Battery diagnosis apparatus and operation method thereof

Abstract

A battery diagnosis apparatus according to one embodiment disclosed herein may comprise: a sensor which acquires the voltage value of each of battery cells; and a processor which calculates the cell voltage deviation of each of the battery cells on the basis of the voltage values and the average voltage value of the battery cells, calculates a moving average of the cell voltage deviations on the basis of the cell voltage deviations, calculates a low voltage period on the basis of the moving average, and diagnoses whether the battery cells are abnormal on the basis of the moving average and the low voltage period.

Description

Battery diagnostic device and method of operation thereof

[0001] Cross-citation with related applications

[0002] This invention claims the benefit of priority from Korean Patent Application No. 10-2023-0122554, filed September 14, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] Embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

[0005] Recently, active research and development has been conducted on secondary batteries. The term "secondary battery" refers to a rechargeable battery, encompassing both conventional Ni / Cd and Ni / MH batteries, as well as more recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries boast a significantly higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them a popular power source for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, drawing attention as a next-generation energy storage medium.

[0006] As the industrial sector utilizing batteries expands, battery management systems (BMSs), which diagnose battery safety, are also evolving. BMSs utilize various diagnostic algorithms to assess battery performance and perform appropriate control based on battery condition. Typically, battery packs contain multiple battery cells, and BMSs can detect abnormal cells with excessively low capacities.

[0007] Typically, BMS detects abnormal battery cells by using the voltage drop rate per unit period based on the voltage value of each battery cell.

[0008] However, for abnormal battery cells with a small degree of internal short circuit, the voltage value drops slowly over a long period of time, which can lead to the BMS misdiagnosing the cell as a normal battery cell. Consequently, the accuracy of detecting abnormal battery cells is reduced.

[0009] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0010] A battery diagnostic device according to an embodiment disclosed in this document may include a sensor that acquires a voltage value of each battery cell; and a processor that calculates a cell voltage deviation of each battery cell based on the voltage value and an average voltage value of the battery cells, calculates a moving average of the cell voltage deviation based on the cell voltage deviation, calculates a low voltage period based on the moving average, and diagnoses whether the battery cells are abnormal based on the moving average and the low voltage period.

[0011] In one embodiment, the cell voltage deviation may include a first cell voltage deviation, which is the cell voltage deviation at the current time, and a second cell voltage deviation, which is the cell voltage deviation at a previous time, and the moving average may include a first moving average, which is the moving average of the cell voltage deviation at the current time, and a second moving average, which is the moving average of the cell voltage deviation at a previous time.

[0012] In one embodiment, the processor may calculate the first moving average based on the first cell voltage deviation and the second moving average.

[0013] In one embodiment, the processor may calculate a moving average change amount based on a difference between the first moving average and the second moving average, calculate a time change amount between a point in time corresponding to the first cell voltage deviation and a point in time corresponding to the second cell voltage deviation, and calculate the low voltage period based on the moving average change amount and the time change amount.

[0014] In one embodiment, the processor may calculate the low voltage period based on a comparison result between the moving average change amount and a reference value.

[0015] In one embodiment, the low-voltage period may include a first low-voltage period, which is the low-voltage period at the current time, and a second low-voltage period, which is the low-voltage period at a previous time.

[0016] In one embodiment, the processor may calculate the first low-voltage period by adding the time change amount to the second low-voltage period when the moving average change amount is greater than or equal to the reference value.

[0017] In one embodiment, the processor may calculate the first low voltage period by subtracting the time change amount from the second low voltage period when the moving average change amount is less than the reference value.

[0018] In one embodiment, the processor may calculate a threshold range based on the moving average and the low voltage period, and diagnose a battery cell in which the low voltage period according to the moving average falls within the threshold range as an abnormal battery cell.

[0019] In one embodiment, the average voltage value may be an average of voltage values ​​of battery module units each including the battery cells.

[0020] An operating method of a battery diagnosis device according to an embodiment disclosed in this document may include: obtaining a voltage value of each battery cell; calculating a cell voltage deviation of each battery cell based on the voltage value and an average voltage value of the battery cells; calculating a moving average of the cell voltage deviation based on the cell voltage deviation; calculating a low voltage period based on the moving average; and diagnosing whether the battery cells are abnormal based on the moving average and the low voltage period.

[0021] In one embodiment, the cell voltage deviation may include a first cell voltage deviation, which is the cell voltage deviation at the current time, and a second cell voltage deviation, which is the cell voltage deviation at a previous time, and the moving average may include a first moving average, which is the moving average of the cell voltage deviation at the current time, and a second moving average, which is the moving average of the cell voltage deviation at a previous time.

