Battery diagnostic device and its operating method

Abstract

A battery diagnostic device according to one embodiment of this document may include an interface for acquiring impedance based on the frequency of the voltage applied between each of a plurality of measurement points on the first electrode lead of a battery cell under inspection and the second electrode lead of the battery cell, and one or more processors for diagnosing the state of the battery cell based on a first impedance, which is the impedance between a first of the plurality of measurement points and the second electrode lead, a second impedance, which is the impedance between a second of the plurality of measurement points and the second electrode lead, and a first impedance change amount, which is the difference between the first impedance and the second impedance.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0045021 filed on April 5, 2023 and Korean Patent Application No. 10-2024-0046226 filed on April 4, 2024, and all the contents disclosed in the documents of the patent applications are incorporated herein by reference. The embodiments disclosed in this document relate to a battery diagnostic device and an operation method thereof.

Background Art

[0002] In recent years, research and development on secondary batteries have been actively conducted. Here, a secondary battery is a battery that can be charged and discharged, and can be interpreted to include all conventional Ni / Cd batteries, Ni / MH batteries, etc., and recent lithium-ion batteries. In recent years, its scope of use has been extended to the power source of electric vehicles and has attracted attention as a next-generation energy storage medium.

[0003] An electric vehicle receives electric power from the outside to charge a battery cell / module, and then discharges the battery cell / module to drive a motor to obtain power. Battery cells / modules are subject to internal deformation and denaturation due to various charge and discharges during production and use, and their physicochemical properties change. There is a need for a technology to diagnose and manage the state of battery cells / modules due to such battery deterioration and aging.

[0004] Tests on batteries can be performed for various purposes, such as diagnosing and analyzing the state of battery cells. For example, when using EIS (electrochemical impedance spectroscopy), abnormal battery cells can be detected based on the impedance of the battery cell to be inspected measured in a specific frequency range (e.g., the resonance frequency range). However, such a method has a problem of low diagnostic accuracy. Therefore, there is a need for a technology that can more accurately diagnose the state of battery cells.

Summary of the Invention

[0005] One objective of the embodiments disclosed in this document is to provide a battery diagnostic device and a method for operating the same that can manage abnormal battery cells based on impedance data measured at multiple measurement points on the electrode leads of a battery cell.

[0006] One objective of the embodiments disclosed herein is to provide a battery diagnostic device and a method of operating the same that can diagnose the location and extent of electrode defects based on impedance data measured at multiple measurement points on the electrode leads of a battery cell.

[0007] The technical problems of the embodiments disclosed in this document are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A battery diagnostic device according to one embodiment of this document may include an interface for acquiring impedance based on the frequency of the voltage applied between each of a plurality of measurement points on the first electrode lead of a battery cell under inspection and the second electrode lead of the battery cell, and one or more processors for diagnosing the state of the battery cell based on a first impedance, which is the impedance between a first of the plurality of measurement points and the second electrode lead, a second impedance, which is the impedance between a second of the plurality of measurement points and the second electrode lead, and a first impedance change amount, which is the difference between the first impedance and the second impedance.

[0009] According to the embodiment, the first point and the second point can be positioned apart in a second direction which intersects with the first direction which is the direction in which the first electrode lead protrudes from the battery cell. According to the embodiment, the first point and the second point can be located along a straight line in the second direction.

[0010] According to the embodiment, one or more processors compare the first impedance, the second impedance, and the first impedance change amount with predetermined thresholds, and if at least one of the first impedance, the second impedance, and the first impedance change amount is greater than the predetermined threshold, the battery cell can be diagnosed as being in an abnormal state.

[0011] According to the embodiment, one or more processors can determine the predetermined threshold based on the impedance at the frequency measured at the first point of a normal battery cell corresponding to the first point and the second point of a normal battery cell corresponding to the second point.

[0012] According to the embodiment, one or more processors can diagnose the state of the battery cell based on a third impedance, which is the impedance between a third point among the plurality of measurement points and the second electrode lead; a second impedance change, which is the difference between the second impedance and the third impedance; and a third impedance change, which is the difference between the first impedance and the third impedance.

[0013] According to the embodiment, the first point is located at a distance of a first interval from the second point in a second direction which intersects with the first direction in which the first electrode lead protrudes from the battery cell, and the third point can be located at a distance of a first interval from the second point in the direction opposite to the second direction.

[0014] According to the embodiment, one or more processors can diagnose the location where a defect has occurred in the battery cell under inspection based on the sign of the first impedance change.

[0015] According to the embodiment, one or more processors can diagnose that a defect has occurred at the first point of the battery cell under inspection if the first impedance change is a positive number, and diagnose that a defect has occurred at the second point of the battery cell under inspection if the first impedance change is a negative number.

[0016] According to the embodiment, the more one or more processors can diagnose that the degree of defect in the battery cell under inspection is greater the greater the magnitude of the first impedance, the magnitude of the second impedance, and the magnitude of the first impedance change is greater than the predetermined threshold.

[0017] An operating method for a battery diagnostic device according to one embodiment of this document may include the steps of: acquiring the impedance based on the frequency of the voltage applied between each of a plurality of measurement points on the first electrode lead of the battery cell to be inspected and the second electrode lead of the battery cell; and diagnosing the state of the battery cell based on a first impedance, which is the impedance between a first of the plurality of measurement points and the second electrode lead; a second impedance, which is the impedance between a second of the plurality of measurement points and the second electrode lead; and a first impedance change amount, which is the difference between the first impedance and the second impedance.

[0018] According to the embodiment, the first point and the second point can be positioned apart in a second direction which intersects with the first direction which is the direction in which the first electrode lead protrudes from the battery cell. According to the embodiment, the first point and the second point can be located along a straight line in the second direction.

