Apparatus for diagnosing abnormality of battery cell and method thereof

Abstract

The invention relates to an apparatus for diagnosing an abnormality of a battery cell and a method thereof. The apparatus generates a voltage distribution of each battery cell while the vehicle is traveling, converts the voltage distribution of each battery cell from a time domain to a frequency domain, determines a frequency coefficient of each battery cell, diagnoses an abnormality of each battery cell based on a relative comparison value of the frequency coefficients between the plurality of battery cells, and determines the abnormality of each battery cell. Therefore, thermal runaway of the battery unit when the vehicle travels is prevented in advance.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Korean Patent Application No. 10 - 2023 - 0187381, filed on December 20, 2023, the entire content of which is incorporated herein for all purposes by this reference. Technical field

[0003] The present invention relates to a technique for diagnosing an abnormality of a battery cell based on a voltage distribution in a frequency domain. Background art

[0004] Generally, an electric vehicle (a vehicle driven by electric energy) is provided with a battery, which includes a plurality of battery cells that store electric energy. In this case, the battery cell includes a positive electrode current collector, a negative electrode current collector, a separator, an active material, an electrolyte, etc., and can be repeatedly charged and discharged through an electrochemical reaction between the components. In this case, in order to protect the plurality of battery cells from external impacts such as heat, vibration, etc., a battery module can be formed by combining the plurality of battery cells into one. In order to systematically manage a plurality of battery modules, a battery pack (i.e., a battery system) can be formed by using a plurality of battery modules, a battery management system (BMS), and a cooling device.

[0005] Since an electric vehicle is driven by using the electric energy stored in the battery as a power source, the performance of the vehicle is determined by the performance of the battery. Therefore, in order to improve the performance of an electric vehicle, it is necessary to manage the battery to maximize the performance of the battery.

[0006] In recent years, due to using battery cells with excellent performance to improve the power source of the vehicle and the number of battery cells gradually increasing, it is more necessary to manage the battery. This battery management is usually performed by a battery management system (BMS).

[0007] The battery management system measures unit state information including the voltage, current, temperature, etc. of the battery cells by the battery modules provided in the electric vehicle, manages the charging and discharging of the battery cells by using the unit state information and option values for controlling the battery cells, and performs unit balancing to maintain the balance between the battery cells. In this case, unit balancing is one of the control operations in which the battery management system equalizes the voltage or charge amount of the battery cells. In addition, even when the battery cells are manufactured under the same manufacturing conditions and environment, the electrical characteristics of the individual battery cells of the battery module may be different, and even when the battery cells are installed and operated in an electric vehicle, the electrical characteristics of the individual battery cells of the battery module may be different.

[0008] Due to such differences in electrical characteristics, even when charging and discharging battery cells with the same current, voltage imbalance or residual charge imbalance may occur between interconnected battery cells. The voltage imbalance or residual charge imbalance between battery cells may lead to a reduction in the available voltage range of the battery cells or a shortening of the charge and discharge cycle.

[0009] At the same time, since multiple battery cells in a battery are connected in series and parallel with each other, when a thermal runaway occurs in one battery cell, the lithium plating phenomenon may cause a micro short circuit (MSC) or an internal short circuit (ISC), resulting in thermal runaway of the entire battery.

[0010] Therefore, there is a need to provide an active diagnosis technique that analyzes the electrochemical behavior of battery cells during vehicle driving.

[0011] The information included in the background art of the present invention is only intended to enhance the understanding of the overall background of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art known to those skilled in the art. Summary of the Invention

[0012] Aspects of the present invention aim to provide a device for diagnosing abnormalities in battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in the following manner: generating a voltage distribution of each battery cell during vehicle driving; converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the frequency coefficient of each battery cell; diagnosing abnormalities in each battery cell based on the relative comparison value of the frequency coefficients between multiple battery cells.

[0013] Another aspect of the present invention provides a device for diagnosing abnormalities in battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in the following manner: generating a voltage distribution of each battery cell during vehicle driving; converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the relative comparison value of the frequency coefficients of each battery cell; diagnosing that a battery cell with a relative comparison value exceeding a threshold has an abnormality.

[0014] Another aspect of the present invention provides a device for diagnosing abnormalities in battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in the following manner: repeatedly generating a voltage distribution of each battery cell during vehicle driving; converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the relative comparison value of the frequency coefficients of each battery cell; diagnosing that a battery cell with the number of detected relative comparison values exceeding a threshold exceeding a preset number has an abnormality.

[0015] Another aspect of the present invention provides a device for diagnosing abnormalities of battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in advance by: generating a voltage distribution of each battery cell every time the vehicle drives; converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining a relative comparison value of the frequency coefficients of each battery cell; recording the identification number of the battery cell corresponding to the maximum value in the relative comparison values and the identification number of the battery cell corresponding to the minimum value in the relative comparison values; and diagnosing that a battery cell whose identification number is recorded more than a preset number of times has an abnormality.

[0016] Another aspect of the present invention provides a device for diagnosing abnormalities of battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in advance by: generating a current distribution and a voltage distribution of each battery cell while the vehicle is driving; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the frequency coefficients of each battery cell; and diagnosing abnormalities of each battery cell based on the relative comparison values of the frequency coefficients between battery cells.

[0017] Another aspect of the present invention provides a device for diagnosing abnormalities of battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in advance by: generating a current distribution and a voltage distribution of each battery cell while the vehicle is driving; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the relative comparison value of the frequency coefficients of each battery cell; and diagnosing that each battery cell with a relative comparison value exceeding a threshold has an abnormality.