[0022] In one embodiment, the operation of calculating the moving average may calculate the first moving average based on the first cell voltage deviation and the second moving average.

[0023] In one embodiment, the operation of calculating the low voltage period may include calculating a moving average change amount based on a difference between the first moving average and the second moving average, calculating a time change amount between a point in time corresponding to the first cell voltage deviation and a point in time corresponding to the second cell voltage deviation, and calculating the low voltage period based on the moving average change amount and the time change amount.

[0024] In one embodiment, the operation of calculating the low voltage period may calculate the low voltage period based on a comparison result between the moving average change amount and a reference value.

[0025] In one embodiment, the low-voltage period may include a first low-voltage period, which is the low-voltage period at the current time, and a second low-voltage period, which is the low-voltage period at a previous time.

[0026] In one embodiment, the operation of calculating the low voltage period may calculate the first low voltage period by adding the time change amount to the second low voltage period when the moving average change amount is greater than or equal to the reference value.

[0027] In one embodiment, the operation of calculating the low voltage period may calculate the first low voltage period by subtracting the time change amount from the second low voltage period when the moving average change amount is less than the reference value.

[0028] In one embodiment, the diagnosing operation may calculate a critical range based on the moving average and the low voltage period, and diagnose a battery cell in which the low voltage period according to the moving average is included in the critical range as an abnormal battery cell.

[0029] In one embodiment, the average voltage value may be an average of voltage values ​​of battery module units each including the battery cells.

[0030] The battery diagnostic device and its operating method according to various embodiments disclosed in this document can detect an abnormal battery cell whose voltage value gradually decreases over a long period of time based on various variables calculated based on the voltage value of each battery cell.

[0031] The effects of the battery diagnostic device and the operating method thereof according to the disclosure of this document are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art according to the disclosure of this document.

[0032] FIG. 1 illustrates a battery pack according to one embodiment disclosed in this document.

[0033] FIG. 2 illustrates a block diagram of a battery diagnostic device according to an embodiment disclosed in this document.

[0034] FIG. 3 illustrates a battery diagnostic device for diagnosing a battery pack from outside the battery pack according to one embodiment disclosed in this document.

[0035] FIG. 4 is a graph for SOC-OCV according to one embodiment disclosed in this document.

[0036] FIG. 5 illustrates the cell voltage deviation of each battery cell according to one embodiment disclosed in this document.

[0037] FIG. 6 illustrates a moving average of cell voltage deviation according to one embodiment disclosed in this document.

[0038] FIG. 7 is a graph of a time-moving average and a time-low voltage period according to one embodiment disclosed in this document.

[0039] FIG. 8 illustrates a threshold range based on a moving average and a low voltage period according to an embodiment disclosed in this document.

[0040] FIG. 9 is a flowchart illustrating an operation method of a battery diagnostic device according to an embodiment disclosed in this document.

[0041] FIG. 10 is a flowchart illustrating a detailed operation method of operation 906 according to one embodiment disclosed in this document.

[0042] FIG. 11 is a flowchart illustrating a detailed operation method of operation 908 according to one embodiment disclosed in this document.

[0043] In connection with the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0044] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention encompasses various modifications, equivalents, and / or alternatives of the embodiments.

[0045] The embodiments and terminology used in this document are not intended to limit the technical features described in this document to a specific embodiment, but should be understood to encompass various modifications, equivalents, or alternatives of the embodiment. In connection with the description of the drawings, similar reference numerals may be used to refer to similar or related components. The singular form of a noun corresponding to an item may include one or more of the item, unless the relevant context clearly indicates otherwise.

[0046] In this document, the phrases "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" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", "first", "second", "A", "B", "(a)", or "(b)" may be used merely to distinguish the corresponding component from other corresponding components, and do not limit the corresponding components in any other respect (e.g., importance or order) unless specifically stated otherwise.

[0047] In this document, when a component (e.g., a first component) is referred to as being “connected,” “coupled,” or “connected,” with or without the terms “functionally” or “communicatively,” or “coupled” or “connected,” it means that the component can be connected to the other component directly (e.g., wired or wirelessly), or indirectly (e.g., via a third component).

[0048] The methods according to various embodiments disclosed in this document may be provided as included 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 a machine-readable storage medium (e.g., compact disc read-only memory, CD-ROM), or may be distributed online (e.g., downloaded or uploaded) through 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 temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0049] According to the embodiments disclosed in this document, each component (e.g., a module or a program) of the above-described components may include one or more entities, and some of the entities may be separated and placed in other components. According to the embodiments disclosed in this document, one or more components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., a module or a program) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to the embodiments disclosed in this document, the 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.

