WO2023249214A1

WO2023249214A1 - Impedance measuring device and operation method therefor

Info

Publication number: WO2023249214A1
Application number: PCT/KR2023/004479
Authority: WO
Inventors: 최연식
Original assignee: 주식회사 엘지에너지솔루션
Priority date: 2022-06-24
Filing date: 2023-04-03
Publication date: 2023-12-28
Also published as: KR20240000983A

Abstract

An impedance measuring device for measuring the impedance of a battery cell on the basis of a measured voltage, according to one embodiment of the present invention, may comprise: a precharge circuit for precharging the impedance measuring device; a detection unit for detecting the precharge voltage of the impedance measuring device; a processor for comparing the precharge voltage with a reference voltage; and a voltage generating unit for outputting the measured voltage.

Description

Impedance measuring device and method of operation thereof

Cross-citation with related applications

The present invention claims the benefit of priority based on Korean Patent Application No. 10-2022-0077856 filed on June 24, 2022, and all contents disclosed in the document of the Korean Patent Application are included as part of this specification.

Technology field

Embodiments disclosed in this document relate to an impedance measurement device and method of operating the same.

Recently, research and development on secondary batteries has been actively conducted. Secondary batteries are batteries that can be charged and discharged, and may include both conventional Ni/Cd batteries, Ni/MH batteries, and recent lithium-ion batteries. Lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni/Cd batteries, Ni/MH batteries, etc. In addition, lithium-ion batteries can be made small and lightweight, so they are used as a power source for mobile devices, and recently, they have been used as electric power sources. Its range of use as a power source for automobiles has expanded, and it is attracting attention as a next-generation energy storage medium.

Electrochemical Impedance Spectroscopy can be used to analyze the state of the battery and detect the operating characteristics of the battery over time. Electrochemical impedance spectroscopy can quickly and accurately detect impedance, a factor that interferes with electrical transmission when a chemical reaction occurs in the electrodes contained in the battery.

By detecting impedance, the state of the battery can be quickly evaluated, and based on the evaluation, the quality of the battery can be inspected, the remaining lifespan predicted, and the charging method optimized according to the battery state.

One purpose of the embodiments disclosed in this document is to provide an impedance measurement device and a method of operating the same that can effectively measure the impedance of a battery cell.

One purpose of the embodiments disclosed in this document is to provide an impedance measurement device including a precharge circuit to ensure the stability of the impedance measurement device and a method of operating the same.

One purpose of the embodiments disclosed in this document is to provide an impedance measurement device and a method of operating the same, including a detection unit that checks whether the pre-charge voltage of the impedance measurement device has reached the reference voltage.

The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

An impedance measurement device for measuring the impedance of a battery cell based on a measured voltage according to an embodiment of the present invention includes a precharge circuit for precharging the impedance measurement device, a detection unit for detecting a precharge voltage of the impedance measurement device, and the impedance measurement device. It may include a processor that compares the precharge voltage and a reference voltage, and a voltage generator that outputs the measured voltage.

According to one embodiment, the precharge circuit may precharge the impedance measurement device with a direct current voltage.

According to one embodiment, when the precharge voltage is greater than or equal to the reference voltage, the processor may control the precharge circuit to maintain the direct current voltage.

According to one embodiment, when the precharge voltage is less than the reference voltage, the processor may control the precharge circuit to increase the direct current voltage.

According to one embodiment, the detector may be an analog digital converter (ADC) that converts the precharge voltage into a digital code.

According to one embodiment, the measured voltage may be alternating current voltage.

According to one embodiment, when the precharge voltage is greater than or equal to the reference voltage, the processor may control the voltage generator to output the measured voltage.

According to one embodiment, when the precharge voltage is less than the reference voltage, the processor may control the voltage generator not to output the measured voltage.

According to one embodiment, the reference voltage may be determined based on the voltage of the battery cell and the circuit of the impedance measurement device.