[0018] Another aspect of the present invention provides a device for diagnosing abnormalities of battery cells, the device being configured to prevent thermal runaway of battery cells during vehicle driving in advance by: repeatedly generating a current distribution and a voltage distribution of each battery cell while the vehicle is driving; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining the relative comparison value of the frequency coefficients of each battery cell; and diagnosing that a battery cell whose detected number of times of the relative comparison value exceeding the threshold exceeds a preset number of times has an abnormality.

[0019] Another aspect of the present invention provides a device for diagnosing an abnormality of a battery cell, the device being configured to prevent thermal runaway of the battery cell during vehicle travel in the following manner: generating a current distribution and a voltage distribution of each battery cell each time the vehicle travels; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell from the time domain to the frequency domain; determining a relative comparison value of the frequency coefficients of each battery cell; recording the identification number of the battery cell corresponding to the maximum value in the relative comparison values and the identification number of the battery cell corresponding to the minimum value in the relative comparison values; and diagnosing that an abnormality has occurred in the battery cell whose identification number has been recorded more than a preset number of times.

[0020] The technical problems solved by the present invention are not limited to the above problems, and those skilled in the art to which the present invention pertains will clearly understand any other technical problems not mentioned herein through the following description. In addition, it can be easily understood that the objectives and advantages of the present invention can be achieved by the units and combinations thereof recited in the claims.

[0021] According to one aspect of the present invention, a device for diagnosing an abnormality of a battery cell includes a battery and a controller, the battery including a plurality of battery cells, and the controller generating a voltage distribution of each battery cell during vehicle travel, converting the voltage distribution of each battery cell from the time domain to the frequency domain, determining the frequency coefficient of each battery cell, and diagnosing an abnormality of each battery cell based on a relative comparison value of the frequency coefficients among the plurality of battery cells.

[0022] According to an exemplary embodiment of the present invention, the controller may be configured to: determine a relative comparison value of each frequency of each battery cell, and among the relative comparison values of each frequency, determine that an abnormality has occurred in the battery cell in which the detected relative comparison value exceeds a threshold.

[0023] According to an exemplary embodiment of the present invention, the controller may be configured to: determine the relative comparison value of each frequency of each battery cell multiple times, and among the relative comparison values of each frequency, determine that an abnormality has occurred in the battery cell in which the number of times the detected relative comparison value exceeds a threshold exceeds a preset number of times.

[0024] According to an exemplary embodiment of the present invention, the controller may be configured to: each time the vehicle travels, determine the relative comparison value of each frequency of each battery cell, among the relative comparison values of each frequency, record the identification number of the battery cell corresponding to the maximum value and the identification number of the battery cell corresponding to the minimum value, and determine that an abnormality has occurred in the battery cell whose identification number has been recorded more than a preset number of times.

[0025] According to an exemplary embodiment of the present invention, among the relative comparison values of the respective frequencies, the controller may determine that a battery cell in which the number of times the maximum value is detected exceeds a preset number has an abnormality.

[0026] According to an exemplary embodiment of the present invention, among the relative comparison values of the respective frequencies, the controller may determine that a battery cell in which the number of times the minimum value is detected exceeds a preset number has an abnormality.

[0027] According to an exemplary embodiment of the present invention, the controller is further configured to: generate a current distribution of each battery cell when the vehicle is running, determine whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution, and diagnose an abnormality of each battery cell when it is determined that the voltage distribution in the frequency domain includes high-frequency components.

[0028] According to an exemplary embodiment of the present invention, the controller may be configured to: when the variance of the current value exceeds a first threshold and the integral value of the absolute value of the current change amount exceeds a second threshold within a preset time under a load state, determine that the voltage distribution in the frequency domain includes high-frequency components.

[0029] According to an exemplary embodiment of the present invention, the controller may be configured to: when the variance of the current value exceeds a first threshold within a preset time under a load state, determine that the voltage distribution in the frequency domain includes high-frequency components.

[0030] According to an exemplary embodiment of the present invention, the controller may be configured to: when the integral value of the absolute value of the current change amount exceeds a second threshold within a preset time under a load state, determine that the voltage distribution in the frequency domain includes high-frequency components.

[0031] According to another aspect of the present invention, a method for diagnosing an abnormality of a battery cell includes: when a vehicle including a plurality of battery cells is running, generating a voltage distribution of each battery cell by a controller; converting the voltage distribution of each battery cell from the time domain to the frequency domain by the controller; determining a frequency coefficient of each battery cell by the controller; and diagnosing an abnormality of each battery cell based on a relative comparison value of the frequency coefficients among the plurality of battery cells by the controller.

[0032] According to an exemplary embodiment of the present invention, diagnosing an abnormality of each battery cell may include: determining a relative comparison value of each frequency of each battery cell by the controller; and among the relative comparison values, determining that a battery cell in which the relative comparison value exceeds a threshold has an abnormality by the controller.

[0033] According to an exemplary embodiment of the present invention, diagnosing an abnormality of each battery cell may include: determining, by a controller, relative comparison values of respective frequencies of each battery cell multiple times; among the relative comparison values of the respective frequencies, determining, by the controller, that a battery cell in which the number of times the detected relative comparison value exceeds a threshold value exceeds a preset number has an abnormality.

[0034] According to an exemplary embodiment of the present invention, diagnosing an abnormality of each battery cell may include: when the vehicle travels each time, determining, by a controller, relative comparison values of respective frequencies of each battery cell; recording, by the controller, the identification number of the battery cell corresponding to the maximum value and the identification number of the battery cell corresponding to the minimum value among the relative comparison values of the respective frequencies; determining, by the controller, that a battery cell with an identification number recorded more than a preset number of times has an abnormality.

[0035] According to an exemplary embodiment of the present invention, diagnosing that a battery cell with an identification number recorded more than a preset number of times has an abnormality may include: among the relative comparison values of the respective frequencies, determining, by the controller, that a battery cell in which the number of times the detected maximum value exceeds a preset number has an abnormality.