[0050] FIG. 1 illustrates a battery pack according to one embodiment disclosed in this document.

[0051] Referring to FIG. 1, a battery pack (1) may include a plurality of battery modules (11, 12, 13) and a battery diagnostic device (100). A first battery module (11) may include a plurality of battery cells (111, 112, 113). In FIG. 1, only the battery cells (111, 112, 113) included in the first battery module (11) are illustrated, but the second battery module (12) and the third battery module (13) may also include a plurality of battery cells. Hereinafter, the description will be based on the plurality of battery cells (111, 112, 113) included in the first battery module (11), but this may also be applied equally to the plurality of battery cells included in the second battery module (12) and the third battery module (13).

[0052] The battery diagnostic device (100) can obtain the voltage value of each of the battery cells (111, 112, 113). The battery diagnostic device (100) can obtain the voltage value of each of the battery cells (111, 112, 113) in a specified SOC range. Here, the voltage value may be an open circuit voltage (OCV) value, and the following description assumes that the voltage value is an open circuit voltage value.

[0053] The battery diagnosis device (100) can calculate the cell voltage deviation of each of the battery cells (111, 112, 113). The battery diagnosis device (100) can calculate the cell voltage deviation of each of the battery cells based on the voltage value of each of the battery cells (111, 112, 113) and the average voltage value of the battery cells (111, 112, 113). Here, the cell voltage deviation may be a value obtained by subtracting the average voltage value of all or part of the entire battery cells from the voltage value of each of the battery cells (111, 112, 113). The cell voltage deviation may include a first cell voltage deviation, which is a cell voltage deviation at a current time, and a second cell voltage deviation, which is a cell voltage deviation at a previous time.

[0054] In one embodiment, the battery diagnosis device (100) can calculate the cell voltage deviation for each battery module. The battery diagnosis device (100) can calculate the cell voltage deviation for each of the battery cells (111, 112, 113) based on the average voltage value of the first battery module (11). Similarly, the battery diagnosis device (100) can calculate the cell voltage deviation for each of the battery cells included in the second battery module (12) based on the average voltage value of the battery cells included in the second battery module (12).

[0055] The battery diagnostic device (100) can calculate a moving average of cell voltage deviations based on cell voltage deviations. Here, the moving average of cell voltage deviations can be calculated based on cell voltage deviations at at least two points in time. The moving average can include a first moving average, which is a moving average of the current point in time, and a second moving average, which is a moving average of a previous point in time.

[0056] The battery diagnostic device (100) can calculate a low-voltage period based on a moving average of cell voltage deviations. Here, the low-voltage period may be a cumulative period of time during which an internal short circuit occurs in a battery cell and the moving average of cell voltage deviations is lower than a specified threshold value. The low-voltage period may include a first low-voltage period, which is a low-voltage period at the current time, and a second low-voltage period, which is a low-voltage period at a previous time.

[0057] The battery diagnostic device (100) can diagnose whether battery cells (111, 112, 113) are abnormal based on the moving average and low voltage period.

[0058] In one embodiment, the battery diagnostic device (100) may be included in a BMS capable of diagnosing a battery pack (1), and operations performed in the battery diagnostic device (100) may be performed in the BMS. In addition, the operations of the battery diagnostic device (100) may be performed by a BMS in a vehicle, as well as in various devices such as a server, a cloud charger, or a charger / discharger.

[0059] FIG. 2 illustrates a block diagram of a battery diagnostic device according to an embodiment disclosed in this document.

[0060] Referring to FIG. 2, the battery diagnostic device (100) may include a sensor (102), a memory (104), a processor (106), and a communication circuit (108). According to an embodiment, the battery diagnostic device (100) illustrated in FIG. 2 may further include at least one component (e.g., a display, an input device, or an output device) other than the components illustrated in FIG. 2.

[0061] The sensor (102) can obtain values ​​related to the status of the battery cells (111, 112, 113). In one embodiment, the values ​​related to the status may represent one or more values ​​for voltage, current, resistance, state of charge (SOC), state of health (SOH), temperature, or a combination thereof of each of the battery cells (111, 112, 113). Hereinafter, the values ​​related to the status may be referred to as 'status values'.

[0062] In one embodiment, the sensor (102) can obtain the voltage value of each of the battery cells (111, 112, 113) for a specified time or according to a specified cycle.

[0063] In one embodiment, the sensor (102) may not be included in the battery diagnostic device (100) if the operations performed in the battery diagnostic device (100) are implemented in a server, cloud charger, or charger / discharger.

