A method for diagnosing the active region of a battery cell and a server for performing this diagnosis.

Abstract

The present invention provides a method for diagnosing the active region of a battery cell containing a mixed negative electrode and a server for performing the same. The method for diagnosing the active region of a battery cell containing a mixed negative electrode comprising a first component and a second component is disclosed, and a server for performing the same, which includes the steps of: obtaining impedance information about the battery cell by performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed; obtaining information on impedance changes according to frequency based on the impedance information; and diagnosing the active region of the target battery cell based on the impedance change information.

Description

Technical Field

[0001] The present disclosure relates to a method for diagnosing an active region of a battery cell and a server for performing the same.

Background Art

[0002] When designing the negative electrode of a battery cell, mixing the SiO component and the graphite component can improve the energy density of the battery cell compared to the case of manufacturing the negative electrode of the battery cell using only the graphite component. However, when operating a battery cell having a mixed negative electrode, if the depth of use of SiO is excessively biased, problems may occur in the durability of the battery cell. Therefore, various studies are underway to diagnose the situation and the reaction depth of SiO in the designed mixed negative electrode, and to appropriately modify the operation plan of the battery.

[0003] One of the plurality of conventional techniques used for analyzing a battery cell is Electrochemical Impedance Spectroscopy (EIS). This is an analysis method in which an alternating current voltage or an alternating current is applied to a battery cell at various frequencies, the impedance is calculated based on the measured alternating current or alternating current voltage as a result thereof, and this is represented by a Nyquist plot. It has been widely used because the battery cell can be analyzed non-destructively.

[0004] One of the conventional techniques used to more easily analyze the results of such EIS is the Distribution of Relaxation Times (DRT). This is widely used because it does not require prior knowledge of the impedance of the battery and can identify the equivalent circuit of the battery by converting the impedance data calculated as a result of EIS into a distribution with respect to the relaxation time.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The disclosed embodiments provide a method for diagnosing the active region of a battery cell containing a mixed anode and a server for performing this diagnosis. Specifically, one objective is to provide a method that can rapidly diagnose which battery cell charge state value a particular component in the mixed anode is predominantly activated by analyzing the impedance resistance value due to changes in the charge state value of the battery cell through EIS analysis.

[0006] The technical problems that this embodiment aims to solve are not limited to those described above, and other technical problems can be inferred from the following embodiments. [Means for solving the problem]

[0007] A method for diagnosing the active region of a battery cell containing a mixed negative electrode of a first component and a second component, performed by a server according to one embodiment, may include the steps of: obtaining impedance information relating to the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed; obtaining frequency-dependent impedance change information based on the impedance information; and diagnosing the active region of the target battery cell based on the impedance change information.

[0008] The step of acquiring the impedance change information includes a step of generating a graph showing the magnitude of the impedance according to the frequency by performing a distribution of relaxation times (DRT) on the impedance information, and the diagnostic step may include a step of diagnosing the active region of the mixed negative electrode based on the graph.

[0009] The step of generating the graph includes a step of generating a graph showing the magnitude of impedance according to the frequency based on the change in the charge state value (SoC) of the target battery cell, and the diagnostic step may include a step of diagnosing the active region of the target battery cell based on a first resistance value from the impedance of the first graph at a first charge state value; a second resistance value from the impedance of the second graph at a second charge state value less than the first charge state value; and a third resistance value from the impedance of the third graph at a third charge state value less than the second charge state value.

[0010] The diagnostic steps may include: calculating a first ratio of the first resistance to the second resistance; calculating a second ratio of the second resistance to the third resistance; calculating a third ratio which is the ratio of the second ratio to the first ratio; and diagnosing that, if the third ratio is greater than or equal to a predetermined critical value, the dominant active region of the first component of the mixed negative electrode is in a first charge state.

[0011] The diagnostic steps may include: calculating a first ratio of the first resistance to the second resistance; calculating a second ratio of the second resistance to the third resistance; calculating a third ratio which is the ratio of the second ratio to the first ratio; and diagnosing that, if the third ratio is less than a predetermined critical value, the dominant active region of the second component of the mixed negative electrode is in a first charge state, a second charge state, and a third charge state.

