JP-7856363-B2 - Battery management device and its operating method

JP7856363B2JP 7856363 B2JP7856363 B2JP 7856363B2JP-7856363-B2

Inventors

サン・ヨン・キム
ヒョン・ジン・ソン
キ・ヒョン・キム

Assignees

エルジーエナジーソリューションリミテッド

Dates

Publication Date: 20260511
Application Date: 20230901
Priority Date: 20220906

Claims (15)

A first comparator compares the voltage of the battery cell with a first reference voltage, A switching circuit sets the path through which the battery cell and the impedance calculation unit are electrically connected to either the first path or the second path, based on the comparison results from the first comparator. A battery management device including an impedance calculation unit that calculates the impedance of the battery cell based on a first voltage applied via the first path or a second voltage applied via the second path.
The second path further includes a voltage amplifier located on the second path, The battery management device according to claim 1, wherein the voltage amplifier amplifies the voltage of the battery cell to the second voltage when the path is set to the second path.
The aforementioned switching circuit is This includes a first switch located on the first path and a second switch located on the second path, If the voltage of the battery cell is equal to or greater than the first reference voltage, the first switch is opened and the second switch is opened, thereby setting the path to the first path. The battery management device according to claim 1, wherein when the voltage of the battery cell is less than the first reference voltage, the first switch is opened and the second switch is opened to set the path to the second path.
The system further includes a third switch electrically connected to the aforementioned battery cell, The battery management device according to claim 1, wherein the third switch alternately turns on and off according to a specified period to generate an alternating current that is input to the battery cell.
The battery management device according to claim 4, comprising a current control unit that adjusts the magnitude of the alternating current based on a comparison between the voltage of the battery cell and a second reference voltage.
The current control unit further includes a variable resistor placed on the path through which the alternating current flows, If the voltage of the battery cell is equal to or greater than the second reference voltage, the variable resistor is set to the first resistance value. The battery management device according to claim 5, wherein if the voltage of the battery cell is less than the second reference voltage, the variable resistor is set to a second resistance value smaller than the first resistance value.
The battery management device according to claim 1, wherein the first comparator adjusts the first reference voltage based on the change in the voltage of the battery cell over a predetermined time interval.
The first comparator is, The first reference voltage is increased when the voltage of the battery cell increases to a first specified level or more within a predetermined time interval. The battery management device according to claim 7, wherein the first reference voltage is reduced when the voltage of the battery cell decreases by a second specified level or more within a predetermined time interval.
The steps include comparing the voltage of the battery cell with the first reference voltage, The steps include: setting the path through which the battery cell and the impedance calculation unit are electrically connected to a first path or a second path based on the result of comparing the voltage of the battery cell with the first reference voltage; A method for operating a battery management device, comprising the step of calculating the impedance of the battery cell based on a first voltage applied to the impedance calculation unit via the first path, or a second voltage applied to the impedance calculation unit via the second path.
The method for operating a battery management device according to claim 9, further comprising the step of amplifying the voltage of the battery cell to the second voltage via a voltage amplifier located on the second path, when the aforementioned path is set to the second path.
The method for operating a battery management device according to claim 9, further comprising the step of alternately turning on and off a third switch electrically connected to the battery cell according to a specified period, thereby generating an alternating current (AC) to be input to the battery cell.
The method for operating a battery management device according to claim 11, further comprising the step of adjusting the magnitude of the alternating current based on the result of comparing the voltage of the battery cell with a second reference voltage.
The step of adjusting the magnitude of the alternating current is, If the voltage of the battery cell is equal to or greater than the second reference voltage, the step of setting the variable resistor placed on the path through which the alternating current flows to a first resistance value, A method for operating a battery management device according to claim 12, comprising the step of setting the variable resistor to a second resistance value smaller than the first resistance value when the voltage of the battery cell is less than the second reference voltage.
The method for operating a battery management device according to claim 9, further comprising the step of adjusting the first reference voltage based on a change in the voltage of the battery cell over a predetermined time interval.
The step of adjusting the first reference voltage is: The steps include increasing the first reference voltage when the voltage of the battery cell increases to a first specified level or more within a predetermined time interval, A method for operating a battery management device according to claim 14, comprising the step of reducing the first reference voltage when the voltage of the battery cell decreases by a second specified level or more in a predetermined time interval.

