Battery diagnosis device and battery diagnosis method using same

Abstract

A battery diagnosis device according to an aspect of the present invention comprises: a diagnosis model construction unit configured to construct a first Nyquist plot, in which determination parameters constituting a form of a Nyquist plot are displayed by using first AC impedance data that is reference AC impedance data measured for a first battery, which is a normal battery at different frequencies, by means of electrochemical impedance spectroscopy (EIS), and derive measurement parameters matching the determination parameters from an equivalent circuit model that is constructed by using second AC impedance data measured for a second battery, which is a failure diagnosis target battery at different frequencies, by means of the electrochemical impedance spectroscopy; and a battery failure diagnosis unit configured to diagnose a failure of the second battery by comparing at least one of the determination parameters and at least one of the measurement parameters.

Description

Battery diagnostic device and battery diagnostic method using the same

[0001] The present invention relates to a battery diagnostic device and a battery diagnostic method using the same, and more particularly, to a battery diagnostic device capable of quickly measuring battery defects using electrochemical impedance spectroscopy (EIS) and a battery diagnostic method using the same.

[0002] Batteries, which are easy to apply to various product groups and have electrical characteristics such as high energy density, are also called accumulators or secondary batteries. In addition to their primary advantage of reducing the use of fossil fuels, they are attracting attention as a new energy source for environmental friendliness and energy efficiency enhancement because they do not generate any byproducts from energy use.

[0003] Therefore, batteries are widely used in portable devices, electric vehicles (EVs) driven by electrical power sources, and energy storage systems (ESSs), and research and development on battery management systems (BMSs), battery balancing circuits, and switching circuits are actively being conducted for more efficient battery management.

[0004] Meanwhile, the increased performance and capacity of these batteries can lead to system malfunctions, such as fires or explosions, which can lead to major accidents. Therefore, it is crucial to not only ensure safety and reliability during battery manufacturing, but also quickly and accurately diagnose defective batteries.

[0005] The purpose of the present invention is to provide a battery diagnostic device capable of quickly measuring a defect in a battery based on AC impedance data of the battery measured using electrochemical impedance spectroscopy, and a battery diagnostic method using the same.

[0006] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0007] According to one aspect of the present invention, a battery diagnosis device comprises: a diagnosis model construction unit configured to construct a first Nyquist plot in which judgment parameters constituting the form of a Nyquist plot are displayed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy (EIS); and a battery failure diagnosis unit configured to diagnose a failure of the second battery by comparing at least one of the judgment parameters with at least one of the measurement parameters.

[0008] Preferably, the diagnostic model configuration unit may include a normal battery impedance measurement unit that configures the first Nyquist plot and an equivalent circuit model formation unit that forms the equivalent circuit model and is configured to derive the measurement parameters.

[0009] Preferably, the diagnostic model configuration unit further includes a battery type determination unit configured to determine the type of the second battery, and the equivalent circuit model formation unit may be configured to derive measurement parameters that match the determination parameters of the first battery corresponding to the determined type of the second battery.

[0010] Preferably, the normal battery impedance measuring unit may be configured to display the judgment parameters on the first Nyquist plot as a starting point of a semicircle of the first Nyquist plot, an ending point of a semicircle of the first Nyquist plot, a point where the negative value of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a last measurement point of the first AC impedance data.

[0011] Preferably, the battery failure diagnosis unit further includes a partial impedance measurement unit that constitutes a second Nyquist plot in which the derived measurement parameters are displayed to match the display positions of the judgment parameters on the first Nyquist plot, and the partial impedance measurement unit can be configured to derive first comparison data by comparing at least one of the judgment parameters with at least one of the measurement parameters.

[0012] Preferably, the partial impedance measurement unit may be configured to display the measurement parameters on the second Nyquist plot as a first point matching a starting point of a semicircle of the first Nyquist plot, a second point matching a ending point of a semicircle of the first Nyquist plot, a third point matching a point where a negative value of an imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a fourth point matching a last measurement point of the first AC impedance data.

[0013] Preferably, the battery failure diagnosis unit further includes a total impedance estimation unit that connects the judgment parameters on the second Nyquist plot to form a third Nyquist plot corresponding to the graph trend of the first Nyquist plot and the overall shape of the first Nyquist plot, and the total impedance estimation unit may be configured to derive second comparison data that compares at least one of the similarity of the graph trends of the first Nyquist plot and the third Nyquist plot and the overall shapes of the first Nyquist plot and the third Nyquist plot.