[0036] According to an exemplary embodiment of the present invention, diagnosing that a battery cell with an identification number recorded more than a preset number of times has an abnormality may include: among the relative comparison values of the respective frequencies, determining, by the controller, that a battery cell in which the number of times the detected minimum value exceeds a preset number has an abnormality.

[0037] According to an exemplary embodiment of the present invention, generating a voltage distribution of each battery cell may further include: when the vehicle travels, generating, by a controller, a current distribution of each battery cell; determining, by the controller, whether the voltage distribution in the frequency domain includes a high-frequency component based on the current distribution.

[0038] According to an exemplary embodiment of the present invention, determining whether the voltage distribution includes a high-frequency component may include: when, within a preset time and under a load state, the variance of the current value exceeds a first threshold and the integral value of the absolute value of the current change amount exceeds a second threshold, determining, by the controller, that the voltage distribution in the frequency domain includes a high-frequency component.

[0039] According to an exemplary embodiment of the present invention, determining whether the voltage distribution includes a high-frequency component may include: when, within a preset time and under a load state, the variance of the current value exceeds a first threshold, determining, by the controller, that the voltage distribution in the frequency domain includes a high-frequency component.

[0040] According to an exemplary embodiment of the present invention, determining whether the voltage distribution includes a high-frequency component may include: when, within a preset time and under a load state, the integral value of the absolute value of the current change amount exceeds a second threshold, determining, by the controller, that the voltage distribution in the frequency domain includes a high-frequency component.

[0041] The method and apparatus of the present invention have other characteristics and advantages, which will be apparent from the accompanying drawings incorporated herein and the subsequent detailed description, or will be described in detail in the accompanying drawings incorporated herein and the subsequent detailed description, which together are used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a block diagram showing the configuration of a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention;

[0043] Figure 2 is a schematic diagram showing an example of the result of converting the voltage distribution of a battery cell from the time domain to the frequency domain by a controller provided in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention;

[0044] Figure 3 is a schematic diagram showing a process of determining a frequency coefficient of a battery cell by a controller provided in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention;

[0045] Figure 4 is a schematic diagram showing a process of determining frequency coefficients of a plurality of battery cells by a controller provided in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention;

[0046] Figure 5 is a schematic diagram showing a process of determining a relative comparison value of frequency coefficients of a plurality of battery cells by a controller provided in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention;

[0047] Figure 6 is a schematic diagram showing an example of an identification number of each battery cell recorded by a controller provided in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention for each trip;

[0048] Figure 7 is a flowchart showing a method for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention; and

[0049] Figure 8 is a block diagram showing a computing system for performing a method for diagnosing an abnormality of a battery cell according to various exemplary embodiments of the present invention.

[0050] It should be understood that the accompanying drawings are not drawn to scale and are merely schematic illustrations of the features for explaining the basic principles of the present invention in a suitably simplified manner. The specific design features of the present invention disclosed herein, such as specific dimensions, directions, positions, and shapes, will be determined in part by the specific application and use environment.

[0051] In the drawings, throughout the several views, like reference numerals refer to the same or equivalent parts of the present invention. Detailed Description of the Invention

[0052] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. Although the present invention will be described in conjunction with the exemplary embodiments of the present invention, it will be understood that this specification is not intended to limit the present invention to those exemplary embodiments. On the contrary, the present invention is intended to cover not only the exemplary embodiments of the present invention, but also various alternative forms, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the present invention as defined by the appended claims.

[0053] Hereinafter, various exemplary embodiments of the present invention will be described in detail with reference to the exemplary drawings. When adding reference numerals to the components of each drawing, it should be noted that even if the same or equivalent components are shown in other drawings, they are designated by the same reference numerals. In addition, when describing the exemplary embodiments of the present invention, the detailed description of related known configurations or functions will be omitted when it is determined that such detailed description will interfere with the understanding of the exemplary embodiments of the present invention.

[0054] In addition, when describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used herein. The terms provided are only used to distinguish an element from other elements, and the nature, order, sequence, and quantity of the elements are not limited by the terms. In addition, unless otherwise defined, all terms (including technical terms or scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. Terms defined in a general dictionary should be interpreted as having a meaning consistent with the contextual meaning of the related art, and should not be interpreted as ideal or overly formal meanings unless clearly defined in the specification of the present invention.

[0055] Figure 1 is a block diagram showing the configuration of a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention.

[0056] As Figure 1As shown, the device 100 for diagnosing abnormalities of battery cells may include a storage device 10, a communication device 20, and a controller 30. In this case, according to an embodiment of the device 100 for diagnosing abnormalities of battery cells according to an exemplary embodiment of the present invention, components may be combined with each other to be implemented as one, or some components may be omitted. For example, the device 100 for diagnosing abnormalities of battery cells may be implemented within a battery management system (BMS), or the BMS may be implemented to execute the functions of the device 100 for diagnosing abnormalities of battery cells.

[0057] Regarding each component, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating a voltage distribution of each battery cell 210 while the vehicle is running; converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining a frequency coefficient of each battery cell 210; and diagnosing an abnormality of each battery cell 210 based on a relative comparison value of the frequency coefficients between each battery cell 210. The storage device 10 may store the diagnosis results of the controller 30.

[0058] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating a voltage distribution of each battery cell 210 while the vehicle is running; converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining a relative comparison value of the frequency coefficients of each battery cell 210; and diagnosing that an abnormality has occurred in the battery cell 210 whose relative comparison value exceeds a threshold.

[0059] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: repeatedly generating a voltage distribution of each battery cell 210 while the vehicle is running; converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining a relative comparison value of the frequency coefficients of each battery cell 210; and diagnosing that an abnormality has occurred in the battery cell 210 in which the number of times the detected relative comparison value exceeds the threshold exceeds a preset number of times.