Description

This invention claims priority under Korean Patent Application No. 10-2022-0113105 dated September 6, 2022, and all content disclosed in the said Korean Patent Application is incorporated herein by reference. Embodiments disclosed herein relate to a battery management device and a method for operating the same. In recent years, research and development on rechargeable batteries has been actively pursued. Rechargeable batteries are batteries that can be charged and discharged, and the term encompasses both conventional Ni/Cd batteries, Ni/MH (nickel/metal hydride) batteries, and the more recent lithium-ion batteries. Among these, lithium-ion batteries have the advantage of having a significantly higher energy density compared to conventional Ni/Cd and Ni/MH batteries. Because lithium-ion batteries can be manufactured to be small and lightweight, they are widely used as power sources for mobile devices, and in recent years, their range of use has expanded to include electric vehicles, attracting attention as a next-generation energy storage medium. Electrochemical impedance spectroscopy (EIS) is a technique that extracts equivalent circuit parameters of a battery based on impedance values measured after applying AC power at different frequencies to the battery. It is used to estimate the battery's lifespan and condition. However, unlike typical battery cells with operating voltages of approximately 3-4.2V, battery cells with operating voltages of 2.5V or less require a separate voltage amplifier to amplify the measured voltage, as voltage measurement in the impedance measurement section becomes difficult. Furthermore, for battery cells with operating voltages of 1V or less, the current flowing through the resistor for impedance measurement drops to one-third, requiring another amplifier with an added parallel resistor to amplify the current. Therefore, conventional EIS measuring devices had to use separate circuits for measuring typical battery cells and low-voltage battery cells, depending on the battery cell's operating voltage. This figure shows the structure of an apparatus for measuring EIS in a battery cell according to one embodiment.This figure shows the structure of an apparatus for measuring EIS in a battery cell according to one embodiment.This figure shows the structure of a battery management device according to one embodiment.This diagram shows the connection relationships between components when the voltage of a battery cell is within a first voltage range, according to one embodiment.This diagram shows the connection relationships between components when the voltage of a battery cell is within a second voltage range, according to one embodiment.This diagram shows the connection relationships between components when the voltage of a battery cell is within a third voltage range, according to one embodiment.This is a flowchart illustrating the operation method of a battery management device according to one embodiment. The embodiments disclosed herein will be described in detail below with reference to illustrative drawings. Note that, in assigning reference numerals to components in each drawing, the same reference numerals have been used for identical components whenever possible, even when shown in other drawings. Furthermore, in describing the embodiments disclosed herein, if a detailed explanation of a related known configuration or function is deemed to hinder understanding of the embodiments disclosed herein, such detailed explanation will be omitted. The terminology used in this application has been selected as widely used and general terms as possible, taking into consideration their function. However, this may vary depending on the intentions or conventions of engineers in the relevant field, or the emergence of new technologies. Furthermore, in certain cases, the applicant has arbitrarily selected some terms, in which case their meanings will be described in the explanatory section of the specification. Therefore, it should be made clear that the terminology used in this application is not merely a set of names, but must be interpreted based on the substantive meaning of those terms and the overall content of this application. Furthermore, the terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. Also, in this application, expressions such as "first" and "second" are used to distinguish components from one another and do not imply any rank or order among the components. A preferred embodiment of the battery management device and its operating method will be described below with reference to the drawings. Figure 1a shows the structure of an apparatus for measuring EIS for a battery cell according to one embodiment. For a typical battery cell (B) operating within a common voltage range