[0014] Preferably, the battery failure diagnosis unit may further include a measurement parameter analysis unit configured to diagnose a failure of the second battery using the first comparison data and the second comparison data.

[0015] A battery diagnosis method according to one aspect of the present invention comprises the steps of: constructing a first Nyquist plot in which judgment parameters constituting the shape of a Nyquist plot are displayed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy; deriving measurement parameters matching the judgment parameters from an equivalent circuit model formed using second AC impedance data measured for a second battery, which is a battery to be diagnosed as defective, at different frequencies using the electrochemical impedance spectroscopy; and diagnosing a defect in the second battery by comparing at least one of the judgment parameters with at least one of the measurement parameters.

[0016] According to an embodiment of the present invention, standardized measurement parameters for diagnosing a defect in a battery to be diagnosed as defective can be derived based on judgment parameters on a first Nyquist plot derived using first AC impedance data measured for a normal battery, so there is an advantage in that the defect in the battery to be diagnosed as defective can be diagnosed more quickly while accurately diagnosing it.

[0017] In addition, various additional effects can be achieved through various embodiments of the present invention. These various effects of the present invention will be described in detail in each embodiment, or descriptions of effects easily understandable to those skilled in the art will be omitted.

[0018] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0019] FIG. 1 is a drawing showing a battery diagnostic device according to one embodiment of the present invention.

[0020] FIG. 2 is a diagram exemplarily showing a first Nyquist plot constructed by a normal battery impedance measurement unit of a diagnostic model configuration unit equipped in the battery diagnostic device of FIG. 1.

[0021] FIG. 3 is a drawing exemplarily showing an equivalent circuit model formed by an equivalent circuit model forming unit of a diagnostic model forming unit equipped in the battery diagnostic device of FIG. 1.

[0022] FIG. 4 is a diagram exemplarily showing a second Nyquist plot constructed by a partial impedance measurement unit of a battery failure diagnosis unit equipped in the battery diagnosis device of FIG. 1.

[0023] FIG. 5 is a diagram illustrating a third Nyquist plot constructed by the entire impedance measurement unit of the battery failure diagnosis unit equipped in the battery diagnosis device of FIG. 1.

[0024] FIG. 6 and FIG. 7 are drawings showing an example of a battery failure diagnosis process by a measurement parameter analysis unit of a battery failure diagnosis unit equipped in the battery diagnosis device of FIG. 1.

[0025] Figure 8 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0026] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the present invention, and the present invention is defined solely by the scope of the claims.

[0027] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0028] Throughout the specification, the same reference numerals refer to the same elements, and the term "and / or" includes each and every combination of the elements mentioned. Although terms such as "first," "second," etc. are used to describe various elements, these elements are not limited by these terms. These terms are used only to distinguish one element from another. Therefore, it should be understood that a first element mentioned below may also be a second element within the technical scope of the present invention.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0030] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0031] In describing the present invention, a "battery" may be a capacitor or secondary battery that stores power by charging. Furthermore, the battery may include at least one of a battery pack comprising a plurality of battery modules, at least one battery module within the battery pack, a battery module comprising a plurality of battery cells, at least one battery cell within the battery module, a representative module representing a plurality of battery modules, and a representative cell representing a plurality of battery cells.

[0032] FIG. 1 is a diagram showing a battery diagnosis device (10) according to one embodiment of the present invention, FIG. 2 is a diagram exemplarily showing a first Nyquist plot configured by a normal battery impedance measurement unit (110) of a diagnosis model configuration unit (100) equipped in the battery diagnosis device (10) of FIG. 1, and FIG. 3 is a diagram exemplarily showing an equivalent circuit model (ECM, equivalent circuit model) configured by an equivalent circuit model formation unit (130) of a diagnosis model configuration unit (100) equipped in the battery diagnosis device (10) of FIG. 1. At this time, in FIG. 2, the first Nyquist plot for the first battery, which is a pouch-type battery, and the first Nyquist plot for the first battery, which is a square battery, can be simultaneously shown.

[0033] Referring to FIGS. 1 to 3, a battery diagnostic device (10) according to one embodiment of the present invention may include a diagnostic model configuration unit (100) and a battery failure diagnostic unit (200).