[0064] The memory (104) may include volatile memory and / or non-volatile memory.

[0065] In one embodiment, the memory (104) may include one or more software.

[0066] In one embodiment, the memory (104) may store data used by at least one component (e.g., the processor (106)) of the battery diagnostic device (100). For example, the data may include software (or instructions related thereto), input data, or output data. In one embodiment, the instructions, when executed by the processor (106), may cause the battery diagnostic device (100) to perform operations defined by the instructions.

[0067] The processor (106) can calculate the cell voltage deviation of each of the battery cells (111, 112, 113). The processor (106) can calculate the cell voltage deviation of each of the battery cells (111, 112, 113) based on the voltage value of each of the battery cells (111, 112, 113) and the average voltage value of the battery cells. Here, the cell voltage deviation can be calculated based on the difference between the voltage value of each of the battery cells (111, 112, 113) and the average voltage value of the voltage values ​​of the battery cells (111, 112, 113). The cell voltage deviation can include a first cell voltage deviation, which is a cell voltage deviation at a current time point, and a second cell voltage deviation, which is a cell voltage deviation at a previous time point.

[0068] In one embodiment, the processor (106) may calculate the cell voltage deviation of each of the battery cells included in the battery pack (1). For example, the processor (106) may calculate the cell voltage deviation of each of the battery cells based on the difference between the voltage value of each of the battery cells and the average voltage value of the battery cells.

[0069] In one embodiment, the processor (106) can calculate the cell voltage deviation for each battery module. The processor (106) can calculate the cell voltage deviation for each of the battery cells (111, 112, 113) constituting the first battery module (11) based on the difference between the voltage value of each of the battery cells (111, 112, 113) and the average voltage value of the battery cells (111, 112, 113).

[0070] The processor (106) can calculate a moving average of cell voltage deviations. The processor (106) can calculate the first moving average of the current time point based on the first cell voltage deviation, which is the cell voltage deviation of the current time point, and the second moving average calculated at the previous time point. Here, the current time point is a term to distinguish it from the previous time point, and does not necessarily mean only the present in real time, but can also refer to a specific time point in the past compared to the present in real time. The processor (106) can calculate the first moving average using a weighted moving average. The processor (106) can calculate the first moving average based on a value obtained by multiplying each of the first cell voltage deviation and the second moving average by a specified weight. The first moving average can be expressed by mathematical equation 1.

[0071] [Mathematical Formula 1]

[0072] 1st moving average = 2nd moving average * (1-weight) + 1st cell voltage deviation * weight

[0073] Here, the weight can be any value within the range of 0 to 1.

[0074] The processor (106) can calculate a low voltage period based on a moving average. Here, the low voltage period can include a first low voltage period at the current time and a second low voltage period at a previous time.

[0075] The processor (106) can calculate the first low voltage period based on the amount of change in the moving average and the amount of change over time. Here, the amount of change in the moving average can be calculated based on the first moving average and the second moving average. The amount of change over time can be calculated based on the difference between the current point in time and the previous point in time. The amount of change over time can be calculated based on the difference between the point in time corresponding to the first cell voltage deviation and the point in time corresponding to the second cell voltage deviation.

[0076] The processor (106) can calculate a moving average change amount based on the first moving average and the second moving average. Here, the moving average change amount can be calculated based on the difference between the first moving average calculated at the current time and the second moving average calculated at the previous time.

[0077] The processor (106) may calculate a low voltage period based on the result of comparing the moving average change amount with the reference value. In one embodiment, if the moving average change amount is greater than or equal to the reference value, the processor (106) may calculate a first low voltage period at the current time by adding the time change amount to the second low voltage period calculated at the previous time. If the moving average change amount is less than the reference value, the processor (106) may calculate a first low voltage period at the current time by subtracting the time change amount from the second low voltage period calculated at the previous time.

[0078] The processor (106) can diagnose whether the battery cells (111, 112, 113) are abnormal based on the moving average and the low voltage period. In one embodiment, the processor (106) can calculate a critical range based on the moving average and the low voltage period. Here, the critical range may be a coordinate value corresponding to the low voltage period according to the moving average. Details regarding the critical range will be described later in FIG. 8.

[0079] The processor (106) can diagnose a battery cell in which a low voltage period according to a moving average falls within a critical range as an abnormal battery cell. The processor (106) can diagnose a battery cell in which a first low voltage period according to a first moving average falls within a critical range as an abnormal battery cell.

[0080] In one embodiment, the processor (106) may include a central processing unit, an application processor, a graphics processing unit, a neural processing unit (NPU), an image signal processor, a sensor hub processor, or a communication processor.

