Battery diagnostic device and battery diagnostic method

Abstract

A battery diagnostic device, according to one embodiment disclosed in the present document, comprises: an interface for acquiring a capacity profile indicating the voltage relative to the capacity of a battery cell comprising an electrode based on a lithium iron phosphate (LFP) material; and at least one processor. The at least one processor is configured to: obtain a first differential capacity profile indicating a capacity variation of the battery cell relative to a voltage variation of the battery cell; divide the entire voltage range included in the first differential capacity profile into one or more voltage ranges; and identify positive electrode degradation of the battery cell on the basis of a first voltage range among the one or more voltage ranges.

Description

Battery diagnostic device and battery diagnostic method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0142734 filed on October 18, 2024, and includes all contents disclosed in the document of said Korean patent application as part of this specification.

[0003] Technology field

[0004] The embodiments disclosed in this document relate to a battery diagnostic device and a battery diagnostic method.

[0005] The degradation of a battery cell can be composed of the sum of the available lithium loss rate and the positive electrode capacity loss rate. The degradation of the positive electrode of a battery cell can be quantified by identifying changes in one or more peak values ​​in the capacity profile used for battery cell diagnosis. However, in the case of battery cells containing LFP (lithium iron phosphate) material, there is a problem in that quantitative diagnosis of positive electrode degradation is difficult because characteristic peaks do not exist. Therefore, a method may be required to determine the positive electrode degradation of a battery cell by utilizing the voltage related to the positive electrode of the battery cell through differential analysis of the battery cell's capacity profile using the characteristics of the material within the battery cell.

[0006] One objective of the embodiments disclosed in this document is to provide a battery diagnostic device and a battery diagnostic method for identifying the degree of degradation of a material within a battery cell.

[0007] One objective of the embodiments disclosed in this document is to provide a battery diagnostic device and a battery diagnostic method for identifying positive degradation of a battery cell using the slope of a differential capacity profile.

[0008] The technical problems of the embodiments disclosed in this document are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0009] A battery diagnostic device according to one embodiment disclosed in this document includes: an interface for obtaining a capacity profile representing a voltage for the capacity of a battery cell comprising an electrode based on a lithium iron phosphate (LFP) material; and at least one processor, wherein the at least one processor may be configured to obtain a first differential capacity profile representing a change in the capacity of the battery cell for a change in the voltage of the battery cell, divide the entire voltage range included in the first differential capacity profile into one or more voltage ranges, and identify positive electrode degradation of the battery cell based on the first voltage range among the one or more voltage ranges.

[0010] For example, the at least one processor may be configured to identify at least one peak included in the first differential capacity profile, identify the first voltage range including a voltage that exceeds a first voltage value corresponding to the at least one peak among the one or more voltage ranges, and identify positive degradation of the battery cell based on the first voltage range.

[0011] For example, the above at least one processor may be configured to acquire a second differential capacity profile representing a change in capacity of the battery cell with respect to a change in voltage of the battery cell in a BoL (beginning of life) state, identify a first feature interval in which the slope of the second differential capacity profile changes within the first voltage range of the second differential capacity profile, and identify positive degradation of the battery cell depending on whether a second feature interval corresponding to the first feature interval is identified in the first differential capacity profile.

[0012] For example, the at least one processor may be configured to identify positive degradation of the battery cell exceeding a specified degree of degradation when the second feature interval is not identified in the first differential capacity profile.

[0013] For example, the at least one processor may be configured to identify a second voltage value included in the first feature interval in the second differential capacity file and a first differential capacity value corresponding to the second voltage value, identify a third voltage value corresponding to the second voltage value and a second differential capacity value corresponding to the third voltage value in the first differential capacity file, identify positive degradation of the battery cell exceeding the specified degradation level when the ratio of the first differential capacity value and the second differential capacity value exceeds the specified degradation level, and adjust the charging speed for charging the battery cell based on the identification of positive degradation of the battery cell exceeding the specified degradation level.

[0014] For example, the at least one processor may be configured to identify positive degradation of the battery cell that is less than the specified degradation level when the second feature interval is identified in the first differential capacity profile.

[0015] For example, the at least one processor may be configured to identify positive degradation of the battery cell based on the slope of the first differential capacity profile included in the first voltage range.