[0034] The above diagnostic model configuration unit (100) can configure a first Nyquist plot in which judgment parameters forming the shape of a Nyquist plot are displayed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy (EIS). At this time, the Nyquist plot may include a portion of a semicircular shape.

[0035] As an example, the diagnostic model configuration unit (100) can apply an input signal while modulating the frequency to the first battery, measure the output signal, and calculate a reference AC impedance according to the frequency from the input signal and the output signal. For example, the frequency modulation range of the input signal can be 4000 Hz to 0.1 Hz.

[0036] In addition, the diagnostic model configuration unit (100) can separate the measured first AC impedance data by frequency. In addition, the diagnostic model configuration unit (100) can obtain the real component (Zre) and the imaginary component (Zimg) of the first AC impedance data and configure them into a first Nyquist plot. At this time, the real component of the first AC impedance data represents the resistance value of the first AC impedance data and can configure the horizontal axis of the first Nyquist plot. In addition, the imaginary component of the first AC impedance data represents at least one of the inductance value or the capacitance value of the first AC impedance data, and the negative value (-Zimg) of the imaginary component of the first AC impedance data can configure the vertical axis of the first Nyquist plot.

[0037] In addition, the above diagnostic model configuration unit (100) may be configured to derive measurement parameters matching the judgment parameters from an equivalent circuit model formed using second AC impedance data measured at different frequencies for the second battery, which is a target battery for defective diagnosis, using electrochemical impedance spectroscopy. As an example, the second battery, which is a target battery for defective diagnosis, may have the same specifications as the first battery, which is a normal battery.

[0038] As an example, the diagnostic model configuration unit (100) can apply an input signal while modulating the frequency to the second battery, measure the output signal, and calculate a second AC impedance according to the frequency from the input signal and the output signal. For example, the frequency modulation range of the input signal can be from 4000 Hz to 0.1 Hz.

[0039] And the diagnostic model component (100) can separate the measured second AC impedance data by frequency.

[0040] Specifically, the diagnostic model configuration unit (100) may include a normal battery impedance measurement unit (110), a battery type determination unit (120), an equivalent circuit model formation unit (130), and an OCV measurement unit (140).

[0041] The above normal battery impedance measurement unit (110) can configure the first Nyquist plot.

[0042] In one embodiment, the normal battery impedance measuring unit (110) may be configured to display the above judgment parameters on the first Nyquist plot as, for example, a starting point (ZO) of the semicircle of the first Nyquist plot, an ending point (Zmin) of the semicircle of the first Nyquist plot, a point (Zmax) where the negative value (-Zimg) of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a last measurement point (Zend) of the first AC impedance data, as shown in FIG. 2.

[0043] At this time, the starting point (ZO) of the semicircle of the first Nyquist plot can be set by deriving a point where the imaginary component (Zimg) of the first AC impedance data is 0 through interpolation based on the frequency at which the sign of the imaginary component (Zimg) of the first AC impedance data changes and the frequency immediately before the sign change of the imaginary component (Zimg) of the first AC impedance data.

[0044] In addition, the point (Zmax) at which the negative value (-Zimg) of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot can be set by deriving the point at which the imaginary component (Zimg) of the first AC impedance data starts to decrease and then increase in the frequency range after the starting point (ZO) of the semicircle of the first Nyquist plot.

[0045] In addition, the semicircle end point (Zmin) of the first Nyquist plot can be set by deriving a point where the imaginary component (Zimg) of the first AC impedance data begins to increase and then decrease in the frequency range after the point (Zmax) where the negative value (-Zimg) of the imaginary component of the first AC impedance data in the semicircle of the first Nyquist plot is maximum.

[0046] The purpose of constructing the first Nyquist plot by focusing on the judgment parameters that form the shape of the Nyquist plot is to quickly and precisely verify the defect of the battery by comparing it with the Nyquist plot (the second Nyquist plot and the third Nyquist plot described below) derived from the battery to be diagnosed as defective (the second battery) by focusing on the judgment parameters.

[0047] The battery type determination unit (120) may be configured to determine the type of the second battery. For example, the battery type determination unit (120) may be configured to determine whether the second battery is a square battery or a pouch-type battery.

[0048] The equivalent circuit model forming unit (130) may be configured to form the equivalent circuit model using the second AC impedance data measured for the second battery, and derive measurement parameters matching the judgment parameters from the equivalent circuit model. At this time, the measurement parameters derived from the equivalent circuit model may include electrolyte resistance (Rs), charge transfer resistance (Rct), electric double layer capacitance (Cdl), and Warburg impedance (Wo).

