software-based GUI.
8 is an exemplary block diagram of a DLA for calculating an impedance in the present invention.
9 and 10 are graphs showing impedance measurement spectra of the EIS device of the present invention and the commercial EIS device.
11 is a flowchart of a method for measuring an impedance spectrum of a high voltage battery pack using the portable impedance of FIG. 1 according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein with respect to one embodiment may be implemented in other embodiments without departing from the spirit and scope of the invention. In addition, it should 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 following detailed description 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 scope equivalents to those claimed. Like reference numerals in the drawings refer to the same or similar functions throughout the various aspects.

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

1 is a block diagram of a portable impedance spectrometer for measuring an impedance spectrum of a high voltage battery pack according to an embodiment of the present invention.

The portable impedance spectrometer (10, hereinafter EIS device) for measuring the impedance spectrum of a high voltage battery pack according to the present invention is a battery state such as SOH (State of Health) and RUL (Remaining Useful Life) of the battery. It is a portable device that can measure the impedance spectrum of a high-voltage battery pack without an external power supply for diagnosing it.

Referring to FIG. 1 , an EIS device 10 according to the present invention includes an initialization unit 110 , a DAC unit 130 , an ADC unit 150 , and an impedance measuring unit 170 .

In the EIS device 10 of the present invention, software (application) for performing impedance spectrum measurement of a high voltage battery pack may be installed and executed, and the initialization unit 110, the DAC unit 130, and the ADC unit ( 150) and the configuration of the impedance measuring unit 170 may be controlled by software for measuring the impedance spectrum of the high voltage battery pack executed in the EIS device 10 .

The EIS device 10 may be a separate terminal or a part of a module of the terminal. In addition, the initialization unit 110 , the DAC unit 130 , the ADC unit 150 , and the impedance measuring unit 170 may be configured as an integrated module or one or more modules. However, on the contrary, each configuration may be formed of a separate module.

The EIS device 10 is a portable device having mobility. The EIS device 10 includes other devices such as a device, an application, a terminal, a user equipment (UE), a mobile station (MS), a wireless device, and a handheld device. can be termed as

The EIS device 10 may execute or manufacture various software based on an operating system (OS), that is, the system. The operating system is a system program for software to use the hardware of the device, and may include all mobile computer operating systems such as Android OS, iOS, Windows Mobile OS, Bada OS, Symbian OS, and BlackBerry OS.

The State of Health (SOH) of a battery represents the Remaining Useful Life (RUL) of the battery, and thus is an important parameter in the battery usage process.

Meanwhile, Electrochemical Impedance Spectroscopy (EIS) is a technique widely used to observe the state of a battery. The impedance measured at a specific frequency is closely related to the underlying chemical reaction and can therefore be used to evaluate battery health.

To this end, the present invention provides a low-cost portable EIS device 10 based on a microcontroller device (eg, ARM Cortex-M4 MCU) to measure the impedance spectrum of a lithium ion battery pack.

The MCU uses a built-in DAC module to generate a sinusoidal sweep perturbation signal. In addition, it is possible to perform dual channel acquisition of voltage and current signals, calculate the impedance using a digital lock-in amplifier (DLA), and transmit the result to an external device such as a PC.

In one embodiment, an interface is provided for displaying EIS information in real time using LabVIEW. The EIS device 10 proposed in the present invention is suitable for measuring the impedance spectrum of the battery pack up to 1000V. The measurement frequency range of the EIS device 10 was designed to be 1 Hz to 1 Khz. In addition, to prove the performance of the developed device, the impedances of the Samsung SM3 battery pack and the Bexel pouch module were measured and compared with those obtained from commercial devices.

When a command is transmitted through the GUI provided, the EIS device 10 initializes the DAC unit 130 and the ADC unit 150 through the initialization unit 110, and a sine wave of small amplitude at different frequencies. Measure the impedance spectrum of the battery with the perturbation signal.

This provides useful information about the internal electrochemical processes inside the battery and can be used to extract the parameters of the equivalent circuit model (ECM) of the battery in the future. In addition, useful information about the aging, condition and capacity of the battery can be used to manage the battery for better performance and longer life cycle.

The DAC unit 130 generates a sinusoidal perturbation signal according to different frequencies according to the set perturbation amplitude.

An example of an equivalent circuit model (ECM) of a battery is shown in FIG. 2 . The chemical reactions involved in different frequency domains of the Nyquist plot are shown in FIG. 3 .

The high-frequency EIS is a straight line that reflects the inductive components of the battery and measuring device. The intersection of the horizontal axis represents the resistive impedance (R _s ) corresponding to the resistance of the electrolyte, electrode, and wire used in the test. The aging of lithium-ion batteries is caused by a combination of various phenomena. Formation of microcracks, gas generation, binder decomposition, current collector corrosion, and electrolyte depletion are all reported as causes of battery aging and performance degradation.