According to one embodiment, the detector may detect the precharge voltage at a preset time period.

A method of operating an impedance measuring device that measures the impedance of a battery cell based on a measured voltage according to an embodiment of the present invention includes the steps of a precharge circuit precharging the impedance measuring device, and a detection unit measuring the precharge voltage of the impedance measuring device. It may include detecting and the processor comparing the precharge voltage and a reference voltage.

According to one embodiment, the step of comparing the precharge voltage and the reference voltage by the processor includes controlling a voltage generator to output a measured voltage when the precharge voltage is higher than the reference voltage, and If it is less than the reference voltage, it may include controlling the voltage generator not to output the measured voltage.

According to one embodiment, the step of precharging the impedance measurement device by the precharge circuit may be a step of precharging the impedance measurement device by the precharge circuit with a direct current voltage.

According to one embodiment, the step of comparing the precharge voltage and the reference voltage by the processor includes controlling the precharge circuit to maintain the direct current voltage when the precharge voltage is greater than or equal to the reference voltage, and When the voltage is less than the reference voltage, controlling the precharge circuit to increase the direct current voltage may be included.

According to one embodiment, detecting the precharge voltage may include converting the precharge voltage into a digital code by the detector and transmitting the digital code to the processor by the detector.

The impedance measuring device and its operating method according to an embodiment disclosed in this document can improve the operational stability of the impedance measuring device.

The impedance measurement device according to an embodiment disclosed in this document may include a detection unit, and the operation speed of the measurement device can be improved through the detection unit.

The impedance measuring device and its operating method according to an embodiment disclosed in this document can diagnose the state of a battery cell.

In addition, various effects that can be directly or indirectly identified through this document may be provided.

1 is a block diagram showing an impedance measurement device according to an embodiment disclosed in this document.

Figure 2 is for explaining the measurement voltage output time of the impedance measurement device according to an embodiment disclosed in this document.

Figure 3 is a flowchart showing a method of operating an impedance measurement device according to an embodiment disclosed in this document.

Figure 4 is a flowchart showing a method for outputting a measured voltage according to an embodiment disclosed in this document.

Figure 5 is a flowchart showing a method of operating an impedance measurement device according to another embodiment disclosed in this document.

Figure 6 is a flowchart showing a precharge voltage detection method according to another embodiment disclosed in this document.

Figure 7 is a block diagram showing the hardware configuration of a computing system for performing a method of operating an impedance measurement device according to an embodiment disclosed in this document.

Hereinafter, embodiments disclosed in this document will be described in detail through illustrative drawings. When adding reference numerals to components in each drawing, it should be noted that identical components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the embodiments disclosed in this document, if it is determined that detailed descriptions of related known configurations or functions impede understanding of the embodiments disclosed in this document, the detailed descriptions will be omitted.

In describing the components of the embodiment disclosed in this document, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. Additionally, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the embodiments disclosed in this document belong. . Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present application. No.

Referring to FIG. 1, the impedance measurement device 100 according to an embodiment disclosed in this document may be connected to the battery pack 200.

The impedance measurement device 100 may include a processor 110, a precharge circuit 120, a detector 130, and a voltage generator 140.

The impedance measurement device 100 may, for example, be an electrochemical impedance spectroscopy device. The electrochemical impedance spectroscopy device may be a device that measures the alternating current impedance spectrum of the battery cell 210 included in the battery pack 200 using a non-destructive inspection method.

According to an embodiment, the impedance measurement device 100 may estimate the deterioration state and performance of the battery cell 210 by comparing the measured alternating current impedance spectrum with an equivalent circuit model of the battery cell 210.

The impedance measurement device 100 measures the alternating current (AC) of the battery cell 210 based on the amplitude and phase change of the signal detected in the battery pack 200 as the frequency of the alternating current (AC) power applied to the battery pack 200 is changed. The impedance spectrum can be calculated.