[0081] In one embodiment, the processor (106) may execute software to control at least one other component (e.g., hardware or software component) of the battery diagnostic device (100) connected to the processor (106) and perform various data processing or calculations.

[0082] The communication circuit (108) can transmit the diagnostic results to a user terminal. Here, the user terminal may be a device that controls the battery diagnostic device (100) and / or receives the diagnostic results from the battery diagnostic device (100). Details regarding the user terminal are described later in FIG. 3.

[0083] In one embodiment, the communication circuit (108) establishes a wired communication channel and / or a wireless communication channel between the battery diagnostic device (100) and the electronic device including the battery pack (1), and can transmit and receive data with the electronic device through the established communication channel. Details regarding the electronic device including the battery pack (1) are described later in FIG. 3.

[0084] In one embodiment, the communication circuit (108) of the battery diagnostic device (100) can establish a wired communication channel and / or a wireless communication channel between the battery diagnostic device (100) and a user terminal and / or electronic device, and transmit and receive data with the user terminal and / or electronic device through the established communication channel.

[0085] FIG. 3 illustrates a battery diagnostic device for diagnosing a battery pack from outside the battery pack according to one embodiment disclosed in this document.

[0086] Referring to FIG. 3, the battery diagnosis device (100) can be connected to an electronic device (30) and / or a user terminal (300) via wired / wireless. Here, the electronic device (30) may be a mobile device (e.g., a mobile phone, a laptop computer, a smart phone, a smart pad), an electric vehicle (e.g., an electric vehicle (EV), a hybrid EV (HEV), a plug-in HEV (PHEV), a fuel cell EV (FCEV)), or an energy storage system (ESS). The user terminal (300) controls the battery diagnosis device (100) or receives a diagnosis result from the battery diagnosis device (100), and may be a mobile device (e.g., a mobile phone, a laptop computer, a smart phone, a smart pad) or a personal computer (PC). In one embodiment, the connection between the battery diagnosis device (100) and the electronic device (30) and / or the user terminal (300) may be a communication connection via a wired and / or wireless network.

[0087] The battery diagnostic device (100) can obtain the voltage values ​​of the battery cells (111, 112, 113). The battery diagnostic device (100) can obtain the voltage values ​​of the battery cells (111, 112, 113) through a wired / wireless network. In this case, the battery diagnostic device (100) may not include a sensor (102) and can obtain the voltage values ​​of the battery cells (111, 112, 113) through a communication circuit (108).

[0088] The battery diagnostic device (100) can transmit the diagnosis results for diagnosing whether the battery cells (111, 112, 113) are abnormal to the user terminal (300). The battery diagnostic device (100) can transmit the diagnosis results for diagnosing whether the battery cells (111, 112, 113) are abnormal to the user terminal (300) through a wired and / or wireless communication channel established through a communication circuit (108). Here, the diagnosis results can include the presence or absence of an abnormal battery cell, a status value for an abnormal battery cell, and / or a diagnosis result for a battery module including an abnormal battery cell.

[0089] In one embodiment, the connection between the battery diagnostic device (100) and the electronic device (30) and / or the user terminal (300) may be a communication connection via a wired and / or wireless network. In one embodiment, the wired network may be based on a local area network (LAN) communication or a power line communication. In one embodiment, the wireless network may be based on a short-range communication network (e.g., Bluetooth, wireless fidelity (WiFi), or infrared data association (IrDA)) or a long-range communication network (cellular network, 4G network, 5G network).

[0090] In one embodiment, the connection between the battery diagnostic device (100) and the electronic device (30) and / or the user terminal (300) may be a connection via a device-to-device communication method (e.g., a bus, a general purpose input and output (GPIO), a serial peripheral interface (SPI), or a mobile industry processor interface (MIPI)).

[0091] FIG. 4 is a graph for SOC-OCV according to one embodiment disclosed in this document.

[0092] Referring to FIG. 4, the graph may include an open circuit voltage (OCV) value according to the SOC of the battery pack (1).

[0093] Referring to the graph, in the case of the second section (402), which is a section corresponding to a relatively high SOC, it can be confirmed that the voltage value according to the SOC rises in a linear manner without abrupt changes compared to the first section (400). In a section including an inflection point or a section showing a rapid increase in the OCV value, a factor of error may occur, such as a difference between the charge OCV value and the discharge OCV value. Accordingly, the battery diagnosis device (100) can generate a more accurate diagnosis result when calculating the cell voltage deviation using the voltage value obtained in the second section (402) where the voltage value rises linearly without abrupt changes.