[0012] The first resistance value may be obtained based on the value obtained by integrating the first graph according to the frequency, the second resistance value may be obtained based on the value obtained by integrating the second graph according to the frequency, and the third resistance value may be obtained based on the value obtained by integrating the third graph according to the frequency.

[0013] The step of obtaining impedance change information according to the frequency includes a step of obtaining impedance change information according to the frequency by performing a Nyquist plot analysis on the impedance information, and the Nyquist plot analysis may be performed on at least one of the frequency intervals selected based on user input or arbitrarily selected frequency intervals.

[0014] The first component may be an SiO component, and the second component may be a graphite component.

[0015] The step of acquiring the impedance information may include a step of acquiring impedance information relating to the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell at a predetermined temperature or higher.

[0016] A server for a method of diagnosing the active region of a battery cell according to one embodiment includes a memory for storing instructions and a processor connected to the memory, wherein the processor may be configured to perform electrochemical impedance spectroscopy on the target battery cell to be diagnosed to obtain impedance information relating to the target battery cell from a battery management device, obtain frequency-dependent impedance change information based on the impedance information, and diagnose the active region of the target battery cell based on the impedance change information.

[0017] Specific details of other embodiments are included in the detailed description and drawings. [Effects of the Invention]

[0018] According to the proposed embodiment, one or more of the following effects can be expected:

[0019] In the case of the embodiments of this specification, impedance information corresponding to the change in frequency can be obtained based on the EIS and DRT results of the target battery cell including the hybrid anode.

[0020] Also, in the case of the embodiments of this specification, based on the Nyquist plot analysis result based on the impedance information of the target battery cell including the hybrid anode, impedance information corresponding to the change in frequency can be obtained.

[0021] Also, in the case of the embodiments of this specification, the battery charge state value at which each component constituting the hybrid anode of the target battery cell is dominantly activated is obtained, and considering the degradation rate in the process of charging and discharging the battery cell, it can be used to fabricate a battery cell with improved durability.

[0022] The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Brief Description of the Drawings

[0023] [Figure 1] Shows the interlocking relationship of a server for diagnosing the active region of a battery cell according to an embodiment. [Figure 2] It is a drawing for explaining electrochemical impedance spectroscopy (EIS). [Figure 3] It is a flowchart for explaining a method for diagnosing the active region of a battery cell according to an embodiment. [Figure 4a] Illustrates an example of impedance information. [Figure 4b] Illustrates an example of DRT information obtained by calculating DRT for impedance information. [Figure 5] It is a drawing for explaining the DRT information analysis process in a method for diagnosing the active region of a battery cell according to an embodiment. [Figure 6] It is a drawing for explaining the Nyquist plot analysis process in a method for diagnosing the active region of a battery cell according to an embodiment. [Figure 7] This is a block diagram showing the configuration of a server for diagnosing the active region of a battery cell according to one embodiment. [Modes for carrying out the invention]

[0024] The terminology used in the embodiments has been selected to the greatest extent possible from commonly used terms, taking into account the function described herein, although this may change depending on the intent of the articulators, case law, the emergence of new technologies, etc. In certain cases, the applicant may have arbitrarily selected some terms, in which case their meaning will be described in detail in the relevant explanatory section. Therefore, the terminology used in this disclosure must be defined not merely as names of terms, but based on the meaning of the term and the overall content of this disclosure.

[0025] When a part of the specification is said to "include" a certain component, unless otherwise stated, this means that it may include other components rather than excluding them.

[0026] The expression “at least one of a, b, and c” as described throughout the specification may encompass “a alone,” “b alone,” “c alone,” “a and b,” “a and c,” “b and c,” or “all of a, b, and c.”

[0027] The term "terminal" as used below can be embodied in computers or portable terminals that can connect to servers or other terminals via a network. Here, computers include, for example, laptops, desktops, and laptops equipped with a web browser, and portable terminals can include, for example, all types of handheld-based wireless communication devices that guarantee portability and mobility, such as communication infrastructure terminals for IMT (International Mobile Telecommunication), CDMA (Code Division Multiple Access), W-CDMA (W-Code Division Multiple Access), and LTE (Long Term Evolution), as well as smartphones and tablet PCs.