Specifically, the impedance measurement device 100 applies an alternating voltage (measurement voltage) to the battery pack 200 to induce impedance perturbation in the battery cell 210, and generates a response to the induced perturbation (response to the impedance of the battery cell). The impedance of the battery cell 210 can be calculated based on the information). Impedance calculation of the battery cell 210 may be performed by the processor 110 included in the impedance measurement device 100.

The impedance measurement device 100 may obtain information about the state of the battery cell 210 by calculating parameters for the equivalent circuit of the battery cell 210 based on information about the impedance of the battery cell 210.

The impedance measurement device 100 may be precharged by the precharge circuit 120. The impedance measurement device 100 may be precharged to a reference voltage by the precharge circuit 120. As the impedance measurement device 100 is precharged to the reference voltage, the influence of the circuit structure of the impedance measurement device 100 and the influence of the voltage of the battery cell 210 can be reduced when measuring the impedance of the battery cell 210. You can. According to an embodiment, the reference voltage may be referred to as an offset voltage.

Specifically, when the impedance measurement device 100 is precharged with a reference voltage, the impedance perturbation of the battery cell 210 due to the measurement voltage output by the impedance measurement device 100 can be detected more sensitively.

The processor 110 controls signals applied to the impedance measurement device 100 and/or the battery pack 200 and performs calculations based on data received from the impedance measurement device 100 and/or the battery pack 200. It can be done. The processor 110 may, for example, be a microcontroller unit (MCU).

The processor 110 may control the precharge circuit 120 to precharge the impedance measurement device 100. Additionally, the processor 110 may control the state of the precharge circuit 120 and/or the voltage generator 140 by comparing the precharge voltage of the impedance measurement device 100 with the reference voltage.

If the precharge voltage is higher than the reference voltage, the processor 110 may control the direct current voltage output from the precharge circuit 120 to be maintained. Additionally, the processor 110 may control the direct current voltage output from the precharge circuit 120 to increase when the precharge voltage is less than the reference voltage.

According to an embodiment, the precharge voltage may be the voltage of the impedance measurement device 100 when it is in a precharge state. The direct current voltage output from the precharge circuit 120 during precharge may increase in voltage value over time. Additionally, when the precharge voltage is higher than the reference voltage, the precharge state may be terminated, and the precharge circuit 120 may output a direct current voltage of a certain magnitude.

The precharge voltage can be detected by the detection unit 130. The detection unit 130 may detect the voltage of the impedance measurement device 100. According to an embodiment, the detection unit 130 may detect the voltage of a power storage element included in the impedance measurement device 100 and detect the precharge voltage of the impedance measurement device 100 based on the detected voltage. The storage element may, for example, be a capacitor.

Depending on the embodiment, the detector 130 may be an analog digital converter (ADC) that converts the precharge voltage into a digital code. ADCs can have excellent dynamic range, speed, and resolution, and low latency.

The ADC may transmit a digital code converted from the precharge voltage to the processor 110. The processor 110 may compare the precharge voltage and the reference voltage based on the received digital code.

The detector 130 may detect the precharge voltage of the impedance measurement device 100 at a preset period. As the detector 130 is provided to detect the precharge voltage at a preset period, the processor 110 can quickly check whether the reference voltage of the impedance measurement device 130 has been reached.

In other words, by providing the detection unit 130, the time required for the impedance measurement device 100 to detect the impedance of the battery cell 210 can be reduced. In addition, the precharge voltage of the impedance measuring device 100 is checked through the detection unit 130, and the voltage generator 130 outputs the measured voltage depending on whether the precharge voltage reaches the reference voltage, so that the precharge voltage is the reference voltage. It is possible to prevent the impedance of the battery cell 210 from being measured without reaching .

If the precharge voltage is higher than the reference voltage, the processor 110 may control the precharge circuit 120 to maintain the voltage output and control the voltage generator 140 to output the measured voltage. The measured voltage output by the voltage generator 140 may be a sinusoidal alternating voltage with an arbitrary size and period.