[0094] FIG. 5 illustrates the cell voltage deviation of each battery cell according to one embodiment disclosed in this document.

[0095] Referring to FIG. 5, the graph may include cell voltage deviations over time for each of the battery cells (111, 112, 113). Here, T1 to T9 are time units, and may refer to points in time that are evenly divided into several hours to several months.

[0096] The battery diagnostic device (100) can calculate the cell voltage deviation based on the voltage value obtained at a specified time or at a specified cycle.

[0097] The battery diagnostic device (100) can calculate a moving average of cell voltage deviations using the calculated cell voltage deviations. For example, the battery diagnostic device (100) can calculate a moving average of cell voltage deviations at time t2 (502) based on the cell voltage deviations for the first battery cell (111) calculated at time t1 (500) and time t2 (502).

[0098] FIG. 6 illustrates a moving average of cell voltage deviation according to one embodiment disclosed in this document.

[0099] Referring to FIG. 6, the graph may include a moving average of cell voltage deviations over time for each of the battery cells (111, 112, 113). The battery diagnostic device (100) may calculate the moving average of the cell voltage deviations based on the cell voltage deviations at at least two points in time (e.g., point t1 (500) and point t2 (502) of FIG. 5). For example, the battery diagnostic device (100) may calculate a second moving average based on a second cell voltage deviation calculated at a previous point in time t1 (500) and a first moving average corresponding to point in time t2 (502) using the aforementioned [Mathematical Formula 1] based on the first cell voltage deviation calculated at point in time t2 (500), for each of the first battery cells (111) to the third battery cells (113).

[0100] FIG. 7 is a graph of a time-moving average and a time-low voltage period according to one embodiment disclosed in this document.

[0101] Referring to FIG. 7, the graph may include a moving average of cell voltage deviation and a low voltage period for each of the battery cells (111, 112, 113).

[0102] Referring to the graph, it can be confirmed that the trend of the moving average and the low voltage period for the second battery cell (112) is that, unlike the first battery cell (111) and the third battery cell (113), the moving average tends to decrease while the low voltage period tends to increase. The battery diagnosis device (100) can diagnose the second battery cell (112) as an abnormal battery cell when the first moving average and the first low voltage period of the current point in time of the second battery cell (112) each exceed a threshold value. Here, the first moving average and the first low voltage period may refer to the most recently calculated ones.

[0103] FIG. 8 illustrates a threshold range based on a moving average and a low voltage period according to an embodiment disclosed in this document.

[0104] Referring to FIG. 8, the graph may include a threshold range (800). The threshold range (800) may be calculated based on threshold values ​​for each moving average and low voltage period. The threshold range (800) may be set by simultaneously considering the current or previously calculated moving averages and low voltage periods.

[0105] Referring to the graph, a battery cell whose first moving average is less than or equal to A can be diagnosed as an abnormal battery cell regardless of the first low voltage period. Here, A and B can be less than or equal to 0, and the absolute value of A can be greater than the absolute value of B. A battery cell whose first moving average is B can be diagnosed as an abnormal battery cell if the first low voltage period is M days or more. A battery cell whose first moving average is greater than or equal to A and less than or equal to B can be diagnosed as an abnormal battery cell if the first low voltage period is more than or equal to a specified threshold number of days. Here, the specified threshold number of days can be a y-axis value on a straight line based on coordinate values ​​(A, N) and (B, M) of the first low voltage period according to the first moving average. The above-mentioned A, B, N, and M can be arbitrary values. For example, if A is -20, B is -7, N is 10, and M is 100, a battery cell having a first moving average of -7 mV can be diagnosed as an abnormal battery cell if the first low voltage period is 100 days or longer, and a battery cell having a first moving average of -20 mV or lower can be diagnosed as an abnormal battery cell regardless of the first low voltage period.

[0106] Referring to FIGS. 7 and 8, the battery diagnosis device (100) can diagnose the second battery cell (112) as an abnormal battery cell if the first low-voltage period according to the first moving average of the second battery cell (112) is included in the critical range (800). On the other hand, the battery diagnosis device (100) can diagnose the first battery cell (111) and the third battery cell (113) as normal battery cells if the first low-voltage period according to the first moving average of each of the first battery cell (111) and the third battery cell (113) is not included in the critical range (800).

[0107] FIG. 9 is a flowchart illustrating an operation method of a battery diagnostic device according to an embodiment disclosed in this document.

[0108] Referring to FIG. 9, in operation 900, the battery diagnostic device (100) can obtain the voltage value of each of the battery cells (111, 112, 113).