[0019] According to the embodiment, the diagnostic step may include comparing the first impedance, the second impedance, and the first impedance change amount with a predetermined threshold, and diagnosing the battery cell as being in an abnormal state if at least one of the first impedance, the second impedance, and the first impedance change amount is greater than the predetermined threshold.

[0020] According to one embodiment, the diagnostic step may include determining the predetermined threshold based on the impedance at the frequency measured at the first normal battery cell corresponding to the first location and the second normal battery cell corresponding to the second location.

[0021] According to the embodiment, the diagnostic step can diagnose the state of the battery cell based on a third impedance, which is the impedance between the third point among the plurality of measurement points and the second electrode lead; a second impedance change, which is the difference between the second impedance and the third impedance; and a third impedance change, which is the difference between the first impedance and the third impedance.

[0022] According to the embodiment, the first point is located at a distance of a first interval from the second point in a second direction which intersects with the first direction in which the first electrode lead protrudes from the battery cell, and the third point can be located at a distance of a first interval from the second point in the direction opposite to the second direction.

[0023] According to one embodiment, the diagnostic step may include a step of diagnosing the location where a defect has occurred in the battery cell under test, based on the sign of the first impedance change.

[0024] According to the embodiment, in the step of diagnosing the position where the defect has occurred, when the first impedance change amount is a positive number, it is diagnosed that a defect has occurred at the first point of the battery cell to be inspected, and when the first impedance change amount is a negative number, it can be diagnosed that a defect has occurred at the second point of the battery cell to be inspected.

[0025] According to the embodiment, in the diagnosing step, the greater any one of the magnitude of the first impedance, the magnitude of the second impedance, and the magnitude of the first impedance change amount is than the predetermined threshold value, the greater the degree of the defect occurring in the battery cell to be inspected can be diagnosed.

Advantages of the Invention

[0026] The battery diagnosis device and its operation method disclosed in this document can manage abnormal battery cells based on impedance data measured at a plurality of measurement points of the electrode leads of the battery cell.

[0027] The battery diagnosis device and its operation method disclosed in this document can diagnose the position and degree of defects in the electrode based on impedance data measured at a plurality of measurement points of the electrode leads of the battery cell. In addition to this, various effects that can be directly or indirectly grasped can be provided by this document.

Brief Description of the Drawings

[0028] [Figure 1] It is a block diagram showing a battery pack according to an embodiment disclosed in this document. [Figure 2] It is a block diagram showing a battery diagnosis device according to an embodiment disclosed in this document. [Figure 3] It is a diagram showing the inside of a battery cell according to an embodiment disclosed in this document. [Figure 4] It is a diagram showing a method for measuring the impedance of the electrode lead of a battery cell according to an embodiment disclosed in this document. [Figure 5] This figure shows a method for diagnosing abnormal battery cells based on reactance using a battery diagnostic device according to one embodiment disclosed in this document. [Figure 6] This is a flowchart showing the operation of a battery diagnostic device according to one embodiment disclosed in this document. [Figure 7] This is a block diagram showing the hardware configuration of a computing system for performing the operation method of a battery diagnostic device according to one embodiment disclosed in this document. [Modes for carrying out the invention]

[0029] Various embodiments of the present invention are described below with reference to the accompanying drawings. However, this should be understood not as limiting the present invention to any particular embodiment, but rather as including various modifications, equivalents, and / or alternatives to the embodiments of the present invention.

[0030] The various embodiments and terminology used herein are not intended to limit the technical features described herein to any particular embodiment, but should be understood to include various modifications, equivalents, or substitutes of such embodiments. Figure 1 is a block diagram showing a battery pack according to one embodiment disclosed herein.

[0031] Figure 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document. Figure 3 shows the inside of a battery cell according to one embodiment disclosed in this document.

[0032] Figure 4 shows a method for measuring the impedance of electrode leads of a battery cell according to one embodiment disclosed in this document. Figure 5 shows a method by which a battery diagnostic device according to one embodiment disclosed in this document diagnoses abnormal battery cells based on reactance. Figure 6 is a flowchart showing the operation of a battery diagnostic device according to one embodiment disclosed in this document.

[0033] Figure 7 is a block diagram showing the hardware configuration of a computing system for performing the operation method of a battery diagnostic device according to one embodiment disclosed herein. In relation to the description, similar or related components may be referred to by similar reference numerals. The singular form of a noun corresponding to an item may include one or more of the item unless the context of the item clearly indicates otherwise.

[0034] In this document, each phrase such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C” may include any one of the items listed together with the applicable phrase, or any possible combination thereof. Terms such as “first,” “second,” “first,” “second,” “A,” “B,” “(a),” or “(b)” may be used merely to distinguish one component from other components and, unless otherwise stated, do not limit the component in any other respect (e.g., importance or order).

[0035] Wherever a component (e.g., the first) is referred to as being "coupled," "joined," or "connected" to another component (e.g., the second) with or without such terms, it means that the first component may be connected to the other component directly (e.g., by wire), wirelessly, or via the third component.

[0036] According to one embodiment, the methods according to the various embodiments disclosed herein may be provided in a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of an instrument-readable storage medium (e.g., compact disc read-only memory (CD-ROM)) or online (e.g., download or upload) via an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be at least temporarily stored or temporarily generated in an instrument-readable storage medium such as the memory of a manufacturer's server, an application store server, or an intermediary server.

[0037] According to various embodiments, each of the aforementioned components (e.g., a module or a program) may include one or more individuals, and some of the individuals may be separated and arranged in other components. According to various embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Alternatively or additionally, multiple components (e.g., a module or a program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the components of the multiple components before the integration. According to various embodiments, operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0038] Figure 1 is a block diagram showing a battery pack according to one embodiment disclosed in this document. Referring to Figure 1, the battery pack 1 may include a battery unit 12, a sensor unit 14, a switching unit 16, and a battery management system (BMS) 20. In this case, the battery pack 1 may be equipped with multiple battery units 12, sensor units 14, switching units 16, and battery management systems 20.