As an example, the measured voltage output by the voltage generator 140 may be applied to the battery pack 200. The processor 110 may control the frequency of the alternating current voltage output by the voltage generator 140, thereby receiving information about the impedance perturbation of the battery cell according to the change in frequency. In other words, the voltage generator 140 may transmit a measured voltage to the battery pack 200 and receive information about the impedance of the battery cell 210 from the battery pack 200.

The battery pack 200 may include at least one battery cell 210. The battery pack 200 may output information about the impedance of the battery cell 210 based on the measured voltage input from the impedance measurement device 100. The impedance measurement device 100 may calculate the impedance of the battery cell 210 based on information about the impedance of the battery cell 210.

Through FIG. 2, the precharge voltage of the impedance measurement device 100 can be shown over time.

With respect to the graph in FIG. 2, the horizontal axis may represent time (unit: seconds (S)), and the vertical axis may represent voltage (unit: volts (V)).

Referring to FIG. 2 , the impedance measurement device 100 may be precharged up to the reference voltage (V ₀ ) at a first time (T ₀ ).

The second time ( _T When the reference voltage (V ₀ ) is constant, the second time ( _T

The third time (T _y ) is a preset time and may be set longer than the first time (T ₀ ). According to the embodiment, the difference between the first time (T ₀ ) and the third time (T _y ) may be referred to as a margin time. The third time (T _y ) may be a time during which the impedance measurement device 100 outputs a measurement voltage when the detection unit 130 is not provided.

If the detection unit 130 is not provided, the processor 110 cannot confirm whether the impedance measuring device 100 is charged to the reference voltage (V ₀ ), and the precharge voltage of the impedance measuring device 100 is charged to the reference voltage (V 0 ). A margin time can be set so that the measured voltage is output after reaching ₀ ). When the margin time increases, the time required to detect the impedance of the battery cell 210 may increase.

The second time (T _x ) may be closer to the first time (T ₀ ) than the third time (T _y ).

The precharge circuit 120 may precharge the impedance measurement device 100 (S100).

According to an embodiment, the processor 110 may control the impedance measurement device 100 to be precharged through the precharge circuit 120 before detecting the impedance of the battery cell 210.

The detection unit 130 may detect the precharge voltage of the impedance measurement device 100 (S200).

The detection unit 130 may detect the precharge voltage of the impedance measurement device 100 by detecting the voltage of the power storage element included in the impedance measurement device 120.

The operation of the detection unit 130 to detect the precharge voltage may be repeated at preset intervals. By detecting the precharge voltage at a preset period, the processor 110 can quickly check whether the reference voltage of the impedance measurement device 120 has been reached.

The processor 110 may compare the precharge voltage and the reference voltage (S300).

The processor 110 may compare the precharge voltage and the reference voltage and cause the voltage generator 140 to output a measured voltage according to the comparison result. The battery pack 200 that receives the measured voltage outputs information about the impedance of the battery cell 210, and the processor 110 calculates the impedance of the battery cell 210 based on the information about the impedance of the battery cell 210. can be calculated.

Through FIG. 4, a method in which the processor 110 compares the precharge voltage and the reference voltage and outputs a measured voltage can be explained in detail.

Through FIG. 4 , the step 300a in which the processor 110 compares the precharge voltage and the reference voltage according to another embodiment can be described in detail.

The processor 110 may determine whether the precharge voltage is greater than or equal to the reference voltage (S310a).

If the precharge voltage is less than the reference voltage (NO path in S310), the processor 110 may prevent the voltage generator 140 from outputting the measured voltage (S320a). If the precharge voltage is less than the reference voltage, the processor 110 may cause the precharge circuit 120 to precharge the impedance measurement device 100 (S100).

If the precharge voltage is higher than the reference voltage (YES path in S320), the processor 110 can cause the voltage generator 140 to output the measured voltage (S330a).

