Server, and method for diagnosing active area of battery cell

Abstract

Disclosed are a method for diagnosing, by a server, an active area of a battery cell including a mixed negative electrode in which a first component and a second component are mixed, and the server. This method comprises the steps of: acquiring impedance information of a target battery cell to be diagnosed, by performing electrochemical impedance spectroscopy on the battery cell; acquiring, on the basis of the impedance information, information about a change in impedance according to a frequency; and diagnosing an active area of the target battery cell on the basis of the information about the change in impedance.

Description

How to diagnose the active area of ​​servers and battery cells

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

[0002]

[0003] When designing a battery cell's cathode, mixing SiO and graphite components can improve the energy density of the battery cell compared to using only graphite. However, excessive concentration of SiO in the cathode can lead to durability issues in battery cells with mixed cathodes. Therefore, various studies are being conducted to diagnose the reaction depth and conditions of SiO in designed mixed cathodes and to adjust them appropriately for battery operation.

[0004] One of the many conventional techniques used to analyze battery cells is electrochemical impedance spectroscopy (EIS). This analytical method applies alternating voltage or current at various frequencies to a battery cell, calculates impedance based on the resulting measured current or voltage, and expresses this as a Nyquist plot. It has been widely used for non-destructive analysis of battery cells.

[0005] One conventional technique used to facilitate the analysis of EIS results is the Distribution of Relaxation Times (DRT). This technique is widely used because it converts impedance data calculated from EIS results into a relaxation time distribution, enabling the identification of the battery's equivalent circuit without requiring prior knowledge of the battery's impedance.

[0006]

[0007] The disclosed embodiments provide a method for diagnosing an active area of ​​a battery cell including a mixed cathode and a server for performing the same. Specifically, the purpose is to provide a method for rapidly diagnosing which specific component included in a mixed cathode is dominantly activated at which state of charge of a battery cell by analyzing the resistance value of impedance according to changes in the state of charge of the battery cell through EIS analysis.

[0008] The technical tasks to be achieved by this embodiment are not limited to the technical tasks described above, and other technical tasks can be inferred from the following embodiments.

[0009]

[0010] A method for diagnosing an active area of ​​a battery cell including a mixed cathode in which a first component and a second component are mixed, performed on a server according to one embodiment, may include the steps of: performing electrochemical impedance spectroscopy on a target battery cell to be diagnosed, thereby obtaining impedance information about the battery cell; obtaining impedance change information according to frequency based on the impedance information; and diagnosing an active area of ​​the target battery cell based on the impedance change information.

[0011] The step of obtaining the impedance change information may include a step of generating a graph representing the magnitude of the impedance according to the frequency by performing a distribution of relaxation times (DRT) on the impedance information, and the diagnosing step may include a step of diagnosing the active area of ​​the mixed cathode based on the graph.

[0012] The step of generating the graph may include a step of generating graphs representing the magnitude of the impedance according to the frequency according to a change in the state of charge (SoC) value of the target battery cell, and the step of diagnosing may include a step of diagnosing the active area of ​​the target battery cell based on a first resistance value of the impedance of a first graph at a first state of charge value; a second resistance value of the impedance of a second graph at a second state of charge value that is less than the first state of charge value; and a third resistance value of the impedance of a third graph at a third state of charge value that is less than the second state of charge value.

[0013] The diagnosing step may include: calculating a first ratio of the first resistance value to the second resistance value; calculating a second ratio of the second resistance value to the third resistance value; calculating a third ratio which is a ratio of the second ratio to the first ratio; and diagnosing that a dominant active region of the first component of the mixed negative electrode is in a first charge state when the third ratio is equal to or greater than a predetermined threshold.

[0014] The diagnosing step may include: calculating a first ratio of the first resistance value to the second resistance value; calculating a second ratio of the second resistance value to the third resistance value; calculating a third ratio which is a ratio of the second ratio to the first ratio; and diagnosing, when the third ratio is less than a predetermined threshold, that the predominant 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.

[0015] The first resistance value may be obtained based on a value obtained by integrating the first graph according to the frequency, the second resistance value may be obtained based on a value obtained by integrating the second graph according to the frequency, and the third resistance value may be obtained based on a value obtained by integrating the third graph according to the frequency.

[0016] The step of obtaining information on impedance change according to the frequency includes a step of obtaining information on impedance change according to the frequency by performing Nyquist plot analysis on the impedance information, and the plot analysis may be performed on at least one of a frequency section selected based on a user input or a randomly selected frequency section.