[0060] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating a voltage distribution of each battery cell 210 every time the vehicle runs; converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining a relative comparison value of the frequency coefficients of each battery cell 210; recording the identification number of the battery cell corresponding to the maximum value in the relative comparison values and the identification number of the battery cell corresponding to the minimum value in the relative comparison values; and diagnosing that an abnormality has occurred in the battery cell whose identification number is recorded more than a preset number of times.

[0061] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating the current distribution and voltage distribution of each battery cell 210 while the vehicle is running; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining the frequency coefficients of each battery cell 210; and diagnosing abnormalities of each battery cell 210 based on the relative comparison values of the frequency coefficients between each battery cell 210. The storage device 10 may store the diagnosis results of the controller 30.

[0062] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating the current distribution and voltage distribution of each battery cell 210 while the vehicle is running; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining the relative comparison values of the frequency coefficients of each battery cell 210; and diagnosing that abnormalities have occurred in each battery cell 210 whose relative comparison values exceed the threshold.

[0063] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: repeatedly generating the current distribution and voltage distribution of each battery cell 210 while the vehicle is running; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining the relative comparison values of the frequency coefficients of each battery cell 210; and diagnosing that abnormalities have occurred in the battery cells 210 whose detected number of times the relative comparison values exceed the threshold exceeds the preset number of times.

[0064] In addition, the storage device 10 may store various logics, algorithms, and programs required in the following processes: generating the current distribution and voltage distribution of each battery cell 210 each time the vehicle runs; determining whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution; when it is determined that the voltage distribution in the frequency domain includes high-frequency components, converting the voltage distribution of each battery cell 210 from the time domain to the frequency domain; determining the relative comparison values of the frequency coefficients of each battery cell 210; recording the identification numbers of the battery cells corresponding to the maximum value among the relative comparison values and the identification numbers of the battery cells corresponding to the minimum value among the relative comparison values; and diagnosing that abnormalities have occurred in the battery cells whose identification numbers are recorded more than the preset number of times.

[0065] The communication device 20 is a module that provides a communication interface with the battery management server 300 or the vehicle management server 400, and the communication device 20 sends the result diagnosed by the controller 30 to the battery management server 300 or the vehicle management server. For example, the communication device 20 may send a message including information related to the battery cell 210 diagnosed as abnormal to the battery management server 300 or the vehicle management server 400. The communication device 20 may include at least one of a mobile communication module, a wireless Internet module, and a short-range communication module.

[0066] The mobile communication module may communicate with the battery management server 300 or the vehicle management server 400 through a mobile communication network constructed according to a technical standard or communication scheme for mobile communication (for example, Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Code Division Multiple Access 2000 (CDMA2000), Enhanced Voice Data Optimized or Enhanced Voice Data (EV-DO), Wideband CDMA (WCDMA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), Long-Term Evolution (LTE), Long-Term Evolution Advanced (LTE-A), etc.).

[0067] The wireless Internet module, as a module for wireless Internet access, may communicate with the battery management server 300 or the vehicle management server 400 through Wireless LAN (WLAN), Wi-Fi, Wi-Fi Direct, Digital Living Network Alliance (DLNA), Wireless Broadband (WiBro), Worldwide Interoperability for Microwave Access (WiMAX), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), Long-Term Evolution (LTE), Long-Term Evolution Advanced (LTE-A), etc.

[0068] The short-range communication module may support short-range communication with the battery management server 300 or the vehicle management server 400 by using at least one of Bluetooth TM , Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra-Wideband (UWB), ZigBee, Near Field Communication (NFC), and Wireless Universal Serial Bus (USB) technologies.

[0069] The battery management server 300 may receive the diagnostic result from the device 100 for diagnosing the abnormality of the battery cell provided in each vehicle, and may manage the state of the battery cell provided in each vehicle. The vehicle management server 400 may receive the diagnostic result from the device 100 for diagnosing the abnormality of the battery cell provided in each vehicle, and may manage the state of each vehicle.

[0070] The controller 30 may be electrically connected to each component and may perform overall control such that each component is configured to perform its function. The controller 30 may be implemented in the form of hardware or software, or may be implemented as a combination of hardware and software. The controller 30 may be implemented as a microprocessor, but is not limited thereto.

[0071] The controller 30 may be configured to generate the voltage distribution of each battery cell 210 while the vehicle is running, convert the voltage distribution of each battery cell 210 from the time domain to the frequency domain, determine the frequency coefficient of each battery cell 210, and diagnose the abnormality of each battery cell 210 based on the relative comparison value of the frequency coefficients between the battery cells 210. In this case, the controller 30 may be configured to generate the voltage distribution of each battery cell 210 at a preset time unit (e.g., 10 seconds) while the vehicle is running.

[0072] The controller 30 may be configured to issue a warning to the user via the cluster in the vehicle when an abnormality occurs in each battery cell 210.

[0073] Hereinafter, reference will be made to Figures 2 to 6 describe the operation of the controller 30.

[0074] Figure 2 is a schematic diagram showing an example of the result of converting the voltage distribution of a battery cell from the time domain to the frequency domain by a controller in a device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention.

[0075] As Figure 2 shown, the controller 30 may convert the voltage distribution 21 in the time domain into the voltage distribution 22 in the frequency domain. In this case, the voltage distribution 22 in the frequency domain may include a plurality of high-frequency components f0, f1, f2, f3, f4, and f5. However, among these high-frequency components, f1, f2, and f3 have the greatest influence on diagnosing the abnormality of the battery cell 210. That is, the controller 30 may check whether the voltage of a predetermined battery cell 210 in the frequency domain is significantly less than or greater than the voltage of other battery cells 210. This cannot be observed in the time domain.