[0028] The embodiments of this disclosure will be described below in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which this disclosure pertains. However, this disclosure may be embodied in several different forms and is not limited to the embodiments described herein.

[0029] Embodiments of this disclosure will be described in detail below with reference to the drawings.

[0030] Figure 1 shows the interoperability of a server that diagnoses the active region of a battery cell according to one embodiment.

[0031] Referring to Figure 1, the system can operate in conjunction with a battery management device 200 that manages the battery cell 300. In this case, the battery cell 300 may correspond to a target battery cell that includes a mixed negative electrode in which a first component and a second component are mixed. On the other hand, only the components relating to this embodiment are illustrated in Figure 1. Therefore, a person with ordinary skill in the art relating to this embodiment will understand that other general-purpose components may be included in addition to the components illustrated in Figure 1.

[0032] Server 100 is a device that configures and provides diverse information. Server 100 can provide the configured information as a web page or application screen, or as information that can be displayed as a web page or application screen on the receiving terminal.

[0033] The battery management device 200 may include one or more sensors for measuring parameters such as current, voltage, and temperature of the battery cells 300, including the target battery cell to be diagnosed as described above, and may include memory and a processor (not shown) for diverse operations. That is, such a battery management device 200 operates based on memory and a processor, similar to the server 100, but additionally includes sensors that can measure and calculate the parameters of the battery cells 300. According to one embodiment, the battery management device 200 can perform electrochemical impedance spectroscopy (EIS) by applying an external AC power source, i.e., AC voltage or AC current, to the battery cells 300 at various frequencies and measuring the resulting current or voltage. Furthermore, by continuously performing such EIS based on changes in the charge state value (SoC) of the battery cells 300, the battery management device 200 can obtain diverse impedance information of the battery cells 300 according to the frequency.

[0034] Here, the server 100 and the battery management device 200 may be completely separate and independent objects, but they may also exist conceptually only separately within a single device or system. That is, a single computing device equipped with control functions for battery cells may perform all the functions of the server 100 and the battery management device 200 described below, and such embodiments are also considered to fall within the scope of this disclosure.

[0035] Figure 2 is a diagram illustrating electrochemical impedance spectroscopy (EIS).

[0036] Referring to Figure 2, we can see the concept of impedance spectroscopy used to obtain impedance information regarding the lifespan of battery cells. Impedance spectroscopy is a method of analyzing a Nyquist plot obtained by continuously changing the frequency 210 of an AC power supply and applying it to a target battery cell, and separating the impedance information into a real component 220 and an imaginary component 230.

[0037] In impedance spectroscopy, analyzing the electrochemical process of the Nyquist plot with respect to the impedance analysis of a target battery cell involves analyzing four main regions on the Nyquist plot. For example, region 240, which is the axis intercept showing the real component 220 of the impedance information, can be used to analyze impedance information related to the electrolyte ion conductivity characteristics of the electrolyte resistance of the target battery cell and the characteristics of the external electrolyte resistance. For example, the first semicircular region 250 of the impedance information obtained by changing the frequency value 210 can be used to analyze charge transfer impedance information in the solid electrolyte interphase (SEI) generated at the internal electrode particle surface / interface with respect to the solid electrolyte interphase (SEI), thereby analyzing the solid electrolyte interphase resistance (R) of the target battery cell. SEI Information regarding ) can be obtained. For example, the second semicircular region 260 of the impedance information obtained by changing the frequency value 210 is the charge transfer resistance (R), which is a phenomenon that appears when charge moves from the electrode surface / interface of the target battery cell. CTThis can be used to analyze charge transfer impedance information indicating lithium ion oxidation-reduction reactions at electrode material interfaces, thereby obtaining information about the charge transfer resistance of the target battery cell. For example, the linear region 270 obtained by changing the frequency 210 value can include Warburg impedance information obtained in the low frequency region, and can be used to analyze the diffusion phenomenon of lithium ions (Li ions) related to the chemical diffusion resistance of lithium ions due to interlayer insertion into the particle crystal structure within the target battery cell.