[0016] For example, the above at least one peak may indicate a phase transition of the negative electrode of the battery cell.

[0017] For example, the at least one processor may be configured to obtain the first differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell according to the one or more voltage ranges based on interpolation.

[0018] A battery diagnostic method according to one embodiment disclosed in this document may include the operation of obtaining a first differential capacity profile representing a change in capacity of a battery cell with respect to a change in voltage of a battery cell including an electrode based on an LFP (lithium iron phosphate) material, the operation of dividing an entire voltage range included in the first differential capacity profile into one or more voltage ranges, and the operation of identifying positive electrode degradation of the battery cell based on the first voltage range among the one or more voltage ranges.

[0019] For example, the operation of identifying positive degradation of the battery cell may include the operation of identifying at least one peak included in the first differential capacity profile, the operation of identifying the first voltage range including a voltage that exceeds a first voltage value corresponding to the at least one peak among the one or more voltage ranges, and the operation of identifying positive degradation of the battery cell based on the first voltage range.

[0020] For example, the operation of identifying positive degradation of the battery cell may include the operation of obtaining a second differential capacity profile representing a change in capacity of the battery cell with respect to a change in voltage of the battery cell in the BoL (beginning of life) state, the operation of identifying a first feature section in which the slope of the second differential capacity profile changes within the first voltage range of the second differential capacity profile, and the operation of identifying positive degradation of the battery cell depending on whether a second feature section corresponding to the first feature section is identified in the first differential capacity profile.

[0021] For example, the operation of identifying positive degradation of the battery cell may further include the operation of identifying positive degradation of the battery cell exceeding a specified degree of degradation when the second feature interval is not identified in the first differential capacity profile.

[0022] For example, the operation of identifying positive degradation of the battery cell exceeding the specified degradation degree may further include: an operation of identifying a second voltage value included in the first feature interval in the second differential capacity file and a first differential capacity value corresponding to the second voltage value; an operation of identifying a third voltage value corresponding to the second voltage value and a second differential capacity value corresponding to the third voltage value in the first differential capacity file; an operation of identifying positive degradation of the battery cell exceeding the specified degradation degree when the ratio of the first differential capacity value and the second differential capacity value exceeds the specified degradation degree; and an operation of adjusting the charging speed for charging the battery cell based on identifying positive degradation of the battery cell exceeding the specified degradation degree.

[0023] For example, the operation of identifying positive degradation of the battery cell may further include the operation of identifying positive degradation of the battery cell that is less than the specified degradation degree when the second feature interval is identified in the first differential capacity profile.

[0024] The battery diagnostic device and battery diagnostic method disclosed in this document can identify the degree of degradation of materials within a battery cell.

[0025] The battery diagnostic device and battery diagnostic method disclosed in this document can identify positive degradation of a battery cell using the slope of a differential capacity profile.

[0026] In addition, various effects that can be identified directly or indirectly through this document may be provided.

[0027] FIG. 1 is a block diagram showing a battery pack according to one embodiment disclosed in this document.

[0028] FIG. 2 is a block diagram showing the configuration of a battery diagnostic device according to one embodiment disclosed in this document.

[0029] FIG. 3 illustrates an example of a graph showing data related to a battery cell obtained by a battery diagnostic device according to an embodiment disclosed in this document.

[0030] FIG. 4 illustrates an example of a graph showing a differential capacity profile obtained by a battery diagnostic device according to an embodiment disclosed in this document.

[0031] FIG. 5 illustrates an example of a graph showing a differential capacity profile according to the discharge of a battery cell according to an embodiment disclosed in this document.

[0032] FIG. 6 illustrates an example of a flowchart showing the operation performed by a battery diagnostic device according to an embodiment disclosed in this document.

[0033] FIG. 7 shows a computing system that executes a battery diagnostic method according to one embodiment disclosed in this document.

[0034] Some embodiments disclosed herein are described below with reference to the various embodiments of the accompanying drawings. However, this is not intended to limit the technology to specific embodiments and should be understood to include various modifications, equivalents, and / or alternatives to embodiments of the technology.