[0039] According to the embodiment, the battery unit 12 can supply power to a target device (not shown). For this purpose, the battery unit 12 can be electrically connected to the target device. Here, the target device may include electrical, electronic, or mechanical devices that operate on power supplied from the battery pack 1. For example, the target device may be, but is not limited to, an electric vehicle (EV) or an energy storage system (ESS).

[0040] According to one embodiment, the battery unit 12 may include at least one rechargeable battery cell 10. Here, the battery cell 10 may be the basic unit of a battery cell that can be used by charging and discharging electrical energy. For example, the battery cell 10 may be, but is not limited to, a lithium-ion (Li-ion) battery, a lithium-ion polymer (Li-ion polymer) battery, a nickel-cadmium (Ni-Cd) battery, a nickel-metal hydride (Ni-MH) battery, and the like. A detailed structure of the battery cell 10 will be described with reference to Figure 3.

[0041] According to the embodiment, multiple battery units 12 can be connected in series or in parallel. For example, a battery unit 12 may be a battery module, a battery bank, or a collection of battery cells (cell-to-pack structure).

[0042] According to one embodiment, the sensor unit 14 can acquire information about the battery unit 12. According to one embodiment, the sensor unit 14 can acquire values ​​(or information) regarding the state of each of the battery units 12. In one embodiment, the values ​​regarding the state may include one or more values ​​regarding the voltage, current, resistance, SOC (state of charge), SOH (state of health), temperature, or a combination thereof of the battery cells. According to this embodiment, the sensor unit 14 can provide information from each of the multiple battery units 12 to the battery management system 20.

[0043] According to one embodiment, the switching unit 16 may include elements for controlling the flow of current for charging or discharging the battery unit 12. For example, the switching unit 16 may include at least one relay and / or electromagnetic contactor, depending on the specifications of the battery pack 1.

[0044] According to the embodiment, the Battery Management System (BMS) 20 can monitor the voltage, current, temperature, etc., of the battery pack 1 and control or manage the battery pack 1 to prevent overcharging and over-discharging. For example, the Battery Management System 20 is an interface that receives input values ​​of the various parameters mentioned above, and may include a plurality of terminals and circuits connected to these terminals that process the input values. The Battery Management System 20 can also control the sensor unit 14 and / or the switching unit 16. For example, the Battery Management System 20 can be connected to a plurality of battery units 12, monitor the state of each of the plurality of battery units 12, and control the ON / OFF state of relays or contactors.

[0045] According to the embodiment, the operation of the battery management system 20 may be performed by a BMS (Battery Management System) in the vehicle, or it may be performed by various devices such as a server, cloud, charger, or charger / discharger.

[0046] The higher-level controller 2 can transmit control signals to the battery management system 20 for multiple battery units 12. This allows the battery management system 20 to be controlled based on the signals applied from the higher-level controller 2.

[0047] According to one embodiment, the battery management system 20 may include the battery diagnostic device 100 shown in Figure 2. According to another embodiment, the battery management system 20 may be a different system from the battery diagnostic device 100 shown in Figure 2. That is, the battery diagnostic device 100 shown in Figure 2 may be included in the battery pack 1, or it may be configured as another device outside the battery pack 1. For the sake of explanation, the following description will assume that the battery diagnostic device 100 is configured as another device outside the battery pack 1. Furthermore, the operation of the battery diagnostic device 100 described below may be performed by a BMS (Battery management system) in the vehicle, as well as by various devices such as a server, cloud, charger, or charger / discharger.

[0048] Figure 2 is a block diagram showing a battery diagnostic device according to one embodiment disclosed in this document. Figure 3 is a diagram showing the inside of a battery cell according to one embodiment disclosed in this document. Figure 4 is a diagram showing a method for measuring the impedance of the electrode leads of a battery cell according to one embodiment disclosed in this document. Figure 5 is a diagram showing how a battery diagnostic device according to one embodiment disclosed in this document diagnoses an abnormal battery cell based on its reactance. The operation of the battery diagnostic device 100 shown in Figure 2 will be described in detail below with reference to Figures 3 to 5.

[0049] First, referring to Figure 2, a battery diagnostic device 100 according to one embodiment disclosed in this document can diagnose the condition of a battery cell 10 (see Figure 1). For example, defects can occur in the battery cell 10 due to various causes such as defects during the production stage, internal deformation and modification due to multiple charge and discharge cycles, or external impact. Here, defects may include tab breakage inside the battery cell 10, electrode defects, or lithium deposition. The battery diagnostic device 100 according to the embodiment can diagnose abnormalities inside the battery cell 10 based on the impedance measured in the battery cell 10.

[0050] Referring to Figure 3, an electrode assembly 32 can be housed within the battery case 31 of the battery cell 10. Here, the electrode assembly 32 extends in the X-axis direction, which is the length direction of the battery cell 10, and may be stacked in the Y-axis direction, which is the height direction of the battery cell 10. In addition, electrode tabs 33 protrude from the electrode assembly 32 in the X-axis direction, and multiple electrode tabs 33 can be connected to electrode leads 34.

[0051] According to various embodiments, the weld between the electrode assembly 32 and the electrode tab 33, the weld between the electrode tab 33 and the electrode lead 34, the electrode tab 33, or the electrode lead 34 may be deformed and defective due to various physical and chemical external forces applied during the manufacturing and use of the battery cell 10. Here, a defect may mean a defect in the electrode assembly 32 (e.g., lithium deposition), a break in the electrode tab 33 35, or a faulty electrode lead 34 36. Such defects in the battery cell 10 can cause abnormalities such as low voltage, reduced charge / discharge performance, and ignition. Therefore, if a defect such as lithium deposition, a break in the tab 35, or a faulty electrode 36 occurs in the battery cell 10, the abnormal battery cell may exhibit different resistance characteristics compared to a normal battery cell.