[0038] The server 100 according to this disclosure can diagnose the active region in which the components contained in the mixed negative electrode of the battery cell are predominantly activated by performing a Distribution of Relaxation Times (DRT) on the impedance information obtained by changing the frequency 210 value acquired as described above, and obtaining a graph. Furthermore, the server 100 can perform a Nyquist plot analysis on the impedance information and analyze the difference in resistance values ​​according to the frequency value to diagnose the active region in which the components contained in the mixed negative electrode of the battery cell are predominantly activated.

[0039] Figure 3 is a flowchart illustrating a method for diagnosing the active region of a battery cell according to one embodiment.

[0040] Referring to Figure 3, in step 310, the server 100 performing a method for diagnosing the active region of a battery cell according to one embodiment can obtain impedance information about the battery cell by performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed. In this case, the server 100 can obtain information about the battery cell 300 from the battery management device 200. In this case, the battery cell may include a mixed negative electrode in which a first component and a second component are mixed. For example, the first component may be at least one of SiO, SiC, and Si components, and the second component may be graphite. The server 100 can obtain impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell at a predetermined temperature (e.g., 25°C) or higher. In this disclosure, EIS analysis or EIS measurement may mean the process of performing electrochemical impedance spectroscopy on a battery cell, and EIS data or EIS values ​​may mean information indicating the impedance value of the battery cell according to the frequency.

[0041] In step 320, a server 100 according to one embodiment can acquire impedance change information corresponding to frequency based on impedance information. The server 100 can acquire impedance change information by generating a graph showing the magnitude of impedance according to frequency by performing a Distribution of Relaxation Times (DRT) on the impedance information. In this case, DRT may mean a method for analyzing impedance information acquired through the execution of EIS, which does not limit the specific circuit model corresponding to the impedance information in question, and after assuming that a large number of RC circuits exist in series, it may mean an analysis method that shows impedance magnitude information according to frequency based on the assumption that each RC circuit corresponds to a specific frequency. That is, the graph showing the magnitude of impedance in this case may correspond to a graph showing impedance magnitude information by log-scaled frequency. In this disclosure, DRT analysis may mean an analysis technique for confirming the impedance value corresponding to each frequency for EIS data, and the DRT analysis result or DRT information may mean a graph showing the magnitude of impedance by frequency. Furthermore, in step 320, the server 100 according to one embodiment can obtain information on the change in impedance according to frequency by performing Nyquist plot analysis on the impedance information, and the plot analysis may be performed on at least one of the frequency intervals selected based on user input or arbitrarily selected frequency intervals.

[0042] In step 330, the server 100 according to one embodiment can diagnose the active region of the target battery cell based on impedance change information. The server 100 generates a graph showing the magnitude of impedance according to frequency by performing DRT on the impedance information in the previous step 320, and in step 330, it can diagnose the active region of the target battery cell by diagnosing the active region of the mixed anode based on the graph, which will be specifically examined in Figure 5 below. Furthermore, the server 100 can obtain impedance change information according to frequency by performing Nyquist plot analysis on the impedance information in the previous step 320, and can diagnose the active region of the target battery cell by diagnosing the active region of the mixed anode based on the impedance change information, which will be specifically examined in Figure 6 below.

[0043] Figures 4a and 4b illustrate examples of impedance information and DRT information calculated from it.

[0044] Figures 4a and 4b illustrate examples of impedance information and DRT information calculated from it. Referring to Figure 4a, when EIS is performed on a target battery cell, impedance information can be confirmed by a Nyquist plot, which shows the magnitude of the impedance for each frequency, separated into real and imaginary parts. Furthermore, by calculating DRT based on the Nyquist plot derived as shown in Figure 4a, the magnitude of the impedance for each logarithmically scaled frequency can be derived as DRT information, as shown in Figure 4b.

[0045] The impedance information disclosed herein may mean impedance information that can be represented by a Nyquist plot. The DRT information disclosed herein may be a distribution graph obtained by converting the impedance information into a distribution with respect to relaxation time.

[0046] The following provides a more detailed explanation of each stage.