If the precharge voltage is higher than the reference voltage, the processor 110 may control the voltage generator 140 to output a measured voltage. The measured voltage may be applied to the battery pack 200. Information about the impedance of the battery cell 210 detected based on the measured voltage may be transmitted to the processor 110. The processor 110 may calculate the impedance spectrum of the battery cell 210 based on the received information about the impedance of the battery cell 210.

The precharge circuit 120 may precharge the impedance measurement device 100 with a direct current voltage (S100b).

As the impedance measurement device 100 is precharged with a direct current voltage, electric storage elements included in the impedance measurement device 100 may be precharged. When the impedance measurement device 100 is precharged to the reference voltage, distortion of information about the impedance of the battery cell 210 due to the circuit structure of the impedance measurement device 100 or the voltage of the battery cell 210 can be reduced.

The detector 130 may detect the precharge voltage of the impedance measurement device 100 (S200b). The operation may be substantially the same as that described in FIG. 3.

The processor 110 may compare the precharge voltage detected by the detector 130 with a reference voltage. The processor 110 may determine whether the precharge voltage is greater than or equal to the reference voltage (S310b).

If the precharge voltage is less than the reference voltage (NO path in S310b), the processor 110 may control the precharge circuit 120 to increase the direct current voltage output by the precharge circuit 120 (S320b). If the precharge voltage is less than the reference voltage, the voltage may be increased so that the direct current voltage applied to the impedance measurement device 100 reaches the reference voltage.

If the precharge voltage is less than the reference voltage, the processor 110 may perform step S100b again so that the precharge circuit 120 can perform a precharge operation for the impedance measurement device 100.

If the precharge voltage is higher than the reference voltage (YES path in S310b), the processor 110 may control the precharge circuit 120 to maintain the direct current voltage output by the precharge circuit 120 (S330b). When the precharge voltage is maintained at or above the reference voltage, the processor 110 may output a measurement voltage through the voltage generator 140 and measure the impedance of the battery cell 210.

6, a method of processing the precharge voltage detected by the detection unit 130 is shown in detail.

The detection unit 130 may convert the precharge voltage of the voltage generator 120 into a digital code (S210).

The detector 130 may transmit the detected digital code to the processor 110 (S220). Depending on the embodiment, the detector 130 may be an ADC, and by converting the precharge voltage into a digital code, the processor 110 can easily process the precharge voltage.

Referring to FIG. 7, the computing system 1000 according to an embodiment disclosed in this document may include an MCU 1010, a memory 1020, an input/output I/F 1030, and a communication I/F 1040. there is.

According to one embodiment, the computing system 1000 may be a system for performing the operation of the impedance measurement device 100 or the battery pack 200 described above.

The MCU 1010 may be a processor that executes various programs stored in the memory 1020.

For example, the MCU 1010 may correspond to the processor 110. The MCU 1010 may be a processor that processes data and/or signals necessary to manage and control the impedance measurement device 100.

In addition, the MCU 1010 adjusts the power applied to the battery pack 200 so that the impedance measurement device 100 can measure the impedance of the battery pack 200, and measures the power applied to the battery pack 200 based on the information output from the battery pack 200. Thus, it may be a processor that performs impedance calculation.

The memory 1020 may store various programs necessary for managing and controlling the impedance measurement device 100 or the battery pack 200. Additionally, the memory 1020 can store various programs necessary to measure the impedance of the battery pack 200.

For example, the memory 1020 may store various data such as voltage, current, and characteristic value data output from the battery pack 200. Additionally, the memory 102 may store a program that calculates impedance based on the voltage, current, and characteristic value data of the battery pack 200. A plurality of memories 1020 may be provided as needed.

Memory 1020 may be volatile memory or non-volatile memory. The memory 1020 as a volatile memory may use RAM, DRAM, SRAM, etc. The memory 1020 as a non-volatile memory may be ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc. The examples of memories 1020 listed above are merely examples and are not limited to these examples.