[0052] According to various embodiments, the battery diagnostic device 100 can detect abnormalities in the battery cell 10 based on the amount of impedance change measured when a voltage is applied to the battery cell 10. Here, the amount of impedance change of the battery cell may mean the amount of impedance change of the battery cell due to frequency. However, conventional diagnostic techniques have the problem of a low detection rate of abnormal battery cells because they diagnose abnormal battery cells based only on the impedance measured at one position of the electrode lead 34.

[0053] In contrast, the battery diagnostic device 100 according to the embodiment can detect abnormalities in the battery cell 10 based on impedances measured at multiple measurement points on the electrode leads 34 of the battery cell 10. Here, multiple measurement points may mean that there are two or more measurement points on at least one of the first electrode (e.g., positive electrode) and second electrode (e.g., negative electrode) of the electrode lead 34. As a result, the battery diagnostic device 100 can detect abnormal behavior of impedance change amounts based on impedances measured at multiple measurement points and diagnose abnormal battery cells.

[0054] Referring again to Figure 2, the battery diagnostic device 100 may include an interface 110 and one or more processors 120. However, it is not limited to this, and other components may be further included in the battery diagnostic device 100, and two or more components may be integrated into one, or one component may be divided into two or more components.

[0055] According to one embodiment, the interface 110 can acquire impedance data measured from the electrode leads 34 of the battery cell under test. Here, the interface 110 may mean a configuration that can communicate with an external device via wired and / or wireless means. According to one embodiment, the interface 110 can acquire impedance data by communicating with an impedance measuring device (e.g., an EIS (electrochemical impedance spectroscopy) measuring device). Alternatively, the interface 110 can acquire impedance data by communicating with a BMS 20 (see Figure 1) or other infrastructure such as a server and the cloud.

[0056] According to the embodiment, the battery cell under inspection may refer to the pouch-type battery cell 10 shown in Figures 1 and 3, which is a bidirectional battery cell in which electrode leads 34 of different polarities are led out from both ends of the battery cell 10 in the longitudinal direction. However, it is not limited to this, and the battery cell under inspection may also refer to a unidirectional battery cell in which electrode leads 34 of different polarities are led out from the same end of the battery cell.

[0057] Referring to Figure 4, the impedance measuring device 150 is connected to the electrode leads 34 of the battery cell 10 under test and can measure the impedance of the battery cell 10 under test. The impedance measuring device 150 can be connected to the electrode leads 34 of the battery cell 10 by a predetermined connecting cable and connection terminals. For example, the impedance measuring device 150 can be connected to the first electrode lead 34a and the second electrode lead 34b via a pair of probes T.

[0058] According to the embodiment, the impedance measuring device 150 can measure the impedance of the battery cell 10 according to the frequency. For example, the impedance measuring device 150 may mean an EIS (Electrochemical Impedance Spectroscopy) measuring device. Here, the impedance measuring device 150 can apply a small AC current signal and / or AC voltage signal to the battery cell 10 under test while changing the frequency, measure the current and / or voltage signal output from the battery cell 10 under test in response to the applied signal, and obtain the impedance according to the frequency. According to the embodiment, in addition to impedance, the impedance measuring device 150 can determine various impedance-related parameters such as the phase angle of the impedance, resistance, and reactance according to the frequency.

[0059] According to the embodiment, the electrode leads (34a and 34b) of the battery cell 10 under test can include multiple measurement points (P1 to P6 and Q1 to Q6). For example, the first electrode lead 34a can include multiple measurement points (P1 to P6), and the second electrode lead 34b can include multiple measurement points (Q1 to Q6). In Figure 4, each electrode lead (34a and 34b) includes six measurement points, but is not limited to this; each electrode lead (34a and 34b) can include n measurement points (n is a natural number of 1 or more) corresponding to any position on the electrode lead.

[0060] According to the embodiment, the impedance measuring device 150 can measure the impedance between one of several measurement points (P1 to P6) on the first electrode lead 34a and one of several measurement points (Q1 to Q6) on the second electrode lead 34b. For example, as shown in Figure 4, if each electrode lead (34a and 34b) includes six measurement points, the impedance measuring device 150 can measure 36 different impedances.

[0061] According to the embodiment, if a portion (or one) of the multiple electrode tabs 33 (see Figure 3) is disconnected, the closer the measurement point of the electrode lead (34a and 34b) is to the portion of the electrode tab 33 that is disconnected, the higher the measured impedance. Here, the electrode leads (34a and 34b) are connected to the multiple electrode tabs 33. Therefore, if a disconnection occurs in a particular electrode tab, the impedance measured at a measurement point close to the disconnected electrode tab will be higher than the impedance measured at a measurement point close to a normal electrode tab. For example, if the electrode tab 33 closest to a first point P1 is disconnected, the impedance between the first point P1 of the first electrode lead 34a and the first point Q1 of the second electrode lead 34b will be higher than the impedance between other points on the first electrode lead 34a (e.g., P2 or P3) and other points on the second electrode lead 34b (Q2 or Q3).

[0062] Therefore, if the battery diagnostic device 100 were to diagnose an abnormality in the battery cell 10 using the impedance measured at one measurement point on the electrode leads (34a and 34b), there would be a problem of misdiagnosis of an abnormal battery cell as a normal battery cell, resulting in low accuracy. In contrast, the battery diagnostic device 100 according to this embodiment can acquire impedances measured at multiple measurement points and accurately diagnose the state of the battery cell 10 based on the acquired impedances. In other respects, the battery diagnostic device 100 can diagnose the state of the battery cell 10 based on multiple impedances, thereby improving the accuracy of the diagnosis.