[0047] First, the server 100 performs EIS on the target battery cell 300, which includes a mixed negative electrode containing a first component and a second component, and can obtain impedance information about the battery cell 300. Here, such impedance information can be obtained from the battery management device 200. As mentioned above, the battery management device 200 can obtain impedance information about the target battery cell by performing EIS on the target battery cell at a temperature above a predetermined temperature.

[0048] Subsequently, the server 100 can generate a graph showing the magnitude of impedance according to frequency by calculating DRT on the impedance information thus acquired. Subsequently, the server 100 can generate multiple graphs showing the magnitude of impedance according to frequency while changing the charge state value of the target battery cell. The server 100 can calculate the impedance resistance value of each graph and determine that the charge state in the interval where the ratio of each resistance value changes rapidly and exceeds a predetermined critical value is the dominant active region of the first component. Conversely, the server 100 can calculate the impedance resistance value and determine that if there is no significant change in the ratio of each resistance value in a particular charge state interval, that charge state interval is the dominant active region of the second component.

[0049] Server 100 can also perform Nyquist board plot analysis on the same impedance information while changing the charge state of the battery cell, without performing DRT, and obtain impedance change information. Server 100 can obtain the difference in resistance values ​​in a specific frequency interval at a specific charge state of the battery cell and compare the difference in resistance values ​​in a specific frequency interval at multiple charge states of the battery cell. If the change in the mentioned difference in resistance values ​​at a specific charge state is significant as a result of the comparison, Server 100 can diagnose the relevant charge region as the dominant active region of the first component, based on user input.

[0050] Figure 5 is a diagram illustrating the DRT information analysis process in a method for diagnosing the active region of a battery cell according to one embodiment.

[0051] Referring to Figure 5, a server 100 according to one embodiment can generate a graph showing the magnitude of impedance according to frequency based on changes in the charge state value (SoC) of the target battery cell, and can diagnose the active region of the target battery cell based on the first resistance value of the impedance in the first graph at the first charge state value, the second resistance value of the impedance in the second graph at the second charge state value which is less than the first charge state value, and the third resistance value of the impedance in the third graph at the third charge state value which is less than the second charge state value. In this case, a change in the charge state value of the target battery cell may mean, for example, a change in the charge state value which continuously decreases or continuously increases between 0% and 100%. For example, assuming that the server 100 generates a frequency-dependent graph due to a change in the charge state value of the target battery cell which continuously decreases, the server 100 can diagnose the active region of the target battery cell based on the first frequency value 510-1 (e.g., 10 5 From Hz) to the second frequency value 510-2 (e.g., 10 2 The server 100 can generate a first graph 520-1 showing the magnitude of impedance as the frequency changes (Hz), and a second graph 520-2 showing the magnitude of impedance as the frequency changes from the first frequency 510-1 to the second frequency 510-2 at a second charge state value which is less than the first charge state value. Furthermore, the server 100 can generate a third graph 520-3 showing the magnitude of impedance as the frequency changes from the first frequency 510-1 to the second frequency 510-2 at a third charge state value which is less than the second charge state value.

[0052] In one embodiment, the server 100 can diagnose the active region of a target battery cell based on a first resistance value of the impedance of the first graph 520-1 at a first charge state value, a second resistance value of the impedance of the second graph 520-2 at a second charge state value less than the first charge state value, and a third resistance value of the impedance of the third graph 520-3 at a third charge state value less than the second charge state value. In this case, the first resistance value may be obtained based on a value 530-1 obtained by integrating the first graph 520-1 with respect to frequency, the second resistance value may be obtained based on a value 530-2 obtained by integrating the second graph 520-2 with respect to frequency, and the third resistance value may be obtained based on a value 530-3 obtained by integrating the third graph 520-3 with respect to frequency.

[0053] Server 100 can calculate the first ratio of the first resistance to the second resistance and the second ratio of the second resistance to the third resistance. Server 100 can also calculate the third ratio, which is the ratio of the second ratio to the first ratio. Furthermore, if the third ratio is greater than or equal to a predetermined critical value (e.g., 2), Server 100 can diagnose that the dominant active region of the first component of the mixed negative electrode is in the first charge state. For example, Server 100 can calculate the first, second, and third ratios using the following mathematical formula 1.