[0017] The first component may be a SiO component, and the second component may be a graphite component.

[0018] The obtaining step may include obtaining impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell at a predefined temperature or higher.

[0019] A method for diagnosing an active area of ​​a battery cell according to one embodiment of the present invention comprises: a memory storing a command; and a processor connected to the memory, wherein the processor is configured to perform electrochemical impedance spectroscopy on a target battery cell to be diagnosed, thereby obtaining impedance information about the battery cell from a battery management device, obtaining impedance change information according to frequency based on the impedance information, and diagnosing an active area of ​​the target battery cell based on the impedance change information.

[0020] Specific details of other embodiments are included in the detailed description and drawings.

[0021]

[0022] According to the proposed embodiment, one or more of the following effects can be expected.

[0023] According to an embodiment of the present specification, impedance information according to frequency change can be obtained based on EIS and DRT results of a target battery cell including a mixed cathode.

[0024] In addition, according to an embodiment of the present specification, impedance information according to frequency change can be obtained based on the results of a Nyquist board plot analysis based on impedance information of a target battery cell including a mixed negative electrode.

[0025] In addition, according to the embodiment of the present specification, it is possible to obtain a battery state of charge value in which each component constituting the mixed negative electrode of the target battery cell is predominantly activated, and to manufacture a battery cell with improved durability by considering the degradation rate during the charging and discharging process of the battery cell.

[0026] 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.

[0027]

[0028] Figure 1 illustrates the interconnection relationship of a server that diagnoses an active area of ​​a battery cell according to one embodiment.

[0029] Figure 2 is a diagram for explaining electrochemical impedance spectroscopy (EIS).

[0030] FIG. 3 is a flowchart illustrating a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0031] Figures 4a and 4b illustrate an example of impedance information and DRT information obtained by calculating DRT for the impedance information.

[0032] FIG. 5 is a diagram for explaining a DRT information analysis process in a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0033] FIG. 6 is a diagram for explaining a Nyquist plot analysis process in a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0034] FIG. 7 is a block diagram showing the configuration of a server for diagnosing an active area of ​​a battery cell according to one embodiment.

[0035]

[0036] The terms used in the embodiments have been selected from widely used and common terms, taking into account the functions of the present disclosure. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, in which case their meanings will be described in detail in the relevant description. Therefore, the terms used in this disclosure should not be defined simply as names of terms, but rather based on the meanings of the terms and the overall content of the present disclosure.

[0037] When a part of a specification is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0038] The expression "at least one of a, b, and c" 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'.

[0039] The "terminal" mentioned below may be implemented as a computer or portable terminal that can connect to a server or other terminal via a network. Here, the computer includes, for example, a notebook, desktop, laptop, etc. equipped with a web browser, and the portable terminal may include, for example, a wireless communication device that guarantees portability and mobility, and may include all types of handheld-based wireless communication devices such as communication-based terminals such as IMT (International Mobile Telecommunication), CDMA (Code Division Multiple Access), W-CDMA (W-Code Division Multiple Access), LTE (Long Term Evolution), smartphones, tablet PCs, etc.

[0040] Below, embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0041] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0042]

[0043] Figure 1 illustrates the interconnection relationship of a server that diagnoses an active area of ​​a battery cell according to one embodiment.

[0044] Referring to FIG. 1, the system may operate in conjunction with a battery management device (200) that manages a battery cell (300). In this case, the battery cell (300) may correspond to a target battery cell including a mixed negative electrode in which the first component and the second component are mixed. Meanwhile, FIG. 1 only illustrates components related to the present embodiment. Therefore, those skilled in the art related to the present embodiment will understand that, in addition to the components illustrated in FIG. 1, other general-purpose components may be included.

[0045] The server (100) is a device that configures and provides various information. The server (100) may provide the configured information as a web page or application screen, or may provide the information in a form that can be displayed as a web page or application screen on a receiving terminal.

[0046] The battery management device (200) may include one or more sensors for measuring parameters such as current, voltage, and temperature of the battery cell (300) including the target battery cell to be diagnosed as described above, and may include a memory and a processor (not shown) for various operations. That is, the battery management device (200) operates based on the memory and the processor similarly to the server (100), but may additionally include a sensor to measure and calculate the parameters of the battery cell (300). According to one embodiment, the battery management device (200) may perform electrochemical impedance spectroscopy (EIS) by applying an external AC power source, i.e., an AC voltage or an AC current, to the battery cell (300) at various frequencies and measuring the current or voltage flowing accordingly. In addition, the battery management device (200) can obtain various impedance information of the battery cell (300) according to frequency by continuously performing EIS according to changes in the state of charge value (SoC) of the battery cell (300).