[0076] In this case, the controller 30 may convert the voltage distribution 21 in the time domain into the voltage distribution 21 in the frequency domain based on one of the Fourier transform (FT) algorithm, the fast Fourier transform (FFT) algorithm, the non-linear frequency response analysis (NFRA) algorithm, and the wavelet transform (WT) algorithm.

[0077] Figure 3It is a schematic diagram showing the process of determining the frequency coefficients of battery cells by a controller in a device for diagnosing abnormalities of battery cells according to an exemplary embodiment of the present invention.

[0078] In Figure 3 it, reference numeral 310 represents the sine wave form of the high-frequency component f1, reference numeral 311 represents the frequency coefficient of the high-frequency component f1, reference numeral 320 represents the sine wave form of the high-frequency component f2, reference numeral 321 represents the frequency coefficient of the high-frequency component f2, reference numeral 330 represents the sine wave form of the high-frequency component f3, and reference numeral 331 represents the frequency coefficient of the high-frequency component f3. In this case, the frequency coefficient represents the amplitude of the sine wave.

[0079] As Figure 3 shown, the voltage distribution 21 in the time domain can be expressed as the sum of the high-frequency components f1310, f2320, and f3330 in the frequency domain. Therefore, the controller 30 can be configured to determine the frequency coefficient 310 of f1, the frequency coefficient 320 of f2, and the frequency coefficient 330 of f3 for each battery cell 210.

[0080] Figure 4 It is a schematic diagram showing the process of determining the frequency coefficients of multiple battery cells by a controller in a device for diagnosing abnormalities of battery cells according to an exemplary embodiment of the present invention.

[0081] In Figure 4 it, f0 is a direct current (DC) component, which only represents the difference between the voltages of each battery cell 210 and is not used to diagnose the abnormalities of each battery cell 210. Except for the frequency coefficient of f0, the frequency coefficients of the remaining f1, f2, and f3 can be used to diagnose the abnormalities of each battery cell 210.

[0082] For example, when the battery 200 is implemented by a first battery cell, a second battery cell, and a third battery cell, the controller 30 can select f1, f2, and f3 from the high-frequency components of the first battery cell and determine the frequency coefficient of f1, the frequency coefficient of f2, and the frequency coefficient of f3. The controller 30 can select f1, f2, and f3 from the high-frequency components of the second battery cell and determine the frequency coefficient of f1, the frequency coefficient of f2, and the frequency coefficient of f3. In addition, the controller 30 can select f1, f2, and f3 from the high-frequency components of the third battery cell and determine the frequency coefficient of f1, the frequency coefficient of f2, and the frequency coefficient of f3.

[0083] Therefore, as Figure 4As shown, the frequency coefficients of f1 include the frequency coefficients of f1 of the first battery cell, the frequency coefficients of f1 of the second battery cell, and the frequency coefficients of f1 of the third battery cell. The frequency coefficients of f2 include the frequency coefficients of f2 of the first battery cell, the frequency coefficients of f2 of the second battery cell, and the frequency coefficients of f2 of the third battery cell. In addition, the frequency coefficients of f3 include the frequency coefficients of f3 of the first battery cell, the frequency coefficients of f3 of the second battery cell, and the frequency coefficients of f3 of the third battery cell.

[0084] Figure 5 is a schematic diagram showing a process of determining relative comparison values of frequency coefficients of a plurality of battery cells by a controller in a device for diagnosing abnormalities of battery cells according to an exemplary embodiment of the present invention.

[0085] As Figure 5 shown, the relative comparison value DDFT determined by the controller 30 for Cell 1 may include a relative comparison value of 101.4% for f1, a relative comparison value of 101.2% for f2, and a relative comparison value of 100.9% for f3. In addition, the relative comparison value determined by the controller 30 for Cell 2 may include a relative comparison value of 99.9% for f1, a relative comparison value of 99.9% for f2, and a relative comparison value of 100.1% for f3. In addition, the relative comparison value determined by the controller 30 for Cell 3 may include a relative comparison value of 100.2% for f1, a relative comparison value of 98.4% for f2, and a relative comparison value of 102.4% for f3. In addition, the relative comparison value determined by the controller 30 for Cell 100 may include a relative comparison value of 101.7% for f1, a relative comparison value of 100.0% for f2, and a relative comparison value of 99.9% for f3. In this case, the controller 30 may repeatedly generate a table as Figure 5 shown while the vehicle is running. In this case, one table represents the DDFT of the voltage distribution of each battery cell within 10 seconds.

[0086] Meanwhile, for example, the controller 30 may be configured to determine the relative comparison value DDFT based on Equation 1 below.

[0087] [Equation 1]

[0088]

[0089] where C A represents the average value of the frequency coefficients of each frequency component, and C T represents the target frequency coefficient of each frequency component.

[0090] For example, when the frequency coefficient of the high-frequency component f1 of the first battery unit is 200, the frequency coefficient of the high-frequency component f1 of the second battery unit is 230, and the frequency coefficient of the high-frequency component f1 of the third battery unit is 200, C A is 210. Therefore, the DDFT of f1 of the first battery unit is 95.2%, the DDFT of f1 of the second battery unit is 109.5%, and the DDFT of f1 of the third battery unit is 95.2%.

[0091] As an exemplary embodiment of the present invention, when the frequency coefficient of the high-frequency component f2 of the first battery unit is 210, the frequency coefficient of the high-frequency component f2 of the second battery unit is 230, and the frequency coefficient of the high-frequency component f2 of the third battery unit is 220, C A is 220. Therefore, the DDFT of f2 of the first battery unit is 95.4%, the DDFT of f2 of the second battery unit is 104.5%, and the DDFT of f2 of the third battery unit is 100.0%.