[0049] As an example, the equivalent circuit model forming unit (130) can construct an equivalent circuit model according to the CNLS (Complex Nonlinear Least Square) fitting method for the second AC impedance data and derive measurement parameters (Rs, Rct, Cdl, Wo) matching the judgment parameters.

[0050] Here, the equivalent circuit model forming unit (130) may be configured to derive measurement parameters that match the judgment parameters of the first battery corresponding to the type of the second battery determined by the battery type determining unit (120). As an example, if the type of the second battery determined by the battery type determining unit (120) is a pouch type (or square type), the equivalent circuit model forming unit (130) may derive measurement parameters that match the judgment parameters of the first battery that is a pouch type (or square type).

[0051] For example, the equivalent circuit model forming unit (130) can be configured to derive measurement parameters based on the frequency values ​​of the judgment parameters in the first Nyquist plot.

[0052] At this time, Rs may be a measurement parameter corresponding to the starting point of the semicircle (Z0) of the first Nyquist plot.

[0053] Additionally, Rct may be a measurement parameter corresponding to the semicircle end point (Zmin) of the first Nyquist plot.

[0054] Additionally, Cdl may be a measurement parameter corresponding to a point (Zmax) where the negative value (-Zimg) of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot.

[0055] Additionally, Wo may be a measurement parameter corresponding to the last measurement point (Zend) of the first AC impedance data.

[0056] The above OCV measurement unit (140) measures the EIS measurement voltage (i.e., OCV: Open Circuit Voltage) when the diagnostic model configuration unit (100) applies an input signal while modulating the frequency to the second battery, measures the output signal, and calculates the second AC impedance according to the frequency from the input signal and the output signal, and can set the OCV within a range of 1.2 V or more and 3.55 V or less, for example.

[0057] Additionally, the battery failure diagnosis unit (200) may be configured to diagnose a failure of the second battery by comparing at least one of the judgment parameters with at least one of the measurement parameters. This will be discussed in detail in the related description that follows.

[0058] According to this embodiment of the present invention, standardized measurement parameters for diagnosing a defect in a battery to be diagnosed as defective can be derived based on judgment parameters on a first Nyquist plot derived using first AC impedance data measured for a normal battery, so there is an advantage in that the defect in the battery to be diagnosed as defective can be diagnosed more quickly while accurately diagnosing it.

[0059] FIG. 4 is a drawing exemplarily showing a second Nyquist plot constructed by a partial impedance measurement unit (210) of a battery failure diagnosis unit (200) equipped in a battery diagnosis device (10) of FIG. 1.

[0060] Referring to FIGS. 1 and 4, the battery failure diagnosis unit (200) may include a partial impedance measurement unit (210).

[0061] The above partial impedance measurement unit (210) can configure a second Nyquist plot in which the derived measurement parameters are displayed so as to match the display positions of the judgment parameters on the first Nyquist plot.

[0062] Specifically, the partial impedance measurement unit (210) can obtain the real component (Zre) and the imaginary component (Zimg) of the measurement parameters and construct a second Nyquist plot using them. At this time, the real component of the measurement parameters represents the resistance value of the measurement parameters and can construct the horizontal axis of the second Nyquist plot. In addition, the imaginary component of the measurement parameters represents at least one of the inductance value or the capacitance value of the measurement parameters, and the negative value (-Zimg) of the imaginary component of the measurement parameters can construct the vertical axis of the second Nyquist plot.

[0063] For example, the partial impedance measurement unit (210) may be configured to display the measurement parameters on the second Nyquist plot as a first point matching a semicircle start point (Z0) of the first Nyquist plot, a second point matching a semicircle end point (Zmin) of the first Nyquist plot, a third point matching a point (Zmax) where the negative value (-Zimg) of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a fourth point matching a last measurement point (Zend) of the first AC impedance data.

[0064] At this time, the first point may correspond to 'Rs' among the aforementioned measurement parameters, the second point may correspond to 'Rct' among the aforementioned measurement parameters, the third point may correspond to 'Cdl' among the aforementioned measurement parameters, and the fourth point may correspond to 'Wo' among the aforementioned measurement parameters.

[0065] At this time, the partial impedance measurement unit (210) may be configured to derive first comparison data by comparing at least one of the judgment parameters with at least one of the measurement parameters.