[0047] Here, the server (100) and the battery management device (200) may be completely separate and independent entities, or they may exist only conceptually separated within a single device or system. That is, a single computing device equipped with a control function for battery cells may perform both the functions of the server (100) and the battery management device (200) described below, and therefore, such an embodiment is also considered to fall within the scope of the present disclosure.

[0048]

[0049] Figure 2 is a diagram for explaining electrochemical impedance spectroscopy (EIS).

[0050] Referring to Fig. 2, the concept of impedance spectroscopy used to obtain impedance information related to the lifespan of a battery cell can be confirmed. Impedance spectroscopy refers to a method of interpreting a Nyquist plot obtained by dividing the impedance information obtained by continuously changing the frequency (210) of AC power and applying it to a target battery cell into a real component (220) and an imaginary component (230).

[0051] Interpreting the electrochemical process of the Nyquist plot in relation to the impedance analysis of the target battery cell in impedance spectroscopy involves analyzing four major regions on the Nyquist plot. For example, the region (240), which is the intercept of the axis representing the real component (220) of the impedance information, can be utilized to analyze impedance information related to the characteristics of the electrolyte ionic conductivity 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 (210) value can be utilized to analyze charge transfer impedance information in the SEI generated at the surface / interface of the internal electrode particles in relation to the solid electrolyte interphase (SEI), and thus the solid electrolyte film resistance (SEI) of the target battery cell. ) can be obtained. For example, the second semicircle area (260) of the impedance information obtained by changing the frequency (210) value is the charge transfer resistance (Charge Transfer Resistance), which is a phenomenon that occurs when charges are transferred at the electrode surface / interface of the target battery cell. ) can be utilized to analyze charge transfer impedance information representing lithium ion redox reaction at the electrode material interface, and thus information on charge transfer resistance of the target battery cell can be obtained. For example, the linear region (270) acquired by changing the frequency (210) value can include Warburg impedance information acquired in the low frequency region, and can be utilized 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.

[0052] The server (100) according to the present disclosure can diagnose an active region in which a component included in the mixed negative electrode of a battery cell is predominantly activated by performing a Distribution of Relaxation Times (DRT) on the impedance information obtained by changing the frequency (210) value obtained as described above. In addition, the server (100) can diagnose an active region in which a component included in the mixed negative electrode of a battery cell is predominantly activated by analyzing the difference in resistance value according to the frequency value by performing a Nyquist plot analysis on the impedance information.

[0053]

[0054] FIG. 3 is a flowchart illustrating a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0055] Referring to FIG. 3, in step (310), a server (100) performing a method for diagnosing an active area of ​​a battery cell according to an embodiment may 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) may 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 correspond to at least one of a SiO component, a SiC component, and a Si component, and the second component may be a graphite component. The server (100) may obtain impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell at a predefined temperature (e.g., 25°C) or higher. In the present disclosure, EIS analysis or EIS measurement may mean a process of performing electrochemical impedance spectroscopy on a battery cell, and EIS data or EIS value may mean information indicating an impedance value according to frequency for a battery cell.

[0056] In step (320), the server (100) according to one embodiment can obtain impedance change information according to frequency based on impedance information. The server (100) can obtain impedance change information by generating a graph representing the magnitude of impedance according to frequency by performing Distribution of Relaxation Times (DRT) on the impedance information. In this case, DRT is a method for analyzing impedance information obtained by performing EIS, and may mean an analysis method that does not limit a specific circuit model corresponding to the impedance information, and then assumes that a large number of RC circuits exist in series and then assumes that each RC circuit corresponds to a specific frequency, and then represents impedance magnitude information according to frequency. That is, the graph representing the impedance magnitude in this case may correspond to a graph representing impedance magnitude information by logarithmically scaled frequency. In the present disclosure, DRT analysis may refer to an analysis technique for confirming an impedance value according to each frequency for EIS data, and the DRT analysis result or DRT information may refer to a graph showing the impedance size according to frequency. In addition, in step (320), the server (100) according to one embodiment may obtain information on impedance change according to frequency by performing Nyquist plot analysis on the impedance information, and the plot analysis may be performed on at least one of a frequency section selected based on a user input or a randomly selected frequency section.