[0063] According to one embodiment, the interface 110 can acquire the frequency impedance between each of several measurement points (e.g., P1 and P2) on the first electrode lead 34a of the battery cell 10 under test and a single measurement point (e.g., Q2) on the second electrode lead 34b. In another aspect, the interface 110 can acquire a first impedance Z1, which is the frequency impedance of the AC voltage applied between the first point P1 on the first electrode lead 34a and the measurement point Q2 on the second electrode lead 34b. The interface 110 can also acquire a second impedance Z2, which is the frequency impedance of the AC voltage applied between the second point P2 on the first electrode lead 34a and the measurement point Q2 on the second electrode lead 34b.

[0064] According to the embodiment, with respect to one measurement point (e.g., Q2) on the second electrode lead 34b, the Y-axis positions of multiple measurement points (e.g., P1, P3, and P5) on the first electrode lead 34a may differ from each other. Here, the Y-axis direction may mean a second direction that intersects a first direction, which is the direction in which the first electrode lead 34a protrudes from the battery cell 10. Therefore, the first point P1 and the second point P2 on the first electrode lead 34a can be located apart in the second direction (Y-axis direction). On the other hand, if the measurement point (e.g., Q2) on the second electrode lead 34b is fixed to one, the multiple measurement points (e.g., P1, P3, and P5) on the first electrode lead 34a may not be located along the same straight line in the X-axis direction. This allows the battery diagnostic device 100 to accurately diagnose the location on the Y-axis of an electrode tab 33 where a break has occurred in the electrode tabs 33 stacked in the Y-axis direction.

[0065] According to the embodiment, if the measurement point (e.g., Q2) of the second electrode lead 34b is the same, the multiple measurement points (e.g., P1, P2, and P3) of the first electrode lead 34a can be located along a straight line in the Y-axis direction. Here, the multiple measurement points may include at least two of the first point P1, the second point P2, and / or the third point P3. For example, the first point P1, the second point P2, and the third point P3 can be located along a straight line in the second direction (Y-axis direction) which intersects the first direction (X-axis direction) in which the first electrode lead 34a protrudes from the battery cell 10. Therefore, if the first point is P1, the second point may be P2 and the third point may be P3, and if the first point is P4, the second point may be P5 and the third point may be P6. This allows the battery diagnostic device 100 to accurately diagnose the location on the Y-axis of the electrode tab 33 where a break in the wire has occurred, among the electrode tabs 33 stacked in the Y-axis direction.

[0066] According to the embodiment, the first point P1, the second point P2, and the third point P3 can be located at a predetermined distance apart. According to the embodiment, the first point P1 can be located at a distance of a first interval from the second point P2 in the second direction (Y-axis direction), and the third point can be located at a distance of a first interval from the second point P2 in the direction opposite to the second direction. As a result, the battery diagnostic device 100 can compare the impedances measured at the first point and the third point, which are located at a distance of a first interval above and below the second point among the multiple measurement points, and accurately diagnose the location on the Y-axis where the open electrode tab 33 has occurred. Furthermore, the battery diagnostic device 100 can diagnose the state of the battery cell more accurately than conventional battery diagnostic devices based on the impedance change (i.e., deviation) including the impedance change between the first point and the second point, the impedance change between the second point and the third point, and the impedance change between the first point and the third point, as described later.

[0067] Referring again to Figures 2 and 4, one or more processors 120 can operate the battery diagnostic device 100. For example, one or more processors 120 can process data acquired by the interface 110 to diagnose the state of the battery cell 10. According to the embodiment, one or more processors 120 can determine whether there is an abnormality in the battery cell 10 based on impedance data by frequency acquired by the interface 110 and diagnose its state.

[0068] According to the embodiment, one or more processors 120 can diagnose the state of the battery cell 10 based on impedance and impedance change. Here, impedance may refer to the impedance measured at a specific point on the fixed second electrode lead 34b (e.g., Q2) and at multiple measurement points on the first electrode lead 34a (e.g., P1 and P2). The impedance change may refer to the difference between the aforementioned impedances.

[0069] For example, one or more processors 120 can diagnose the state of the battery cell 10 based on a first impedance Z1, which is the impedance between a first point P1 among multiple measurement points and a specific point (e.g., Q2) on the second electrode lead 34b; a second impedance Z2, which is the impedance between a second point P2 among multiple measurement points and a specific point (e.g., Q2) on the second electrode lead 34b; and a first impedance change amount Z_12, which is the difference between the first impedance Z1 and the second impedance Z2.

[0070] According to the embodiment, one or more processors 120 can compare the first impedance Z1, the second impedance Z2, and the first impedance change Z_12 with predetermined thresholds. Here, the predetermined thresholds refer to the impedance measured in a normal battery cell and may refer to a reference value for distinguishing between a normal battery cell and an abnormal battery cell. For example, the predetermined thresholds may include the threshold for the first impedance Z1, the threshold for the second impedance Z2, and the threshold for the first impedance change Z_12.

[0071] According to the embodiment, one or more processors 120 can determine a predetermined threshold based on the impedance measured at a measurement point of a normal battery cell corresponding to each of a plurality of measurement points of the battery cell 10 under test. For example, one or more processors 120 can determine a predetermined threshold based on the frequency-dependent impedance between the first point P1 of a normal battery cell corresponding to the first point P1 of the battery cell 10 under test and the measurement point of a normal battery cell corresponding to the measurement point of the second electrode lead 34b of the battery cell 10 under test. Here, the predetermined threshold may mean the frequency-dependent impedance range of a normal battery cell. For example, the predetermined threshold may mean the maximum or minimum value of a normal battery cell depending on the frequency. As a result, one or more processors 120 can diagnose a battery cell with a higher impedance than a normal battery cell as an abnormal battery cell.