[0092] In this case, the controller 30 can further generate the current distribution of each battery unit when the vehicle is running, determine whether the voltage distribution in the frequency domain includes high-frequency components based on the current distribution, and when it is determined that the voltage distribution in the frequency domain includes high-frequency components, start the process of diagnosing the abnormality of each battery unit 210.

[0093] In this case, when not in the no-load (0 A) state within a preset time (for example, 10 seconds), the variance of the current value within 10 seconds exceeds a threshold (for example, α), and the integral result of the absolute value of the current change within 10 seconds exceeds a threshold (for example, β), the controller 30 can start the process of diagnosing the abnormality of each battery unit 210.

[0094] In addition, when not in the no-load (0 A) state within a preset time (for example, 10 seconds) and the variance of the current value within 10 seconds exceeds a threshold (for example, α), the controller 30 can start the process of diagnosing the abnormality of each battery unit 210.

[0095] In addition, when not in the no-load (0 A) state within a preset time (for example, 10 seconds) and the integral result of the absolute value of the current change within 10 seconds exceeds a threshold (for example, β), the controller 30 can start the process of diagnosing the abnormality of each battery unit 210.

[0096] Meanwhile, as Figure 5 shown, in the state of determining the relative comparison values of the high-frequency components of each battery unit 210, the controller 30 can diagnose whether each battery unit 210 is abnormal in the following various ways.

[0097] As various exemplary embodiments of the present invention, the controller 30 may diagnose that among the relative comparison values of respective high-frequency components, an abnormality has occurred in the battery cell 210 in which the relative comparison value exceeds a threshold value.

[0098] For example, when the threshold value is set to 101.5%, the controller 30 may diagnose that Figure 5 the cell 100 has an abnormality.

[0099] As various exemplary embodiments of the present invention, the controller 30 may diagnose that an abnormality has occurred in the battery cell 210 in which the number of times the detected relative comparison value exceeds the threshold value exceeds a preset number of times.

[0100] For example, as Figure 5 shown, when generating 10 relative comparison values of respective high-frequency components of respective battery cells 210 in units of 10 seconds, and the battery cell in which the number of times the relative comparison value exceeds the threshold value exceeds the preset number of times is cell 1, the controller 30 may diagnose that an abnormality has occurred in cell 1.

[0101] As various exemplary embodiments of the present invention, the controller 30 may be configured to determine, for each vehicle travel (per trip), the relative comparison value of the frequency coefficient of respective high-frequency components of respective battery cells 210, record the identification number of the battery cell corresponding to the maximum value and the identification number of the battery cell corresponding to the minimum value among the relative comparison values of respective high-frequency components, and diagnose that an abnormality has occurred in the battery cell whose identification number is recorded more than the preset number of times. In this case, the controller 30 may perform the process of determining the relative comparison value of the frequency coefficient of respective high-frequency components of respective battery cells 210 at least once during vehicle travel.

[0102] Figure 6 is a schematic diagram showing an example of the identification number of each battery cell recorded by the controller in the device for diagnosing an abnormality of a battery cell according to an exemplary embodiment of the present invention for each trip.

[0103] In trip 1, the battery cell with the detected maximum relative comparison value is the 17th battery cell, and the battery cell with the detected minimum relative comparison value is the 4th battery cell. In this case, a trip represents the time from when the vehicle starts traveling to when the vehicle stops traveling (turns off the engine).

[0104] In trip 2, the battery cell with the detected maximum relative comparison value is the 21st battery cell, and the battery cell with the detected minimum relative comparison value is the 4th battery cell.

[0105] In trip 3, the battery cell with the detected maximum relative comparison value is the 21st battery cell, and the battery cell with the detected minimum relative comparison value is the 4th battery cell.

[0106] In Run 4, the battery cell with the largest relative comparison value detected is cell No. 84, and the battery cell with the smallest relative comparison value detected is cell No. 34.

[0107] In Run 5, the battery cell with the largest relative comparison value detected is cell No. 42, and the battery cell with the smallest relative comparison value detected is cell No. 4.

[0108] In Run 6, the battery cell with the largest relative comparison value detected is cell No. 33, and the battery cell with the smallest relative comparison value detected is cell No. 4.

[0109] In Run 7, the battery cell with the largest relative comparison value detected is cell No. 32, and the battery cell with the smallest relative comparison value detected is cell No. 4.

[0110] In Run 8, the battery cell with the largest relative comparison value detected is cell No. 33, and the battery cell with the smallest relative comparison value detected is cell No. 97.

[0111] In Run 9, the battery cell with the largest relative comparison value detected is cell No. 14, and the battery cell with the smallest relative comparison value detected is cell No. 4.

[0112] In Run 10, the battery cell with the largest relative comparison value detected is cell No. 75, and the battery cell with the smallest relative comparison value detected is cell No. 12.

[0113] As Figure 6 shown, it can be understood that as a result of the controller 30 recording the identification numbers of the battery cells with the largest relative comparison value and the identification numbers of the battery cells with the smallest relative comparison value for 10 runs, cell No. 4 is recorded 7 times. Therefore, the controller 30 can diagnose that an abnormality has occurred in cell No. 4.

[0114] Figure 7 is a flowchart showing a method for diagnosing an abnormality in a battery cell according to an exemplary embodiment of the present invention.

[0115] First, in 701, when a vehicle equipped with a plurality of battery cells 210 is running, the controller 30 can be configured to generate a voltage distribution of each battery cell 210.

[0116] Accordingly, in 702, the controller 30 can convert the voltage distribution of each battery cell 210 from the time domain to the frequency domain.

[0117] Accordingly, in 703, the controller 30 can be configured to determine the frequency coefficients of each battery cell 210.

[0118] Accordingly, in 704, the controller 30 can diagnose abnormalities of the respective battery cells 210 based on the relative comparison values of the frequency coefficients between the battery cells 210.