[0057] In step (330), the server (100) according to one embodiment can diagnose the active area of ​​the target battery cell based on the impedance change information. The server (100) can diagnose the active area of ​​the target battery cell by generating a graph representing the magnitude of the impedance according to the frequency by performing DRT on the impedance information in the previous step (320), and diagnosing the active area of ​​the mixed negative electrode based on the graph in step (330), which will be described in detail in FIG. 5 below. In addition, the server (100) can diagnose the active area of ​​the target battery cell by obtaining information on impedance change according to the frequency by performing Nyquist plot analysis on the impedance information in the previous step (320), and diagnosing the active area of ​​the mixed negative electrode based on the impedance change information, which will be described in detail in FIG. 6 below.

[0058]

[0059] Figures 4a and 4b illustrate an example of impedance information and DRT information obtained by calculating DRT for the impedance information.

[0060] Figures 4a and 4b illustrate examples of impedance information and DRT information calculated based on the impedance information. Referring to Figure 4a, when EIS is performed on a target battery cell, the impedance information can be confirmed as a Nyquist plot in which the magnitude of the impedance for each frequency is expressed by dividing it into the real and imaginary axes. In addition, when DRT is calculated based on the Nyquist plot derived as in Figure 4a, the magnitude of the impedance for each frequency in a logarithmic scale can be derived as DRT information, as in Figure 4b.

[0061] The impedance information disclosed in this document may refer to impedance information that can be expressed as a Nyquist plot. The DRT information disclosed in this document may be a distribution graph that converts impedance information into a distribution for relaxation times.

[0062] Below, we will explain each step in more detail.

[0063] First, the server (100) can obtain impedance information about the battery cell (300) by performing EIS on the target battery cell (300) including a mixed negative electrode in which the first component and the second component are mixed. Here, such impedance information can be obtained from the battery management device (200). As described 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 higher than a predefined temperature.

[0064] Thereafter, the server (100) can generate a graph indicating the magnitude of impedance according to frequency by calculating the DRT for the impedance information obtained in this manner. Thereafter, the server (100) can generate a plurality of graphs indicating the magnitude of impedance according to frequency by changing the state of charge value of the target battery cell. The server (100) can calculate the resistance values ​​of the impedance of each graph, and determine that the state of charge in a section where the ratio of each resistance value changes rapidly and exceeds a predetermined threshold value is a predominantly active region of the first component. Conversely, the server (100) can calculate the resistance values ​​of the impedance, and if there is no significant change in the ratio of each resistance value in specific state of charge sections, the server (100) can determine that the state of charge sections are predominantly active regions of the second component.

[0065] The server (100) can also perform a Nyquist Bode plot analysis on the same impedance information without performing DRT while changing the state of charge of the battery cell and obtain impedance change information. The server (100) can obtain the difference in resistance values ​​in a specific frequency range in a specific state of charge of the battery cell and compare the differences in resistance values ​​in a specific frequency range in multiple states of charge of the battery cell. If the change in the difference in the resistance values ​​in a specific state of charge is significant as a result of the comparison, the server (100) can diagnose the corresponding charging region as a predominantly active region of the first component based on a user input.

[0066]

[0067] FIG. 5 is a diagram for explaining a DRT information analysis process in a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0068] Referring to FIG. 5, a server (100) according to an embodiment may generate graphs representing the magnitude of impedance according to frequency according to a change in a state of charge (SoC) of a target battery cell, and may diagnose an active area of ​​the target battery cell based on a first resistance value of the impedance of a first graph at a first state of charge value, a second resistance value of the impedance of a second graph at a second state of charge value that is less than the first state of charge value, and a third resistance value of the impedance of a third graph at a third state of charge value that is less than the second state of charge value. In this case, a change in the state of charge of the target battery cell may mean, for example, a change in which the state of charge value continuously decreases or continuously increases between 0% and 100%. For example, assuming that the server (100) generates a graph according to frequency as the state of charge value of the target battery cell continuously decreases, the server (100) generates a graph according to frequency as the frequency value increases from the first state of charge value to the first frequency value (510-1) (e.g., Hz) to the second frequency value (510-2) (e.g. The server (100) can generate a first graph (520-1) representing the magnitude of the impedance as the frequency value changes from the first frequency value (510-1) to the second frequency value (510-2) at a second charging state value that is less than the first charging state value, and can generate a second graph (520-2) representing the magnitude of the impedance as the frequency value changes from the first frequency value (510-1) to the second frequency value (510-2) at a third charging state value that is less than the second charging state value. In addition, the server (100) can generate a third graph (520-3) representing the magnitude of the impedance as the frequency value changes from the first frequency value (510-1) to the second frequency value (510-2) at a third charging state value that is less than the second charging state value.