Therefore, it is difficult to distinguish these different processes and to identify the characteristics of aging. In many cases, measuring R _s using EIS is a useful way to evaluate the aging of a battery. In the Nyquist plot, the arc in the intermediate frequency region is caused by the charge transfer resistance of Li ⁺ at the interface between the electrode and the electrolyte, and as shown in Equation 1 below, the charge transfer internal resistance (R _ct ) and the equivalent factor (Constant phase element; Z _CPE ) is represented as a parallel circuit.

[Equation 1]

where Q is a time constant and n is a real number between 0 and 1. R _ct has the largest value in the total cell resistance at room temperature, and the power density of lithium-ion batteries mainly depends on R _ct . The low-frequency region is interpreted as a solid diffusion impedance expressed by the Warburg impedance (Z _W ) given by Equation 2 below. where Q is the mass transfer coefficient.

[Equation 2]

There are various types of electrochemical analysis methods that can be used to investigate the internal processes of batteries. However, in the case of EIS analysis, important information can be obtained from each component of the equivalent circuit model of a battery cell in one experiment. In addition, it is a non-destructive method that does not damage the battery, and has the advantage that the time required to perform the measurement is relatively short.

Once the correct circuit model is established, the analysis can obtain the parameter values of each component in the ECM of the lithium-ion battery. Since the measurement is easy regardless of the size of the battery, the EIS device 10 proposed in the present invention can be an efficient analysis tool to investigate the degradation mechanism of the LIB.

FIG. 4 is an exemplary block diagram of an EIS system including the portable impedance spectrometer of FIG. 1 ;

In the system 1 of this embodiment, the EIS device 10 may be a plug-and-play device connected to an external device 3 such as a PC through a USB port. For example, the system 1 is controlled by LabVIEW.

The peripheral PCB board 5 may include an MCU, current control logic, high voltage protection, signal conditioning and sensing circuitry, and the like. To perturb the battery pack, for example, an MCU's 12-bit DAC is used to generate a sinusoidal sweep reference signal superimposed on the DC signal as shown in Equations 3 and 4 below.

[Equation 3]

[Equation 4]

The frequency range used in the present invention is 1 Hz to 1 kHz, with 6 and 3 frequencies per decade. The measured voltage and current signals can be collected from the battery pack by two separate 16-bit ADCs. For high accuracy of the acquired signal, a 200 kHz sampling frequency can be used.

A high-precision current sink can be used to control the perturbation current. The control logic may be composed of a switch, a comparator, a current sensor, and an amplifier as shown in FIG. 5 .

Referring to FIG. 5 , the gate voltage of the switch is controlled by receiving feedback from the current sensor and comparing it with the input reference signal (V _ref ) generated by the DAC. When a positive voltage is applied to V _ref , the output voltage of the comparator increases, turning on the switch and driving the current.

As the current rises, the voltage across the current sensor also rises and the voltage feedback to the comparator increases until V _ref . When the input signal of V _ref is sinusoidal, it generates a sinusoidal current through the switch. The gain of feedback reduces the sensitivity of the input reference signal.

The battery pack may be connected to the EIS device of the present invention using a Four-Wire Kelvin connection as shown in FIG. 6 . The Four-Wire connector can eliminate wire resistance, and this structure can improve the accuracy of the measurement.

The ADC unit 150 acquires voltage and current waveforms generated by the perturbation signal.

The voltage across the battery can be measured using a passive high-pass filter and an active low-pass filter used to block DC and allow the ADC to acquire only filtered AC. Also, the current may be sensed by a sense resistor and amplified through an operational amplifier.

The impedance measuring unit 170 measures the impedance at a specific frequency based on the obtained voltage and current waveforms. The impedance measuring unit 170 may extract only necessary frequency components from the acquired current and voltage data, and the impedance at a specific frequency may be calculated by DLA.

The software used in the present invention may be composed of the DLA-based EIS algorithm of the MCU and the LabVIEW software-based GUI as shown in FIG. 7 .

A graphical user interface (GUI) based on LabVIEW software is provided to display and evaluate battery pack impedance. Accordingly, due to the simplicity of the software, no complicated training is required before operators can perform measurements.

For example, when the run button is pressed, the system starts generating a sinusoidal sweep signal of the desired amplitude to perturb the battery pack, resulting in current and voltage waveforms collected by the MCU. A desired frequency component may be extracted through the DLA, and the impedance of the specific frequency may be displayed in real time through the external device 3 such as a PC.

The obtained signal is expressed by Equation 5 below.