[0119] Accordingly, in response to an abnormality occurring in each of the battery cells 210, the controller 30 can issue a warning to the user via a combination instrument panel in the vehicle. In response to an abnormality occurring in each of the battery cells 210, the controller 30 can turn on a warning light in the vehicle. In response to an abnormality occurring in each of the battery cells 210, the controller 30 can limit the charging amount or discharging amount of the battery 200 (i.e., the power of the vehicle). In response to an abnormality occurring in each of the battery cells 210, the controller 30 can control the driving strategy of the vehicle.

[0120] Figure 8 is a block diagram of a computing system illustrating a method for diagnosing an abnormality of a battery cell for performing various exemplary embodiments according to the present invention.

[0121] Reference Figure 8 , the method for diagnosing an abnormality of a battery cell according to the above-described exemplary embodiment of the present invention can be implemented by a computing system 1000. The computing system 1000 can include at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, a storage device 1600, and a network interface 1700 connected via a system bus 1200.

[0122] The processor 1100 can be a central processing unit (CPU) or a semiconductor device for processing instructions stored in the memory 1300 and / or the storage device 1600. The memory 1300 and the storage device 1600 can include various types of volatile or non-volatile storage media. For example, the memory 1300 can include a read-only memory (ROM) 1310 and a random access memory (RAM) 1320.

[0123] Accordingly, the processes of the methods or algorithms described in connection with the exemplary embodiments of the present invention may be implemented directly by hardware, software modules, or combinations thereof executed by the processor 1100. The software modules may reside on a storage medium (i.e., the memory 1300 and / or the storage device 1600), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, a hard disk, a solid state drive (SSD), a removable disk, or a CD-ROM. The exemplary storage medium is coupled to the processor 1100, and the processor 1100 may read information from, and write information to, the storage medium. In another approach, the storage medium may be integrated with the processor 1100. The processor 1100 and the storage medium may reside in an application specific integrated circuit (ASIC). The ASIC may reside within a user terminal. In another approach, the processor 1100 and the storage medium may exist as separate components within the user terminal.

[0124] The control device may be at least one microprocessor operated by a predetermined program, and the predetermined program may include a series of instructions for performing the methods included in the various exemplary embodiments of the present invention described above.

[0125] In the various exemplary embodiments of the present invention, each of the above operations may be performed by the control device, and the control device may be configured by a plurality of control devices or an integrated single control device.

[0126] In the various exemplary embodiments of the present invention, the memory and the processor may be provided as one chip, or provided as separate chips.

[0127] In the various exemplary embodiments of the present invention, the scope of the present invention includes software or machine-executable instructions (e.g., an operating system, an application program, firmware, a program, etc.) for enabling the operations of the methods according to the various embodiments to be executed on a device or a computer, and a non-volatile computer-readable medium including such software or instructions stored thereon and executable on the device or the computer.

[0128] Furthermore, terms such as "unit", "module", etc. included in the specification denote units for performing at least one function or operation, which may be implemented by hardware, software, or a combination thereof.

[0129] In the exemplary embodiments of the present invention, a vehicle may be referred to based on the concept including various means of transportation. In some cases, a vehicle may be interpreted based on the concept including not only various land vehicles traveling on roads (e.g., cars, motorcycles, large trucks, and buses) but also various means of transportation such as airplanes, drones, ships, etc.

[0130] For the purposes of facilitating explanation and precisely defining the appended claims, the terms "upper", "lower", "inner", "outer", "above", "below", "upward", "downward", "front", "rear", "back", "inner side", "outer side", "inwardly", "outwardly", "internal", "external", "inner side", "outer side", "forward" and "backward" are used to describe the features of the exemplary embodiments with reference to the positions of these features shown in the accompanying drawings. It will be further understood that the term "connected" or its derivatives refer to both direct connection and indirect connection.

[0131] The term "and / or" may include combinations of multiple related listed items or any one of multiple related listed items. For example, "A and / or B" includes all three cases such as "A", "B", and "A and B".

[0132] In the exemplary embodiments of the present invention, "at least one of A and B" may refer to "at least one of A or B" or "at least one of a combination of at least one of A and B". In addition, "one or more of A and B" may refer to "one or more of A or B" or "one or more of a combination of one or more of A and B".

[0133] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0134] In the exemplary embodiments of the present invention, it should be understood that terms such as "comprising" or "having" are intended to indicate the presence of the features, numerical values, steps, operations, elements, components, or combinations thereof described in the specification, and do not exclude the possibility of adding or existing one or more other features, numerical values, steps, operations, elements, components, or combinations thereof.

[0135] According to the exemplary embodiments of the present invention, components may be combined with each other to be implemented as one, or some components may be omitted.

[0136] The foregoing description of the specific exemplary embodiments of the present invention has been presented for purposes of illustration and description. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and changes are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain the specific principles of the invention and its practical application, so that others skilled in the art can implement and utilize the various exemplary embodiments of the invention and their different alternative forms and modifications. The scope of the present invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A device for diagnosing an abnormality of a battery cell, the device comprising: A battery comprising a plurality of battery cells; The controller is configured as: generating a voltage profile of each battery cell in response to vehicle travel, Convert the voltage distribution of each battery cell from the time domain to the frequency domain, Determine the frequency coefficient of each battery cell based on the frequency domain, The abnormality of each battery cell is diagnosed based on the relative comparison value of the frequency coefficient between the plurality of battery cells.

2. The apparatus for diagnosing abnormality of a battery cell according to claim 1, wherein: The controller is further configured to: Determine the relative comparison value of each frequency of each battery cell, Among the relative comparison values ​​of the respective frequencies, it is determined that an abnormality has occurred in a battery cell in which a relative comparison value exceeding a threshold value is detected among the battery cells.