[0069] According to one embodiment, the server (100) can diagnose the active area of ​​the 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 that is 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 that is less than the second charge state value. In this case, the first resistance value can be obtained based on a value (530-1) obtained by integrating the first graph (520-1) according to frequency, the second resistance value can be obtained based on a value (530-2) obtained by integrating the second graph (520-2) according to frequency, and the third resistance value can be obtained based on a value (530-3) obtained by integrating the third graph (520-3) according to frequency.

[0070] The server (100) can calculate a first ratio of the first resistance value to the second resistance value, and a second ratio of the second resistance value to the third resistance value. In addition, the server (100) can calculate a third ratio, which is the ratio of the second ratio to the first ratio. Furthermore, the server (100) can diagnose that the dominant active region of the first component of the mixed negative electrode is in the first charge state when the third ratio is equal to or greater than a predetermined threshold value (e.g., 2). For example, the server (100) can calculate the first ratio, the second ratio, and the third ratio according to the following mathematical expression 1.

[0071]

[0072]

[0073]

[0074] In this case Inland can mean the first resistance value to the third resistance value, respectively, Inland may mean the first ratio or the third ratio. As can be confirmed by comparing the areas of the integrated value (530-3) of the third graph (520-3) according to frequency and the integrated value (530-2) of the second graph (520-2) according to frequency as shown in Fig. 5, 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, when comparing the areas of the integrated value (530-2) of the second graph (520-2) according to frequency and the integrated value (530-1) of the first graph (520-1) according to frequency, it can be seen that the first resistance value has about half the size of the second resistance value, and the first ratio in this case can be considered to be approximately close to 0.5. Accordingly, the third ratio, which is the ratio of the second ratio to the first ratio, can be seen as being close to a value greater than or equal to a predetermined threshold of 2. That is, the server (100) can generate the first graph (520-1), the second graph (520-2), and the third graph (520-3) according to the frequency as the state of charge value of the target battery cell continuously decreases, and compare the first resistance value to the third resistance value based on the integrated value of each graph according to the frequency. When the first ratio, which means the ratio of the first resistance value to the second resistance value, shows a significant difference in value compared to the second ratio, which means the ratio of the second resistance value to the third resistance value, and the third ratio has a value greater than or equal to a predetermined threshold value (e.g., 1.5), the server (100) can determine that the first resistance value at the first charge state value has changed rapidly compared to the third resistance value at the third charge state value or the second resistance value at the second charge state value. Accordingly, the server (100) can diagnose that the dominant active region of the first component of the mixed negative electrode is the first charge state.

[0075] Even if the charging state values ​​are not the same as the first to third charging state values ​​mentioned, the server (100) can generate the first graph (520-1) to the third graph (520-3) as described in FIG. 5 according to arbitrary changes in the charging state values. In addition, similarly to the description, 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 the description based on FIG. 5, when the third ratio is less than a predetermined threshold, the server (100) can determine that there has been no significant change in the first resistance value at the first charging state value, similar to the third resistance value at the third charging state value or the second resistance value at the second charging state value. In this case, the third ratio has a value lower than a predetermined threshold, and the server (100) can diagnose that the dominant active region of the second component of the mixed cathode is the first charge state, the second charge state, and the third charge state.

[0076] FIG. 6 is a diagram for explaining a Nyquist plot analysis process in a method for diagnosing an active area of ​​a battery cell according to one embodiment.

[0077] Referring to FIG. 6, a server (100) according to an embodiment may obtain information on impedance change according to frequency by performing Nyquist plot analysis on impedance information as examined in FIGS. 2 and 4A. In this case, the plot analysis may be performed on at least one of a frequency section selected based on a user input or a frequency section arbitrarily selected by the server. For example, the server (100) may perform a frequency section (e.g., In Hz In the frequency range of Hz), impedance change information (620-1; 620-2; 620-3) can be obtained according to the battery charge status value. Based on the first frequency value (510-1) and the second frequency value (510-2) described in FIG. 5, the server (100) can diagnose that the battery charge status corresponds to a charge status corresponding to a predominantly active region of the first component when the difference between the resistance value when the frequency is the first frequency value (510-1) and the resistance value when the frequency is the second frequency value (510-2) changes rapidly in each of the change information.