[0066] These first comparison data can be the primary verification factor for the diagnosis of a defect in the second battery.

[0067] FIG. 5 is a drawing exemplarily showing a third Nyquist plot constructed by the entire impedance measurement unit (220) of the battery failure diagnosis unit (200) equipped in the battery diagnosis device (10) of FIG. 1.

[0068] Referring to FIGS. 1 and 5, the battery failure diagnosis unit (200) may further include an overall impedance estimation unit (220).

[0069] The above overall impedance estimation unit (220) can connect the judgment parameters on the second Nyquist plot to form a third Nyquist plot corresponding to the graph trend of the first Nyquist plot and the overall shape of the first Nyquist plot.

[0070] Specifically, in the third Nyquist plot, the real component of the measurement parameters represents the resistance value of the measurement parameters and may constitute the horizontal axis of the third Nyquist plot. In addition, the imaginary component of the measurement parameters in the third Nyquist plot represents at least one of the inductance value or the capacitance value of the measurement parameters, and the negative value (-Zimg) of the imaginary component of the measurement parameters may constitute the vertical axis of the third Nyquist plot.

[0071] And, the overall impedance estimation unit (220) can connect the first point (Rs), the second point (Rct), the third point (Cdl), and the fourth point (Wo) described above on the second Nyquist plot to form a third Nyquist plot.

[0072] At this time, the overall impedance estimation unit (220) may be configured to derive second comparison data comparing at least one of the similarity of the graph trends of the first Nyquist plot and the third Nyquist plot and the overall shapes of the first Nyquist plot and the third Nyquist plot.

[0073] That is, the overall impedance estimation unit (220) can determine whether the increase / decrease trends of the graphs of the first Nyquist plot and the third Nyquist plot are similar, and whether the overall shapes of the first Nyquist plot and the third Nyquist plot are similar.

[0074] This second comparison data may be a secondary verification element for the diagnosis of a defect in the second battery.

[0075] Figures 6 and 7 are diagrams exemplarily showing a battery failure diagnosis process by a measurement parameter analysis unit (230) of a battery failure diagnosis unit (200) equipped in the battery diagnosis device (10) of Figure 1. At this time, Figure 6 is a diagram exemplarily showing a failure diagnosis process of a second battery, which is a pouch-type battery, and Figure 7 is a diagram exemplarily showing a failure diagnosis process of a second battery, which is a square battery.

[0076] Referring to FIG. 1, FIG. 6 and FIG. 7, the battery failure diagnosis unit (200) may further include a measurement parameter analysis unit (230).

[0077] The above measurement parameter analysis unit (230) may be configured to diagnose a defect in the second battery using the first comparison data and the second comparison data.

[0078] That is, the measurement parameter analysis unit (230) can diagnose a defect in the second battery by using first comparison data derived by comparing at least one of the judgment parameters with at least one of the measurement parameters by the partial impedance measurement unit (210) as in FIGS. 6 and 7, and second comparison data derived by comparing at least one of the similarity of the graph trends of the first Nyquist plot and the third Nyquist plot and the overall shapes of the first Nyquist plot and the third Nyquist plot by the overall impedance estimation unit (220).

[0079] According to this implementation configuration, the battery defect can be diagnosed using the standardized minimum measurement parameters for diagnosing the defect of the target battery, so there is an advantage in that a faster battery defect diagnosis is possible.

[0080] Figure 8 is a flowchart illustrating a battery diagnosis method according to one embodiment of the present invention.

[0081] Referring to FIG. 8, a battery diagnosis method according to one embodiment of the present invention includes the following steps S1 and S2.

[0082] In the above step S1, a first Nyquist plot is constructed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy, and judgment parameters that constitute the shape of the Nyquist plot are displayed, and measurement parameters that match the judgment parameters are derived from an equivalent circuit model formed using second AC impedance data measured for a second battery, which is a target battery for defective diagnosis, at different frequencies using electrochemical impedance spectroscopy. At this time, the above step S1 may be performed by the above-described diagnosis model construction unit (100).

[0083] In the above step S2, at least one of the judgment parameters is compared with at least one of the measurement parameters to diagnose a defect in the second battery. At this time, the step S2 may be performed by the battery defect diagnosis unit (200) described above.

[0084] As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited thereto, and various modifications and variations are possible by a person having ordinary skill in the art to which the present invention pertains within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below.