[0054]

number

[0055] In this case, R1 to R3 can represent the first resistance value to the third resistance value, respectively, and r1 to r3 can represent the first ratio to the third ratio. As can be seen in Figure 5, by comparing the areas of the values ​​obtained by integrating the third graph 520-3 with respect to frequency (530-3) and the second graph 520-2 with respect to frequency (530-2), the difference between the third resistance value and the second resistance value is not large, so the second ratio in this case can be considered to be approximately close to 1. However, comparing the areas of the values ​​obtained by integrating the second graph 520-2 with respect to frequency (530-2) and the first graph 520-1 with respect to frequency (530-1), it can be seen that the first resistance value is about half the size of the second resistance value, so the first ratio in this case can be considered to be approximately close to 0.5. Thus, the third ratio, which is the ratio of the second ratio to the first ratio, can be considered to be approximately close to a predetermined critical value of 2 or more. In other words, as the charge state value of the target battery cell changes and the charge state value continues to decrease, the server 100 generates a first graph 520-1, a second graph 520-2, and a third graph 520-3 corresponding to the frequency, and can compare the first resistance value to the third resistance value based on the value obtained by integrating each graph according to the frequency. When the first ratio, which represents the ratio of the first resistance value to the second resistance value, shows a significant difference in value compared to the second ratio, which represents the ratio of the second resistance value to the third resistance value, the third ratio will have a value greater than or equal to a predetermined critical value (e.g., 1.5), and the server 100 can determine that the first resistance value at the first charge state has changed rapidly compared to the third resistance value at the third charge state value and the second resistance value at the second charge state value. As a result, the server 100 can diagnose that the dominant active region of the first component of the mixed negative electrode is the first charge state.

[0056] Even if the charge state value is not the same as the first to third charge state values ​​mentioned, the server 100 can generate the first graph 520-1 to the third graph 520-3, as described in Figure 5, by any change in the charge state value. Also, as described, the server 100 can calculate the first ratio, the second ratio, and the third ratio based on the first resistance value, the second resistance value, and the third resistance value. Unlike what was described using Figure 5 as a reference, if the third ratio falls below a predetermined critical value, the server 100 can determine that there has been no significant change in the first resistance value in the first charge state value, similar to the third resistance value in the third charge state value and the second resistance value in the second charge state value. In this case, the third ratio will have a value less than a predetermined critical value, and the server 100 can diagnose that the dominant active region of the second component of the mixed negative electrode is in the first charge state, the second charge state, and the third charge state.

[0057] Figure 6 is a diagram illustrating the Nyquist plot analysis process in a method for diagnosing the active region of a battery cell according to one embodiment.

[0058] Referring to Figure 6, a server 100 according to one embodiment can obtain information on the change in impedance according to frequency by performing a Nyquist plot analysis on the impedance information as examined in Figures 2 and 4a. In this case, the plot analysis may be performed on at least one of the frequency intervals selected based on user input or arbitrarily selected by the server. For example, the server 100 may perform a frequency interval selected based on user input (e.g., 10 5 Hz to 10 2Within the frequency range of Hz, impedance change information 620-1; 620-2; 620-3 can be obtained according to the battery charge state value. Based on the first frequency value 510-1 and the second frequency value 510-2 explained in Figure 5, the server 100 can diagnose from the respective change information that the battery charge state when the difference between the resistance value at the first frequency value 510-1 and the resistance value at the second frequency value 510-2 changes rapidly corresponds to the charge state in the dominant active region of the first component.

[0059] For example, server 100 can obtain the difference 650-1 between the resistance value 630-1 at the first frequency value 510-1 and the resistance value 640-1 at the second frequency value 510-2 from the impedance change information 620-1 at the first charge state value. Furthermore, from the change information 620-2 at the second charge state value which is less than the first charge state value, it can obtain the difference 650-2 between the resistance value 630-2 at the first frequency value 510-1 and the resistance value 640-2 at the second frequency value 510-2, and from the change information 620-3 at the third charge state value which is less than the second charge state value, it can obtain the difference 650-3 between the resistance value 630-3 at the first frequency value 510-1 and the resistance value 640-3 at the second frequency value 510-2.