[0078] For example, the 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) of the impedance change information (620-1) at the first charge state value. Furthermore, in the change information (620-2) in the second charge state value which is less than the first charge state value, the difference (650-2) between the resistance value (630-2) in the first frequency value (510-1) and the resistance value (640-2) in the second frequency value (510-2) can be obtained, and in the change information (620-3) in the third charge state value which is less than the second charge state value, the difference (650-3) between the resistance value (630-3) in the first frequency value (510-1) and the resistance value (640-3) in the second frequency value (510-2) can be obtained.

[0079] As can be seen in Fig. 6, when the difference (650-1) in the first state of charge value is determined to be greater than a threshold value compared to the difference (650-2) in the second state of charge value and the difference (650-3) in the third state of charge value as the state of charge value of the battery cell continuously decreases from the first state of charge value to the third state of charge value, the server (100) can diagnose that the first state of charge is a state of charge corresponding to a predominant active area of ​​the first component of the mixed negative electrode based on input regarding active area diagnosis received from a user terminal (not shown).

[0080] The description of the method for diagnosing an active area of ​​a battery cell according to the present disclosure in FIGS. 5 and 6 has been made based on a change in which the state of charge of the battery cell continuously decreases based on a first state of charge value, a second state of charge value that is less than the first state of charge value, and a third state of charge value that is less than the second state of charge value. However, it is obvious that one embodiment of the method for diagnosing an active area of ​​a battery cell according to the present disclosure also applies to a change in which the state of charge of the battery cell continuously increases.

[0081]

[0082] Figure 7 illustrates a block diagram of a server according to one embodiment.

[0083] According to one embodiment, the server (100) may include a memory (101) and a processor (102). The server (100) illustrated in FIG. 7 only illustrates components related to the present embodiment. Therefore, those skilled in the art will understand that, in addition to the components illustrated in FIG. 7, other general-purpose components may be included. In one embodiment, the processor (102) may be included in a controller.

[0084] The processor (102) can control the overall operation of the server (100) and process data and signals. The processor (102) can be composed of at least one hardware unit. In addition, the processor (102) can operate by one or more software modules generated by executing program codes stored in the memory (101). The processor (102) can include a memory, and the processor (102) can control the overall operation of the server (100) and process data and signals by executing the program codes stored in the memory.

[0085] The processor (102) may be configured to perform electrochemical impedance spectroscopy on a target battery cell to be diagnosed, thereby obtaining impedance information about the battery cell, obtaining impedance change information according to frequency based on the impedance information, and diagnosing an active area of ​​the target battery cell based on the impedance change information.

[0086] Depending on the embodiment, the server (100) may additionally include a transceiver for performing wired / wireless communication. The server (100) may 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. In addition, the communication technologies used by the transceiver may include GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), LTE (Long Term Evolution), 5G, WLAN (Wireless LAN), Wi-Fi (Wireless-Fidelity), Bluetooth (Bluetooth), RFID (Radio Frequency Identification), Infrared Data Association (IrDA), ZigBee, NFC (Near Field Communication), etc.

[0087] The server according to the above-described embodiments may include a processor, a memory for storing and executing program data, permanent storage such as a disk drive, a communication port for communicating with an external device, and a user interface device such as a touch panel, a key, a button, etc. Methods implemented as software modules or algorithms may be stored on a computer-readable recording medium as computer-readable codes or program instructions executable on the processor. Here, the computer-readable recording medium includes a magnetic storage medium (e.g., read-only memory (ROM), random-access memory (RAM), floppy disk, hard disk, etc.) and an optical reading medium (e.g., CD-ROM, DVD (Digital Versatile Disc)). The computer-readable recording medium may be distributed to computer systems connected to a network, so that the computer-readable code may be stored and executed in a distributed manner. The medium may be readable by a computer, stored in a memory, and executed by a processor.