[0072] Referring to Figure 5, one or more processors 120 can calculate impedance-related parameters according to frequency and diagnose the state of the battery cell 10 based on one or more parameters. Here, impedance-related parameters may include impedance phase angle, resistance, and reactance.

[0073] According to the embodiment, one or more processors 120 can calculate the resistance and reactance of the first impedance Z1, the second impedance Z2, and the first impedance change amount Z_12, and diagnose the state of the battery cell 10 by comparing at least one of the resistance and reactance with a predetermined threshold TH. Here, the predetermined threshold TH may mean a reference value that distinguishes a normal battery cell S1 from an abnormal battery cell S2. For example, the predetermined threshold TH may mean the resistance or reactance calculated based on the impedance measured in a normal battery cell S1. As a result, the battery diagnostic device 100 can diagnose an abnormal battery cell S2 based on at least one of the resistance, which is the real part of the impedance, and the reactance, which is the imaginary part. Furthermore, even if an abnormal battery cell S2 cannot be diagnosed based on resistance, the battery diagnostic device 100 can diagnose an abnormal battery cell S2 based on reactance, thereby improving the accuracy of the diagnosis.

[0074] According to the embodiment, one or more processors 120 can diagnose a battery cell 10 as being in an abnormal state if at least one of the first impedance Z1, the second impedance Z2, and the first impedance change Z_12 is greater than a predetermined threshold TH. Therefore, the battery diagnostic device 100 can improve the accuracy of its diagnosis by further considering the first impedance change Z_12 and comparing it to the threshold TH, compared to comparing the first impedance Z1 or the second impedance Z2 to the threshold TH. For example, if the first impedance Z1 and the second impedance Z2 are within the normal range below the threshold, but the first impedance change Z_12 is greater than the threshold, the battery diagnostic device 100 can diagnose an abnormality in the battery cell and improve the accuracy of its diagnosis. This allows the battery diagnostic device 100 to avoid the problem of an abnormal battery cell S2 being misdiagnosed as a normal battery cell S1 by diagnosing the state of the battery cell 10 based on the impedance measured at one measurement point.

[0075] According to the embodiment, if there are three measurement points on the first electrode lead 34a, one or more processors 120 can diagnose the state of the battery cell 10 based on the impedance and impedance change measured at the multiple measurement points. Here, impedance may refer to the impedance measured at a specific point on the fixed second electrode lead 34b (e.g., Q2) and at each of the multiple measurement points on the first electrode lead 34a (e.g., P1, P2, and P3). The impedance change may refer to the difference between the aforementioned impedances.

[0076] For example, one or more processors 120 can diagnose the state of the battery cell 10 based on the first impedance Z1, the second impedance Z2, the third impedance Z3, the first impedance change Z_12, the second impedance change Z_23, and the third impedance change Z_31. Here, the third impedance Z3 refers to the impedance between the third point P3 and the second electrode lead 34b, the second impedance change Z_23 refers to the difference between the second impedance Z2 and the third impedance, and the third impedance change Z_31 refers to the difference between the first impedance Z1 and the third impedance. As a result, the battery diagnostic device 100 can diagnose the state of the battery cell 10 more accurately when using three measurement points compared to when using two measurement points, by further considering the third impedance, the second impedance change Z_23, and the third impedance change Z_31.

[0077] According to one embodiment, one or more processors 120 can diagnose the location of a defect in the battery cell 10 under inspection based on the sign of the change in impedance. Here, the defect may include a broken tab inside the battery cell 10, a faulty electrode, or lithium deposition.

[0078] For example, if there are two measurement points on the first electrode lead 34a, and a break occurs in the electrode tab 33 closest to the first point P1, then the first impedance Z1 is greater than the second impedance Z2. Therefore, the first impedance change Z_12, which is the difference between the first impedance Z1 and the second impedance Z2, may be a positive number. As a result, one or more processors 120 can diagnose that a tab break has occurred at the first point P1 of the battery cell 10 under test if the first impedance change Z_12 is a positive number.

[0079] In contrast, if a break occurs in the electrode tab 33 closest to the second point P2, the first impedance Z1 is smaller than the second impedance Z2. Therefore, the first impedance change Z_12, which is the difference between the first impedance Z1 and the second impedance Z2, may be a negative number. As a result, one or more processors 120 can diagnose that a tab break has occurred at the second point P2 of the battery cell 10 under inspection if the first impedance change Z_12 is a negative number. Therefore, the battery diagnostic device 100 can not only diagnose whether the battery cell 10 under inspection is an abnormal battery cell or a normal battery cell, but can also diagnose the exact location where a defect has occurred in an abnormal battery cell.

[0080] According to the embodiment, one or more processors 120 can diagnose the extent of a defect based on the magnitude of the impedance or the magnitude of the impedance change. Here, the magnitude of the impedance may mean the value obtained by adding the squares of the real and imaginary parts of the impedance and then taking the square root. For example, one or more processors 120 can diagnose that the extent of a defect in the battery cell 10 under inspection is greater the greater any one of the magnitudes of the first impedance Z1, the second impedance Z2, and the first impedance change Z12 is greater than a predetermined threshold. Here, the extent of the defect may mean the length of the electrode tab break inside the battery cell 10, the area of ​​the electrode defect, or the extent (e.g., amount) of lithium deposition.