[0060] As can be seen in Figure 6, when the charge state value of the battery cell changes from a first charge state value to a third charge state value in a sustained decrease, and the difference 650-1 in the first charge state value is determined to be greater than or equal to a critical value compared to the difference 650-2 in the second charge state value and the difference 650-3 in the third charge state value, the server 100 can diagnose, based on the input regarding the active region diagnosis received from the user terminal (not shown), that the first charge state corresponds to a charge state in which the first component of the mixed negative electrode is dominant.

[0061] The explanation of the method for diagnosing the active region of a battery cell according to this disclosure in Figures 5 and 6 was based on a change in the battery cell's charge state value that is continuously decreasing, with respect to a first charge state value, a second charge state value less than the first charge state value, and a third charge state value less than the second charge state value. However, it is obvious that a change in the battery cell's charge state value that is continuously increasing also falls under one embodiment of the method for diagnosing the active region of a battery cell according to this disclosure.

[0062] Figure 7 shows a block diagram of a server according to one embodiment.

[0063] In one embodiment, the server 100 may include memory 101 and a processor 102. The server 100 shown in Figure 7 only illustrates the components relating to this embodiment. Therefore, a person with ordinary skill in the art relating to this embodiment will understand that other general components may be included in addition to the components shown in Figure 7. In one embodiment, the processor 102 may be included in a controller.

[0064] The processor 102 can control the overall operation of the server 100 and process data and signals. The processor 102 may consist of at least one hardware unit. The processor 102 can also be operated by one or more software modules generated by executing program code stored in memory 101. Because the processor 102 can include memory, it can execute program code stored in memory to control the overall operation of the server 100 and process data and signals.

[0065] The processor 102 may be configured to perform electrochemical impedance spectroscopy on the target battery cell to be diagnosed in order to acquire impedance information about the battery cell, acquire information on impedance changes according to frequency based on the impedance information, and diagnose the active region of the target battery cell based on the impedance change information.

[0066] Depending on the embodiment, the server 100 may additionally include a transceiver for wired / wireless communication. The server 100 can communicate with an external electronic device (e.g., a battery management device 200) using the transceiver. The external electronic device may be a terminal or a server. The communication technologies used by the transceiver include GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), LTE (Long Term Evolution), 5G, WLAN (Wireless LAN), Wi-Fi (Wireless-Fidelity), and Bluetooth®. TM Possible technologies include RFID (Radio Frequency Identification), infrared communication (Infrared Data Association; IrDA), ZigBee, and NFC (Near Field Communication).

[0067] The server according to the above embodiment may include a processor, memory for storing and executing program data, permanent storage such as a disk drive, communication ports for communicating with external devices, and user interface devices such as a touch panel, keys, and buttons. A method embodied in a software module or algorithm may be stored on a computer-readable recording medium as computer-readable code or program instructions executable on the processor. Here, computer-readable recording media include magnetic recording media (e.g., ROM (read-only memory), RAM (random-access memory), floppy disks, hard disks, etc.) and optically readable media (e.g., CD-ROM, DVD (Digital Versatile Disc), etc.). Computer-readable recording media may be distributed across a network of computer systems, and computer-readable code may be stored and executed in a distributed manner. The medium may be computer-readable, stored in memory, and executed on the processor.

[0068] This embodiment may be represented by functional block configurations and diverse processing stages. Such functional blocks may be embodied by a variety of hardware and / or software configurations that perform specific functions. For example, the embodiment may employ direct circuit configurations such as memory, processing, logic, and look-up tables, which can perform diverse functions under the control of one or more microprocessors or other control devices. Just as the components may be executed by software programming or software elements, this embodiment includes a variety of algorithms embodied by combinations of data structures, processes, routines, or other programming configurations, which may be embodied in programming or scripting languages ​​such as C, C++, Java, and assembler. Functional aspects may be embodied by algorithms executed on one or more processors. Furthermore, this embodiment may employ prior art for electronic environment configuration, signal processing, and / or data processing. Terms such as “mechanism,” “element,” “means,” and “configuration” may be used broadly and are not limited to mechanical and physical configurations. The terms may also include the meaning of a series of software processes (routines) in conjunction with a processor, etc.