[0085] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back are used in the present invention, it is obvious to those skilled in the art that these terms are only for the convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0086] [Explanation of symbols]

[0087] 10: Battery diagnostic device

[0088] 100: Diagnostic model component

[0089] 110: Normal battery impedance measurement unit

[0090] 120: Battery type determination unit

[0091] 130: Equivalent circuit model formation section

[0092] 140: OCV measurement section

[0093] 200: Battery failure diagnosis section

[0094] 210: Partial impedance measurement unit

[0095] 220: Total impedance measurement unit

[0096] 230: Measurement parameter analysis section

Claims

1. A diagnostic model configuration unit configured to construct a first Nyquist plot in which judgment parameters forming a shape of a Nyquist plot are displayed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy (EIS), and to derive measurement parameters matching the judgment parameters from an equivalent circuit model formed using second AC impedance data measured for a second battery, which is a target battery for fault diagnosis, at different frequencies using the electrochemical impedance spectroscopy; and A battery diagnosis device characterized by including a battery failure diagnosis unit configured to diagnose a failure of the second battery by comparing at least one of the judgment parameters with at least one of the measurement parameters.

2. In paragraph 1, The above diagnostic model component is: A normal battery impedance measuring unit constituting the first Nyquist plot; and A battery diagnostic device characterized by including an equivalent circuit model forming unit configured to form the equivalent circuit model and derive the measurement parameters.

3. In paragraph 2, The above diagnostic model component is: Further comprising a battery type determination unit configured to determine the type of the second battery, The above equivalent circuit model forming part is, A battery diagnostic device characterized in that it is configured to derive measurement parameters that match the judgment parameters of the first battery corresponding to the type of the second battery determined above.

4. In paragraph 2, The above normal battery impedance measurement unit is, The above judgment parameters on the first Nyquist plot, A battery diagnostic device characterized in that it is configured to display a starting point of the semicircle of the first Nyquist plot, an ending point of the semicircle of the first Nyquist plot, a point where the negative value of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a last measurement point of the first AC impedance data.

5. In paragraph 2, The above battery failure diagnosis unit, The above-described derived measurement parameters further include a partial impedance measurement unit that constitutes a second Nyquist plot in which the derived measurement parameters are displayed to match the display positions of the judgment parameters on the first Nyquist plot, The above partial impedance measurement section is, A battery diagnostic device characterized in that it is configured to derive first comparison data by comparing at least one of the judgment parameters with at least one of the measurement parameters.

6. In paragraph 5, The above partial impedance measurement section is, The above measurement parameters on the second Nyquist plot, A battery diagnostic device characterized in that it is configured to display a first point matching a starting point of a semicircle of the first Nyquist plot, a second point matching a ending point of a semicircle of the first Nyquist plot, a third point matching a point where the negative value of the imaginary component of the first AC impedance data is maximum in the semicircle of the first Nyquist plot, and a fourth point matching a last measurement point of the first AC impedance data.

7. In paragraph 5, The above battery failure diagnosis unit, Further comprising a full impedance estimation unit that connects the judgment parameters on the second Nyquist plot to form a third Nyquist plot corresponding to the graph trend of the first Nyquist plot and the overall shape of the first Nyquist plot, The above overall impedance estimation unit is, A battery diagnostic device characterized in that it is configured to derive second comparison data comparing at least one of the similarity of the graph trends of the first Nyquist plot and the third Nyquist plot and the overall shapes of the first Nyquist plot and the third Nyquist plot.

8. In paragraph 7, The above battery failure diagnosis unit, A battery diagnosis device further comprising a measurement parameter analysis unit configured to diagnose a defect in the second battery using the first comparison data and the second comparison data.

9. In a battery diagnosis method performed by a battery diagnosis device, A step of constructing a first Nyquist plot in which judgment parameters forming the shape of a Nyquist plot are displayed using first AC impedance data, which is reference AC impedance data measured for a first battery, which is a normal battery, at different frequencies using electrochemical impedance spectroscopy, and deriving measurement parameters matching the judgment parameters from an equivalent circuit model formed using second AC impedance data measured for a second battery, which is a battery to be diagnosed as defective, at different frequencies using the electrochemical impedance spectroscopy; and A battery diagnosis method, characterized in that it comprises a step of diagnosing a defect in the second battery by comparing at least one of the judgment parameters with at least one of the measurement parameters.

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