[0081] According to the embodiment, one or more processors 120 can diagnose the extent of a defect based on impedance resistance or impedance reactance. For example, one or more processors 120 can diagnose that the greater the impedance resistance or impedance reactance is above a predetermined threshold, the greater the extent of the defect in the battery cell 10 under inspection. Here, the predetermined threshold may mean a reference value that distinguishes a normal battery cell from an abnormal battery cell.

[0082] According to various embodiments, the magnitude of the impedance tends to increase as the length of the break in the electrode tab 33 increases. For example, the resistance can increase as the length of the break increases. Therefore, the battery diagnostic device 100 can diagnose the length of the break based on the magnitude of the impedance.

[0083] According to the embodiment, if the diagnostic results confirm that there is an abnormality in the battery cell 10, the battery diagnostic device 100 can provide the user with information about the abnormal battery cell. For example, one or more processors 120 can provide information about the abnormal battery cell to a user terminal via a communication circuit (not shown), and can also provide information about the abnormal battery cell via a display provided in the vehicle or charger, etc.

[0084] Figure 6 is a flowchart showing the operation of a battery diagnostic device according to one embodiment disclosed in this document. Referring to Figure 6, the battery diagnostic device 100 acquires the impedance based on the frequency of the voltage applied between each of the multiple measurement points on the first electrode lead of the battery cell under inspection and the second electrode lead of the battery cell (S101). Based on the first impedance, which is the impedance between the first of the multiple measurement points and the second electrode lead, the second impedance, which is the impedance between the second of the multiple measurement points and the second electrode lead, and the first impedance change amount, which is the difference between the first impedance and the second impedance, the state of the battery cell can be diagnosed (S102).

[0085] In step S101, the interface 110 of the battery diagnostic device 100 can acquire the impedance based on the frequency of the voltage applied between each of the multiple measurement points on the first electrode lead of the battery cell under inspection and the second electrode lead of the battery cell (S101). Here, the interface 110 can acquire impedance data from the impedance measuring device 150 or the BMS 20.

[0086] In step S102, one or more processors 120 of the battery diagnostic device 100 can diagnose the state of the battery cell based on the first impedance, the second impedance, and the change in the first impedance (S102). According to the embodiment, if there are three measurement points on the first electrode lead, one or more processors 120 can further diagnose the state of the battery cell based on the third impedance, which is the impedance between the third measurement point and the second electrode lead, the change in the second impedance, which is the difference between the second impedance and the third impedance, and the change in the third impedance, which is the difference between the first impedance and the third impedance.

[0087] Figure 7 is a block diagram showing the hardware configuration of a computing system for performing the operation method of a battery diagnostic device according to one embodiment disclosed in this document.

[0088] Referring to Figure 7, the computing system 200 according to one embodiment disclosed in this document may include an MCU 210, a memory 220, an input / output I / F 230, and a communication I / F 240.

[0089] The MCU210 may be a processor that executes various programs stored in the memory 220 (for example, a battery cell data acquisition program, a graph calculation program, a data analysis program, a data decomposition algorithm, a normalization program, and a battery cell diagnostic program), processes various information including battery cell characteristic data and latent variables through such programs, and performs the functions of the battery diagnostic device 100 shown in Figures 1 to 6 above.

[0090] Memory 220 can store various programs such as a battery cell data acquisition program, a graph calculation program, a data analysis program, a data decomposition algorithm, a normalization program, and a battery cell diagnostic program.

[0091] Multiple such memories 220 may be provided as needed. The memories 220 may be volatile or non-volatile. As volatile memory, RAM, DRAM, SRAM, etc., can be used. As non-volatile memory, ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc., can be used. The examples of memories 220 listed above are merely illustrative and the system is not limited to these examples.

[0092] The input / output interface 230 can provide an interface that connects input devices (not shown), such as keyboards, mice, and touch panels, with output devices (not shown), such as displays, and the MCU 210, enabling data transmission and reception.

[0093] The communication interface 240 is configured to send and receive various data with the server and may be various devices that support wired or wireless communication. For example, the battery diagnostic device 100 can send and receive various information, including the shape model of the battery cell, from a separately provided external server via the communication interface 240.

[0094] Thus, the computer program according to one embodiment disclosed in this document may be stored in memory 220 and processed by MCU 210 to be implemented as a module that performs, for example, the functions shown in Figure 2.

[0095] Although all components constituting the embodiments disclosed in this document have been described as operating either as a single unit or in combination, the embodiments disclosed in this document are not necessarily limited to such embodiments. That is, within the scope of the purpose of the embodiments disclosed in this document, all components may operate in combination of one or more units.

[0096] Furthermore, terms such as “includes,” “constitutes,” or “possesses,” as described above, mean that they may contain the component in question, and not exclude other components, unless otherwise specified. All terms, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which the embodiments disclosed herein belong, unless otherwise specified. Commonly used terms, such as those defined in dictionaries, should be interpreted to be consistent with their meaning in the context of the relevant technology, and not to be interpreted in an ideal or overly formal sense unless explicitly defined herein.

[0097] The aforementioned disclosures outline the features of several embodiments so that those skilled in the art may better understand the aspects of this disclosure. Those skilled in the art will understand that this disclosure can be readily used as a basis for designing or modifying other structures to achieve the same purpose or benefits as the embodiments introduced herein. Furthermore, those skilled in the art will recognize that such equivalent configurations do not deviate from the scope of this disclosure, and that various changes, substitutions, and modifications are possible within this specification without departing from the scope of this disclosure. [Explanation of Symbols]

[0098] 1: Battery pack 2: Higher-level controller 10: Battery cell 12: Battery Unit 14: Sensor section 16: Switching section 20: BMS 100: Battery diagnostic device 110: Interface 120:1 or more processors 150: Impedance measuring device 200: Computing Systems 210: MCU 220: Memory 230: Input / Output Interface 240: Communication I / F

Claims

1. An interface for acquiring impedance based on the frequency of the voltage applied between each of multiple measurement points on the first electrode lead of the battery cell under test and the second electrode lead of the battery cell under test, One or more processors that diagnose the state of the battery cell under inspection based on a first impedance, which is the impedance between a first measurement point and the second electrode lead; a second impedance, which is the impedance between a second measurement point and the second electrode lead; and a first impedance change amount, which is the difference between the first impedance and the second impedance. Battery diagnostic device, including

2. The battery diagnostic device according to claim 1, wherein the first point and the second point are located apart in a second direction which intersects with a first direction which is the direction in which the first electrode lead protrudes from the battery cell under inspection.