[0109] In operation 902, the battery diagnosis device (100) can calculate the cell voltage deviation of each of the battery cells (111, 112, 113). The battery diagnosis device (100) can calculate the cell voltage deviation of each of the battery cells (111, 112, 113) based on the voltage value of each of the battery cells (111, 112, 113) and the average voltage value of the battery cells (111, 112, 113). Here, the average voltage value may be an average value of the voltage values ​​of all battery cells or an average value of the voltage values ​​of a battery module unit.

[0110] In operation 904, the battery diagnostic device (100) can calculate a moving average of cell voltage deviations.

[0111] In operation 906, the battery diagnostic device (100) can calculate the low voltage period based on the moving average.

[0112] In operation 908, the battery diagnostic device (100) can diagnose whether the battery cells (111, 112, 113) are abnormal based on the moving average and the low voltage period.

[0113] FIG. 10 is a flowchart illustrating a detailed operation method of operation 906 according to one embodiment disclosed in this document.

[0114] Referring to FIG. 10, operation 906 illustrated in FIG. 9 may include operations 1000, 1002, and 1004.

[0115] In operation 1000, the battery diagnosis device (100) can calculate a moving average change amount. The battery diagnosis device (100) can calculate the moving average change amount based on a first moving average at the current time and a second moving average at a previous time. The battery diagnosis device (100) can calculate the moving average change amount based on a difference between the first moving average and the second moving average.

[0116] In operation 1002, the battery diagnostic device (100) can calculate the time variation. The battery diagnostic device (100) can calculate the time variation based on a point in time corresponding to the first cell voltage deviation and a point in time corresponding to the second cell voltage deviation. The battery diagnostic device (100) can calculate the time variation based on a difference between a point in time corresponding to the first cell voltage deviation and a point in time corresponding to the second cell voltage deviation.

[0117] In operation 1004, the battery diagnostic device (100) can calculate a low voltage period based on the moving average change amount and the time change amount. The battery diagnostic device (100) can calculate a first low voltage period based on the moving average change amount, the time change amount, and the second low voltage period calculated at a previous point in time.

[0118] FIG. 11 is a flowchart illustrating a detailed operation method of operation 908 according to one embodiment disclosed in this document.

[0119] Referring to FIG. 11, operation 908 illustrated in FIG. 9 may include operations 1100, 1102, 1104, and 1106.

[0120] In operation 1100, the battery diagnostic device (100) can calculate a threshold range (800) based on a moving average and a low voltage period. The battery diagnostic device (100) can calculate the threshold range (800) based on a threshold value for the moving average and a threshold value for the low voltage period. For example, the battery diagnostic device (100) can calculate a threshold value for the moving average based on the moving average of each of the battery cells (111, 112, 113), and can calculate a threshold value for the low voltage period based on the low voltage period of each of the battery cells (111, 112, 113).

[0121] In operation 1102, the battery diagnostic device (100) can determine whether a low voltage period according to a moving average is included in a critical range (800). The battery diagnostic device (100) can determine whether a value corresponding to a first low voltage period according to a first moving average is included in a critical range (800).

[0122] In operation 1104, the battery diagnostic device (100) can diagnose a battery cell in which a low voltage period according to a moving average falls within a critical range (800) as an abnormal battery cell. The battery diagnostic device (100) can diagnose a battery cell in which a first low voltage period according to a first moving average falls within a critical range (800) as an abnormal battery cell.

[0123] In operation 1106, the battery diagnostic device (100) can diagnose a battery cell in which the low voltage period according to the moving average is not included in the critical range (800) as a normal battery cell. The battery diagnostic device (100) can diagnose a battery cell in which the first low voltage period according to the first moving average is not included in the critical range (800) as an abnormal battery cell.

[0124] The terms "include," "comprise," or "have" used herein, unless otherwise specifically stated, imply that the corresponding component may be included, and therefore should be interpreted to include other components rather than to exclude other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as terms defined in dictionaries, should be interpreted to be consistent with their contextual meaning in the relevant art, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

[0125] The above description is merely an example of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document. Therefore, the embodiments disclosed in this document are not intended to limit the technical idea of ​​the embodiments disclosed in this document, but to explain it, and the scope of the technical idea disclosed in this document is not limited by these embodiments. The scope of protection of the technical idea disclosed in this document should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of this document.

Claims

1. A sensor that obtains the voltage value of each battery cell; and Calculate the cell voltage deviation of each of the battery cells based on the voltage value and the average voltage value of the battery cells, Calculate a moving average of the cell voltage deviation based on the cell voltage deviation, Calculate the low voltage period based on the above moving average, A processor that diagnoses whether the battery cells are abnormal based on the moving average and the low voltage period, Battery diagnostic device.