[Equation 5]

Here, A is the amplitude of the measured signal, and Θ is the initial phase. The signal is discretized at the sampling frequency f _s = Nf. where f is the frequency of the measured signal and N is the number of samples. The sampling time interval is t _s = 1/(Nf). The two reference signals are expressed by Equations 6 and 7 below. Here, B is the amplitude of the reference signal.

[Equation 6]

[Equation 7]

If the measured signal is multiplied by two reference signals, that is, a difference frequency term (DC signal) and a sum frequency term (double the reference signal frequency), Equation 8 and Equation 8 below, respectively 9 is derived.

[Equation 8]

[Equation 9]

The two outputs are passed through the low-pass filter to derive two DC signals as shown in Equations 10 and 11 below, respectively.

[Equation 10]

[Equation 11]

The amplitude and phase of the acquired signal are obtained using Equations 12 and 13 below, respectively.

[Equation 12]

[Equation 13]

Two separate DLAs are used to obtain the amplitudes (A _v and A _I ) and phases (Θ _v and Θ _I ) of the acquired voltage and current signals. Impedance Z can be calculated using Equation 14 below. An example of a block diagram of a DLA for calculating impedance is shown in FIG. 8 .

[Equation 14]

Hereinafter, in order to verify the performance and accuracy of the EIS device 10 proposed in the present invention, the results of performing an experiment by measuring the impedance spectra of the Samsung SM3 ZE battery pack and the Bexel pouch module will be described.

The EIS device 10 of the present invention is respectively connected to a PC and a battery pack through a USB cable and a 4-wire Kelvin connection cable. Table 1 below shows the specifications of the battery pack and pouch module.

[Table 1]

Results are compared using commercially available instruments to verify the performance of the present invention. As shown in FIG. 9 , the impedance spectrum measured by the EIS device 10 of the present invention and the commercial device of the Samsung SM3 ZE battery pack agrees well with each other and shows a chi-square of 0.728%. 10 shows the result of the Bexel pouch module having a chi-square of 0.662%, through which the measurement accuracy of the EIS device 10 proposed in the present invention can be confirmed.

The present invention provides a low-cost portable EIS device capable of measuring the impedance spectrum of a lithium-ion battery pack up to 1000V without a separate external power supply.

Existing commercial devices require external power to generate a sinusoidal perturbation current, but the EIS device proposed in the present invention does not require external power because the impedance spectrum of the battery is measured only during discharge. In addition, the EIS device 10 proposed in the present invention has the advantage that only a small amount of power is required for the operation of the circuit that can be supplied through the USB cable.

11 is a flowchart of a method for measuring an impedance spectrum of a high voltage battery pack using the portable impedance of FIG. 1 according to an embodiment of the present invention.

The impedance spectrum measurement method of the high voltage battery pack using the portable impedance spectrometer according to the present embodiment may be performed using substantially the same configuration as the EIS device 10 of FIG. 1 .

Accordingly, the same components as those of the EIS device 10 of FIG. 1 are given the same reference numerals, and repeated descriptions are omitted. Also, the method for measuring the impedance spectrum of the high voltage battery pack using the portable impedance spectrometer according to the present embodiment may be executed by software (application) for performing the impedance spectrum measurement of the high voltage battery pack using the portable impedance spectrometer.

The present invention generates a sinusoidal swept perturbation signal using a low-cost portable EIS instrument for measuring the impedance spectrum of a lithium-ion battery pack. In addition, it is possible to perform dual channel acquisition of voltage and current signals, calculate the impedance using a digital lock-in amplifier (DLA), and transmit the result to an external device such as a PC.

Referring to FIG. 11 , in the method of measuring the impedance spectrum of a high voltage battery pack using a portable impedance spectrometer according to the present embodiment, when a command is transmitted to a portable impedance spectrometer connected to the battery pack, the DAC unit and the ADC unit are initialized (step S10). .

Commands may be provided through a graphical user interface (GUI) based on LabVIEW software, the GUI being provided to display and evaluate the battery pack impedance. Accordingly, due to the simplicity of the software, no complicated training is required before operators can perform measurements.

For example, when the run button is pressed, the system starts generating a sinusoidal sweep signal of the desired amplitude to perturb the battery pack, resulting in current and voltage waveforms collected by the MCU. A desired frequency component may be extracted through the DLA, and the impedance of the specific frequency may be displayed in real time through an external device such as a PC.

Thereafter, a sine wave perturbation signal according to different frequencies is generated according to the perturbation amplitude set through the DAC unit (step S30). In this case, the perturbation signal may be controlled by comparing the gate voltage of the switch with the generated sinusoidal sweep reference signal through the feedback of the current sensor.

The voltage and current waveforms generated by the perturbation signal are acquired through the ADC unit (step S50).

In this case, the voltage across the battery can be measured using a passive high-pass filter and an active low-pass filter used to block DC and allow the ADC to acquire only filtered AC. Also, the current may be sensed by a sense resistor and amplified through an operational amplifier.