[0069] The embodiments described above are merely illustrative examples, and other embodiments may be embodied within the scope of the claims described later. [Explanation of Symbols]

[0070] 100 servers 101 memory 102 Processors 200 Battery management device 300 battery cells

Claims

1. In a method for diagnosing the active region of a battery cell containing a mixed negative electrode in which a first component and a second component are mixed, performed on a server, The steps include: obtaining impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed; A step of obtaining information on the change in impedance according to frequency based on the aforementioned impedance information, The step includes diagnosing the active region of the target battery cell based on the impedance change information, A method for diagnosing the active region of a battery cell.

2. The step of acquiring the impedance change information is as follows: The process includes a step of performing a relaxation time distribution (DRT) on the impedance information to generate a graph showing the magnitude of the impedance according to the frequency, The aforementioned diagnostic stage is, The step includes diagnosing the active region of the mixed negative electrode based on the graph, A method for diagnosing the active region of a battery cell according to claim 1.

3. The step of generating the aforementioned graph is: The process includes a step of generating a graph showing the magnitude of the impedance corresponding to the frequency based on the change in the charge state value (SoC) of the target battery cell. The aforementioned diagnostic stage is, The process includes a step of diagnosing the active region of the target battery cell based on a first resistance value from the impedance of a first graph at a first charge state value, a second resistance value from the impedance of a second graph at a second charge state value less than the first charge state value, and a third resistance value from the impedance of a third graph at a third charge state value less than the second charge state value. A method for diagnosing the active region of a battery cell according to claim 2.

4. The aforementioned diagnostic stage is, A step of calculating a first ratio of the first resistance value to the second resistance value, A step of calculating the second ratio of the second resistance value to the third resistance value, A step of calculating a third ratio, which is the ratio of the second ratio to the first ratio, The process includes the step of diagnosing that the dominant active region of the first component of the mixed negative electrode is in a first charge state if the third ratio is greater than or equal to a predetermined critical value, A method for diagnosing the active region of a battery cell according to claim 3.

5. The aforementioned diagnostic stage is, A step of calculating a first ratio of the first resistance value to the second resistance value, A step of calculating the second ratio of the second resistance value to the third resistance value, A step of calculating a third ratio which is the ratio of the second ratio to the first ratio, The procedure includes the step of diagnosing that, if the third ratio is less than a predetermined critical value, the dominant active region of the second component of the mixed negative electrode is in a first charge state, a second charge state, and a third charge state. A method for diagnosing the active region of a battery cell according to claim 3.

6. The first resistance value is obtained based on the value obtained by integrating the first graph according to the frequency, the second resistance value is obtained based on the value obtained by integrating the second graph according to the frequency, and the third resistance value is obtained based on the value obtained by integrating the third graph according to the frequency. A method for diagnosing the active region of a battery cell according to claim 3.

7. The step of obtaining information on the change in impedance corresponding to the aforementioned frequency is: This includes a step of obtaining information on the change in impedance according to frequency by performing a Nyquist plot analysis on the aforementioned impedance information. The Nyquist plot analysis described above is performed on at least one of the frequency intervals selected based on user input or arbitrarily selected frequency intervals. A method for diagnosing the active region of a battery cell according to claim 1.

8. The first component is the SiO component, The second component is a graphite component. A method for diagnosing the active region of a battery cell according to claim 1.

9. The step of acquiring the aforementioned impedance information is: The process includes a step of obtaining impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell at a predetermined temperature or above. A method for diagnosing the active region of a battery cell according to claim 1.

10. A computer-readable non-temporary recording medium that stores a program for causing a server to execute the method according to any one of claims 1 to 9.

11. On the server, Memory for storing instructions, A processor connected to the memory, The aforementioned processor, By performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed, impedance information related to the target battery cell is obtained from the battery management device. Based on the aforementioned impedance information, information on the change in impedance according to frequency is obtained, Based on the impedance change information, the system is configured to diagnose the active region of the target battery cell. server.

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