3. The battery diagnostic device according to claim 2, wherein the first point and the second point are located along a straight line in the second direction.

4. The one or more processors described above are: The first impedance, the second impedance, and the change in the first impedance are compared with predetermined thresholds. The battery diagnostic device according to claim 1, which diagnoses the battery cell under inspection as being in an abnormal state if at least one of the first impedance, the second impedance, and the amount of change of the first impedance is greater than the predetermined threshold.

5. The one or more processors described above are: The battery diagnostic device according to claim 4, wherein the predetermined threshold is determined based on the impedance at the frequency measured at the first point of a normal battery cell corresponding to the first point and the second point of a normal battery cell corresponding to the second point.

6. The one or more processors described above are: A battery diagnostic device according to any one of claims 1 to 5, which diagnoses the state of the battery cell under inspection based on a third impedance, which is the impedance between a third point among the plurality of measurement points and the second electrode lead; a second impedance change, which is the difference between the second impedance and the third impedance; and a third impedance change, which is the difference between the first impedance and the third impedance.

7. The first point is located at a distance of a first interval from the second point in a second direction which intersects with the first direction in which the first electrode lead protrudes from the battery cell under inspection, The battery diagnostic device according to claim 6, wherein the third point is located at a distance of the first interval from the second point in the direction opposite to the second direction.

8. The one or more processors described above are: A battery diagnostic device according to any one of claims 1 to 5, which diagnoses the location where a defect has occurred in the battery cell under inspection based on the sign of the first impedance change amount.

9. The one or more processors described above are: If the first impedance change is a positive number, it is diagnosed that a defect has occurred at the first point of the battery cell under inspection. The battery diagnostic device according to claim 8, which diagnoses that a defect has occurred at the second point of the battery cell under inspection if the first impedance change is a negative number.

10. The one or more processors described above are: The battery diagnostic device according to claim 4 or 5, wherein the greater one of the magnitude of the first impedance, the magnitude of the second impedance, and the magnitude of the change in the first impedance is greater than the predetermined threshold, the greater the degree to which a defect has occurred in the battery cell under inspection.

11. A step of obtaining the impedance based on the frequency of the voltage applied between each of several measurement points on the first electrode lead of the battery cell under test and the second electrode lead of the battery cell under test, A step of diagnosing the state of the battery cell under inspection based on a first impedance, which is the impedance between a first measurement point and the second electrode lead; a second impedance, which is the impedance between a second measurement point and the second electrode lead; and a first impedance change amount, which is the difference between the first impedance and the second impedance. A method for operating a battery diagnostic device, including the operation of the battery diagnostic device.

12. The method of operating the battery diagnostic device according to claim 11, wherein the first point and the second point are located apart in a second direction which intersects with a first direction which is the direction in which the first electrode lead protrudes from the battery cell to be inspected.

13. The method of operating the battery diagnostic device according to claim 12, wherein the first point and the second point are located along a straight line in the second direction.

14. The diagnostic steps described above are: A step of comparing the first impedance, the second impedance, and the amount of change in the first impedance with a predetermined threshold, A method for operating a battery diagnostic device according to claim 11, comprising the step of diagnosing the battery cell under inspection as being in an abnormal state if at least one of the first impedance, the second impedance, and the amount of change of the first impedance is greater than the predetermined threshold.

15. The diagnostic steps described above are: A method for operating a battery diagnostic device according to claim 14, comprising the step of determining a predetermined threshold based on the impedance at the frequency measured at the first point of a normal battery cell corresponding to the first point and the second point of a normal battery cell corresponding to the second point.

16. The diagnostic steps described above are: A method for operating a battery diagnostic device according to any one of claims 11 to 15, further comprising diagnosing the state of the battery cell under inspection based on a third impedance, which is the impedance between a third point among the plurality of measurement points and the second electrode lead; a second impedance change amount, which is the difference between the second impedance and the third impedance; and a third impedance change amount, which is the difference between the first impedance and the third impedance.

17. The first point is located at a distance of a first interval from the second point in a second direction which intersects with the first direction in which the first electrode lead protrudes from the battery cell under inspection, The method of operating a battery diagnostic device according to claim 16, wherein the third point is located at a distance of the first interval from the second point in the direction opposite to the second direction.

18. The diagnostic steps described above are: A method for operating a battery diagnostic device according to any one of claims 11 to 15, comprising the step of diagnosing the location where a defect has occurred in the battery cell under inspection based on the sign of the first impedance change.

19. The step of diagnosing the location where the defect occurred is: If the first impedance change is a positive number, it is diagnosed that a defect has occurred at the first point of the battery cell under inspection. The method of operating the battery diagnostic device according to claim 18, wherein if the first impedance change is a negative number, it is diagnosed that a defect has occurred at the second point of the battery cell under inspection.

20. The diagnostic steps described above are: A method for operating a battery diagnostic device according to claim 14 or 15, wherein the greater one of the magnitude of the first impedance, the magnitude of the second impedance, and the magnitude of the change in the first impedance is greater than the predetermined threshold, the greater the degree to which a defect has occurred in the battery cell under inspection.

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