3. The apparatus for diagnosing abnormality of a battery cell according to claim 1, wherein: The controller is further configured to: Determine the relative comparison value of each frequency of each battery cell multiple times, Among the relative comparison values ​​of the respective frequencies, it is determined that an abnormality has occurred in a battery cell in which the relative comparison value detected to have exceeded a threshold value more than a preset number of times.

4. The apparatus for diagnosing abnormality of a battery cell according to claim 1, wherein: The controller is further configured to: During each vehicle driving, the relative comparison values ​​of the frequencies of the various battery cells are determined. In the relative comparison values ​​of the respective frequencies, the identification number of the battery cell corresponding to the maximum value and the identification number of the battery cell corresponding to the minimum value are recorded, It is determined that an abnormality has occurred in a battery cell having an identification number recorded more than a preset number of times among the battery cells.

5. The apparatus for diagnosing abnormality of a battery cell according to claim 4, wherein: The controller is further configured to determine, among the relative comparison values ​​of the respective frequencies, that an abnormality has occurred in a battery cell in which the maximum value has been detected more than a preset number of times.

6. The apparatus for diagnosing abnormality of a battery cell according to claim 4, wherein: The controller is further configured to determine, among the relative comparison values ​​of the respective frequencies, that a battery cell in which a minimum value is detected more than a preset number of times has an abnormality.

7. The apparatus for diagnosing abnormality of a battery cell according to claim 1, wherein: The controller is further configured to: generating a current profile of each battery cell in response to vehicle travel, determining whether the voltage distribution in the frequency domain includes a high-frequency component based on the current distribution, In response to the controller determining that the voltage distribution in the frequency domain includes a high frequency component, an abnormality of each battery cell is determined.

8. The apparatus for diagnosing abnormality of a battery cell according to claim 7, wherein: The controller is further configured to determine that the voltage distribution in the frequency domain includes a high-frequency component in response to the variance of the current value exceeding a first threshold and the integral value of the absolute value of the current variation exceeding a second threshold within a preset time under a load state.

9. The apparatus for diagnosing abnormality of a battery cell according to claim 7, wherein: The controller is further configured to: in response to a variance of the current value exceeding a first threshold value in a load state within a preset time, determine that the voltage distribution in the frequency domain includes a high-frequency component.

10. The apparatus for diagnosing abnormality of a battery cell according to claim 7, wherein: The controller is further configured to determine that the voltage distribution in the frequency domain includes a high-frequency component in response to an integral value of an absolute value of a current variation under load within a preset time exceeding a second threshold.

11. A method for diagnosing an abnormality of a battery cell, the method comprising: In response to a vehicle including a plurality of battery cells traveling, generating, by a controller, a voltage distribution of each battery cell; The controller converts the voltage distribution of each battery cell from the time domain to the frequency domain; The controller determines the frequency coefficient of each battery cell based on the frequency domain; The abnormality of each battery cell is diagnosed by the controller based on the relative comparison value of the frequency coefficient between the plurality of battery cells.

12. The method according to claim 11, wherein: Diagnosing abnormalities of each battery cell includes: Determining, by the controller, relative comparison values ​​of the frequencies of the respective battery cells; Among the relative comparison values ​​of the respective frequencies, the controller determines that an abnormality has occurred in a battery cell in which a relative comparison value exceeding a threshold value is detected.

13. The method according to claim 11, wherein: Diagnosing abnormalities of each battery cell includes: The controller determines the relative comparison value of each frequency of each battery unit multiple times; Among the relative comparison values ​​of the respective frequencies, the controller determines that an abnormality has occurred in a battery cell in which the relative comparison value detected exceeds a threshold value more than a preset number of times.

14. The method according to claim 11, wherein: Diagnosing abnormalities of each battery cell includes: Each time the vehicle is driven, the controller determines a relative comparison value of each frequency of each battery unit; The controller records, in the relative comparison values ​​of the respective frequencies, the identification number of the battery cell corresponding to the maximum value and the identification number of the battery cell corresponding to the minimum value; The controller determines that a battery cell having an identification number recorded more than a preset number of times among the battery cells has an abnormality.

15. The method according to claim 14, wherein: Diagnosing that a battery cell having an identification number recorded more than a preset number of times has an abnormality includes: in the relative comparison values ​​of the respective frequencies, the controller determines that a battery cell having a maximum value detected more than a preset number of times has an abnormality.

16. The method according to claim 14, wherein: Diagnosing that a battery cell having an identification number recorded more than a preset number of times has an abnormality includes: in the relative comparison values ​​of the respective frequencies, the controller determines that a battery cell having a minimum value detected more than a preset number of times has an abnormality.

17. The method according to claim 11, wherein: Generating the voltage distribution of each battery cell further includes: In response to vehicle travel, a controller generates a current profile for each battery cell; Determining by a controller whether a voltage distribution in a frequency domain includes a high-frequency component based on the current distribution; In response to determining that the voltage distribution in the frequency domain includes a high frequency component, an abnormality of each battery cell is determined by the controller.

18. The method according to claim 17, wherein: Determining whether the voltage distribution includes high-frequency components includes: in response to the variance of the current value exceeding a first threshold and the integral value of the absolute value of the current change exceeding a second threshold within a preset time and under a load state, the controller determines that the voltage distribution in the frequency domain includes high-frequency components.

19. The method according to claim 17, wherein: Determining whether the voltage distribution includes high-frequency components includes: in response to a variance of current values ​​exceeding a first threshold value in a preset time and under a load state, determining by a controller that the voltage distribution in the frequency domain includes high-frequency components.

20. The method according to claim 17, wherein: Determining whether the voltage distribution includes high-frequency components includes: in response to the integral value of the absolute value of the current change amount under load within a preset time exceeding a second threshold, the controller determines that the voltage distribution in the frequency domain includes high-frequency components.

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