An impedance at a specific frequency is derived based on the obtained voltage and current waveforms (step S70).

The measured impedance provides useful information about the internal electrochemical process inside the battery and can be used to extract the parameters of the equivalent circuit model (ECM) of the battery in the future. In addition, useful information about the aging, condition and capacity of the battery can be used to manage the battery for better performance and longer life cycle.

In addition, the calculated impedance result may be transmitted to the external device so that the impedance of a specific frequency can be displayed in real time.

Such a method of measuring the impedance spectrum of a high voltage battery pack using a portable impedance spectrometer may be implemented as an application or implemented in the form of program instructions that may 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 are specially designed and configured for the present invention, and may be known and available to those skilled in the computer software field.

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

Examples of program instructions include not only machine language codes such as those generated 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 for carrying out the processing according to the present invention, and vice versa.

Although the above has been described with reference to the embodiments, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand.

The present invention proposes a portable EIS device capable of measuring the impedance spectrum of a lithium ion battery pack. The measurable frequency range is designed to be 1Hz to 1kHz, and the EIS device of the present invention can measure the impedance spectrum of the battery pack up to 1000V. It can also be used to evaluate the RUL of an EV battery pack for reuse.

As a result of the experiment, it was verified that the EIS device of the present invention has excellent accuracy as a commercial device. The EIS device of the present invention uses only a 5V USB power supply and does not require a separate external power supply. The EIS device of the present invention may be in the form of a plug-and-play device, and is usefully used in applications for measuring the state of the battery, such as the state of health (SOH) and the remaining useful life (RUL) of the battery. can be

10: Handheld Impedance Spectrometer
110: initialization unit
130: DAC unit
150: ADC unit
170: impedance measuring unit
1: system
3: External device
5: Peripheral PCB board

Claims (11)

an initialization unit that initializes the DAC unit and the ADC unit when a command is transmitted through the provided GUI;
a DAC unit for generating a sinusoidal perturbation signal according to different frequencies according to the set perturbation amplitude;
ADC unit for acquiring voltage and current waveforms generated by the perturbation signal; and
an impedance measuring unit for deriving an impedance at a specific frequency based on the obtained voltage and current waveforms; A portable impedance spectrometer for measuring the impedance spectrum of a high voltage battery pack.
The method of claim 1, wherein the DAC unit,
Handheld impedance spectrometer for impedance spectral measurement of high voltage battery packs, generating two sinusoidal swept reference signals superimposed on a DC signal.
The method of claim 2, wherein the DAC unit,
A portable impedance spectrometer for impedance spectrum measurement of a high voltage battery pack comprising a control logic comprising a switch, a comparator, a current sensor and an amplifier to control the perturbation signal.
The method of claim 3, wherein the DAC unit,
Handheld impedance spectrometer for impedance spectrum measurement of high voltage battery packs, which controls the perturbation signal by comparing the gate voltage of the switch with a generated sinusoidal sweep reference signal via feedback from a current sensor.
According to claim 1, wherein the ADC unit,
Portable impedance spectrometer for impedance spectral measurement of high voltage battery packs, comprising a passive high-pass filter and an active low-pass filter and an operational amplifier.
According to claim 1,
Portable impedance spectrometer for impedance spectrum measurement of high voltage battery packs, connected to an external device via USB port.
7. The method of claim 6,
A portable impedance spectrometer for measuring the impedance spectrum of a high voltage battery pack that transmits the calculated impedance result to an external device so that the external device can display the impedance of a specific frequency in real time.
The method of claim 1,
A portable impedance spectrometer for measuring an impedance spectrum of a high voltage battery pack, further comprising at least one of a microcontroller, a high voltage protection circuit, a signal conditioning circuit and a sensing circuit.
Initializing the DAC unit and the ADC unit when a command is transmitted to the portable impedance spectrometer connected to the battery pack;
generating a sinusoidal perturbation signal according to different frequencies according to the perturbation amplitude set through the DAC unit;
acquiring voltage and current waveforms generated by the perturbation signal through the ADC unit; and
deriving an impedance at a specific frequency based on the obtained voltage and current waveforms; Including, a method for measuring an impedance spectrum of a high voltage battery pack.
The method of claim 9, wherein generating the sinusoidal perturbation signal comprises:
A method for measuring an impedance spectrum of a high-voltage battery pack, comprising controlling a perturbation signal by comparing a gate voltage of a switch with a generated sinusoidal sweep reference signal through feedback from a current sensor.
10. The method of claim 9,
Transmitting the calculated impedance result to an external device so that the impedance of a specific frequency can be displayed in real time from the external device; further comprising, a method of measuring an impedance spectrum of a high voltage battery pack.

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