2. In claim 1, The above cell voltage deviation includes a first cell voltage deviation, which is the cell voltage deviation at the current time, and a second cell voltage deviation, which is the cell voltage deviation at the previous time, The above moving average includes a first moving average which is a moving average of the cell voltage deviation at the current point in time and a second moving average which is a moving average of the cell voltage deviation at the previous point in time. Battery diagnostic device.

3. In claim 2, The above processor, Calculating the first moving average based on the first cell voltage deviation and the second moving average, Battery diagnostic device.

4. In claim 2, The above processor, Calculate the moving average change amount based on the difference between the first moving average and the second moving average, Calculate the time change between the time corresponding to the first cell voltage deviation and the time corresponding to the second cell voltage deviation, Calculating the low voltage period based on the moving average change amount and the time change amount, Battery diagnostic device.

5. In claim 4, The above processor, Calculating the low voltage period based on the comparison result of the moving average change amount and the reference value. Battery diagnostic device.

6. In claim 5, The above low voltage period includes the first low voltage period, which is the low voltage period at the present time, and the second low voltage period, which is the low voltage period at the previous time. Battery diagnostic device.

7. In claim 6, The above processor, If the above moving average change amount is greater than or equal to the reference value, the first low-voltage period is calculated by adding the time change amount to the second low-voltage period. Battery diagnostic device.

8. In claim 6, The above processor, If the moving average change amount is less than the reference value, the first low-voltage period is calculated by subtracting the time change amount from the second low-voltage period. Battery diagnostic device.

9. In claim 1, The above processor, Calculate the critical range based on the above moving average and the above low voltage period, A battery cell in which the low voltage period according to the moving average falls within the critical range is diagnosed as an abnormal battery cell. Battery diagnostic device.

10. In claim 1, The above average voltage value is the average of the voltage values ​​of the battery module units each of which includes the battery cells. Battery diagnostic device.

11. An operation to obtain the voltage value of each battery cell; An operation of calculating a cell voltage deviation of each of the battery cells based on the voltage value and the average voltage value of the battery cells; An operation of calculating a moving average of the cell voltage deviation based on the cell voltage deviation; An operation for calculating a low voltage period based on the above moving average; and An operation for diagnosing whether the battery cells are abnormal based on the moving average and the low voltage period, Method of operation of a battery diagnostic device.

12. In claim 11, The above cell voltage deviation includes a first cell voltage deviation, which is the cell voltage deviation at the current time, and a second cell voltage deviation, which is the cell voltage deviation at the previous time, The above moving average includes a first moving average which is a moving average of the cell voltage deviation at the current point in time and a second moving average which is a moving average of the cell voltage deviation at the previous point in time. Method of operation of a battery diagnostic device.

13. In claim 12, The operation of calculating the above moving average is: Calculating the first moving average based on the first cell voltage deviation and the second moving average, Method of operation of a battery diagnostic device.

14. In claim 12, The operation of calculating the above low voltage period is: Calculate the moving average change amount based on the difference between the first moving average and the second moving average, Calculate the amount of time change between the time corresponding to the first cell voltage deviation and the time corresponding to the second cell voltage deviation, Calculating the low voltage period based on the moving average change amount and the time change amount, Method of operation of a battery diagnostic device.

15. In claim 14, The operation of calculating the above low voltage period is: Calculating the low voltage period based on the comparison result of the moving average change amount and the reference value. Method of operation of a battery diagnostic device.

16. In claim 15, The above low voltage period includes the first low voltage period, which is the low voltage period at the present time, and the second low voltage period, which is the low voltage period at the previous time. Method of operation of a battery diagnostic device.

17. In claim 16, The operation of calculating the above low voltage period is: If the above moving average change amount is greater than or equal to the reference value, the first low-voltage period is calculated by adding the time change amount to the second low-voltage period. Method of operation of a battery diagnostic device.

18. In claim 16, The operation of calculating the above low voltage period is: If the moving average change amount is less than the reference value, the first low-voltage period is calculated by subtracting the time change amount from the second low-voltage period. Method of operation of a battery diagnostic device.

19. In claim 11, The above diagnostic action is, Calculate the critical range based on the above moving average and the above low voltage period, A battery cell in which the low voltage period according to the moving average falls within the critical range is diagnosed as an abnormal battery cell. Method of operation of a battery diagnostic device.

20. In claim 11, The above average voltage value is the average of the voltage values ​​of the battery module units each of which includes the battery cells. Method of operation of a battery diagnostic device.

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