The input/output I/F (1030) is an interface that connects the MCU (1010) with input devices (not shown) such as a keyboard, mouse, and touch panel, and output devices such as a display (not shown) to transmit and receive data. can be provided.

The communication I/F 1040 is a component that can transmit and receive various data with a server, and may be various devices that can support wired or wireless communication. For example, a program for detecting the impedance of the battery pack 200 or various data can be transmitted and received from a separately provided external server through the communication I/F 1040.

As such, the computer program according to an embodiment disclosed in this document may be recorded in the memory 1020 and processed by the MCU 1010, thereby being implemented as a module that performs each operation of FIGS. 1 to 6. .

The above description is merely an illustrative explanation of the technical idea disclosed in this document, and those skilled in the art in the technical field to which the embodiments disclosed in this document belong will understand without departing from the essential characteristics of the embodiments disclosed in this document. Various modifications and variations will be possible.

Accordingly, the embodiments disclosed in this document are not intended to limit the technical ideas disclosed in this document, but rather to explain them, and the scope of the technical ideas disclosed in this document is not limited by these embodiments. The scope of protection of the technical ideas disclosed in this document shall be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope shall be interpreted as being included in the scope of rights of this document.

Claims

In the impedance measurement device that measures the impedance of a battery cell based on the measured voltage,

a precharge circuit that precharges the impedance measurement device;

a detection unit that detects a precharge voltage of the impedance measurement device;

a processor that compares the precharge voltage and a reference voltage; and

An impedance measurement device including a voltage generator that outputs the measurement voltage.
According to claim 1,

The precharge circuit is an impedance measurement device that precharges the impedance measurement device with a direct current voltage.
According to paragraph 2.

When the precharge voltage is higher than the reference voltage, the processor controls the precharge circuit to maintain the direct current voltage.
According to clause 2,

When the precharge voltage is less than the reference voltage, the processor controls the precharge circuit to increase the direct current voltage.
According to claim 1,

An impedance measurement device in which the detection unit is an analog digital converter (ADC) that converts the precharge voltage into a digital code.
According to claim 1,

An impedance measuring device in which the measured voltage is an alternating voltage.
According to claim 1,

When the precharge voltage is higher than the reference voltage, the processor controls the voltage generator to output the measurement voltage.
According to claim 1,

When the precharge voltage is less than the reference voltage, the processor controls the voltage generator not to output the measurement voltage.
According to claim 1,

An impedance measurement device wherein the reference voltage is determined based on the voltage of the battery cell and the circuit of the impedance measurement device.
According to claim 1,

An impedance measurement device wherein the detector detects the precharge voltage at a preset time period.
In a method of operating an impedance measurement device that measures the impedance of a battery cell based on the measured voltage,

precharging the impedance measurement device by a precharge circuit;

A detection unit detecting the precharge voltage of the impedance measuring device; and

A method of operating an impedance measurement device comprising the step of a processor comparing the precharge voltage and a reference voltage.
According to claim 11,

The step of the processor comparing the precharge voltage and the reference voltage is

When the precharge voltage is greater than or equal to the reference voltage, controlling a voltage generator to output a measured voltage; and

A method of operating an impedance measurement device comprising controlling the voltage generator not to output the measurement voltage when the precharge voltage is less than the reference voltage.
According to claim 11,

The step of precharging the impedance measuring device by the precharge circuit is:

A method of operating an impedance measurement device in which the precharge circuit precharges the impedance measurement device with a direct current voltage.
According to claim 13,

The step of the processor comparing the precharge voltage and the reference voltage is

When the precharge voltage is greater than or equal to the reference voltage, controlling the precharge circuit to maintain the direct current voltage; and

When the precharge voltage is less than the reference voltage, controlling the precharge circuit to increase the direct current voltage.
According to claim 11,

The step of detecting the precharge voltage is,

converting the precharge voltage into a digital code by the detection unit; and

A method of operating an impedance measurement device comprising the step of the detection unit transmitting the digital code to the processor.