[0088]

[0089] The present embodiment may be represented by functional block configurations and various processing steps. These functional blocks may be implemented by various hardware and / or software configurations that perform specific functions. For example, the embodiment may employ direct circuit configurations such as memory, processing, logic, look-up tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. Similarly, the present embodiment may be implemented in a programming or scripting language such as C, C++, Java, assembler, etc., including various algorithms implemented as a combination of data structures, processes, routines, or other programming configurations. Functional aspects may be implemented as algorithms that execute on one or more processors. Furthermore, the present embodiment may employ conventional techniques for electronic configuration, signal processing, and / or data processing. Terms such as "mechanism," "element," "means," and "composition" can be used broadly and are not limited to mechanical or physical structures. These terms can also encompass a series of software routines, such as those associated with a processor.

[0090] The above-described embodiments are merely examples, and other embodiments may be implemented within the scope of the claims set forth below.

Claims

1. A method for diagnosing an active area of ​​a battery cell including a mixed cathode in which a first component and a second component are mixed and performed on a server, A step of obtaining impedance information about a battery cell by performing electrochemical impedance spectroscopy on the target battery cell to be diagnosed; A step of obtaining information on impedance change according to frequency based on the above impedance information; and A step of diagnosing an active area of ​​the target battery cell based on the impedance change information, How to diagnose the active area of ​​a battery cell.

2. In paragraph 1, The step of obtaining the above impedance change information is: It includes a step of generating a graph representing the size of the impedance according to the frequency by performing a Distribution of Relaxation Times (DRT) on the above impedance information, The above diagnostic steps are: Comprising a step of diagnosing the active area of ​​the mixed cathode based on the above graph, How to diagnose the active area of ​​a battery cell.

3. In paragraph 2, The steps for generating the above graph are: A step of generating graphs representing the size of the impedance according to the frequency according to the change in the state of charge value (SoC) of the target battery cell is included. The above diagnostic steps are: A step of diagnosing an active area of ​​the target battery cell based on a first resistance value of the impedance of the first graph at a first state of charge value; a second resistance value of the impedance of the second graph at a second state of charge value that is less than the first state of charge value; and a third resistance value of the impedance of the third graph at a third state of charge value that is less than the second state of charge value. How to diagnose the active area of ​​a battery cell.

4. In paragraph 3, The above diagnostic steps are: A step of calculating a first ratio of the first resistance value to the second resistance value; A step of calculating a second ratio of the second resistance value to the third resistance value; A step of calculating a third ratio, which is a ratio of the second ratio to the first ratio; and A step of diagnosing that the dominant active region of the first component of the mixed cathode is in the first charge state when the third ratio is greater than or equal to a predetermined threshold value, How to diagnose the active area of ​​a battery cell.

5. In paragraph 3, The above diagnostic steps are: A step of calculating a first ratio of the first resistance value to the second resistance value; A step of calculating a second ratio of the second resistance value to the third resistance value; A step of calculating a third ratio, which is a ratio of the second ratio to the first ratio; and A step of diagnosing that the dominant active region of the second component of the mixed cathode is a first charge state, a second charge state, and a third charge state when the third ratio is less than a predetermined threshold value, How to diagnose the active area of ​​a battery cell.

6. In paragraph 3, The first resistance value is obtained based on a value obtained by integrating the first graph according to the frequency, the second resistance value is obtained based on a value obtained by integrating the second graph according to the frequency, and the third resistance value is obtained based on a value obtained by integrating the third graph according to the frequency. How to diagnose the active area of ​​a battery cell.

7. In paragraph 1, The step of obtaining information on impedance change according to the above frequency is: A step of obtaining information on impedance change according to frequency by performing Nyquist plot analysis on the above impedance information is included. The above plot analysis is performed on at least one of a frequency interval selected based on user input or a randomly selected frequency interval. How to diagnose the active area of ​​a battery cell.

8. In paragraph 1, The above first component is a SiO component, The second component is a graphite component. How to diagnose the active area of ​​a battery cell.

9. In paragraph 1, The above obtaining steps are: A step of obtaining impedance information about the target battery cell by performing electrochemical impedance spectroscopy on the target battery cell above a predefined temperature, How to diagnose the active area of ​​a battery cell.

10. A non-transitory computer-readable storage medium having recorded thereon a program for executing the method of any one of clauses 1 to 9 on a server.

11. On the server, memory for storing instructions; and comprising a processor connected to said memory, The above processor, By performing electrochemical impedance spectroscopy on a target battery cell to be diagnosed, impedance information on the battery cell is obtained from a battery management device, Based on the above impedance information, information on impedance change according to frequency is obtained, and Set to diagnose the active area of ​​the target battery cell based on the above impedance change information. Server.

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