[0035] It should be noted that when assigning reference numerals to the components of each drawing, the same components are assigned the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the various embodiments disclosed in this document, if it is determined that a detailed description of related known configurations or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted. The singular form of a noun corresponding to an item may include one or more items unless the relevant context clearly indicates otherwise.

[0036] In describing the components of the embodiments of this document, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended merely to distinguish the components from other components and do not limit the essence, order, or sequence of the components. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments disclosed in this document pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0037] Additionally, in this disclosure, expressions of "greater than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled; however, this is merely for the purpose of expressing an example and does not exclude descriptions of "greater than" or "less than." Conditions described as "greater than" may be replaced with "greater than," conditions described as "less than" may be replaced with "less than," and conditions described as "greater than and less than" may be replaced with "greater than and less than." Furthermore, "A" to "B" below refer to at least one of the elements from A (including A) to B (including B).

[0038] In this document, each of the phrases 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 in the corresponding phrase, or all possible combinations thereof.

[0039] In this document, where any component (e.g., 1) is referred to as being “connected,” “coupled,” or “joined” to another component (e.g., 2), with or without the terms “functionally” or “communicationally,” or where it is referred to as “coupled” or “connected,” it means that the component may be connected to the other component directly (e.g., via a wire), wirelessly, or through a third component.

[0040] As used in one embodiment of this document, the term “module” may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be a component formed integrally, or a minimum unit of said component or a part thereof that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0041] One embodiment of this document may be implemented as software (e.g., a program) comprising one or more instructions stored on a storage medium readable by a machine. For example, the processor of the machine may call at least one of the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The storage medium readable by a machine may be provided in the form of a non-transitory storage medium. Here, "non-transitory" simply means that the storage medium is a tangible device and does not contain a signal, and this term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily in the storage medium.

[0042] According to one embodiment, the method according to the various embodiments disclosed herein may be provided as included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) 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 created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0043] According to various embodiments, each component (e.g., module or program) of the described components may include a singular or multiple entities, and some of the multiple entities may be separated and placed 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. Generally or additionally, multiple components (e.g., module or 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 they were performed by the corresponding component among the multiple components prior to integration.

[0044] 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.

[0045]

[0046] FIG. 1 is a block diagram showing a battery pack according to one embodiment disclosed in this document.

[0047] Referring to FIG. 1, a battery control system including a battery pack (1) and a higher controller (2) included in a higher system according to one embodiment disclosed in this document is schematically shown.

[0048] As illustrated in FIG. 1, the battery pack (1) may include a plurality of battery cells (11) (or one or more battery cells), a switching unit (14) connected in series to the first terminal side and / or second terminal side of the plurality of battery cells (11) to control the flow of charging and discharging current of the plurality of battery cells (11), and a battery management system (20) that monitors the voltage, current, temperature, etc. of the battery pack (1) to prevent overcharging and over-discharging.

[0049] In this case, the battery pack (1) may be equipped with a plurality of battery cells (11), a sensor (12), a switching unit (14), and / or a battery management system (20). For example, the first terminal may be the (+) terminal of the plurality of battery cells (11), and the second terminal may be the (-) terminal.

[0050] Here, the switching unit (14) is a device for controlling the current flow for charging or discharging a plurality of battery cells (11), and, for example, depending on the specifications of the battery pack (1), at least one relay, magnetic contactor, etc. may be used.

[0051] For example, a plurality of battery cells (11) may include a cylindrical battery. A cylindrical battery refers to a battery in which the battery material is packaged into a cylinder.

[0052] The battery management system (20) is an interface that receives values ​​of various parameters measured above, and may include a plurality of terminals and a circuit connected to these terminals to perform processing of the received values. Additionally, the battery management system (20) may control the ON / OFF of a switching unit (14), such as a relay or contactor, and may be connected to a battery cell (11) to monitor the status of each of the plurality of battery cells (11).

[0053] The upper controller (2) can transmit control signals for a plurality of battery cells (11) to the battery management system (20). Accordingly, the operation of the battery management system (20) can be controlled based on the signals applied from the upper controller (2).

[0054] According to an embodiment, the battery management system (20) may include the battery diagnostic device (100) of FIG. 2. According to another embodiment, the battery management system (20) may be a different system from the battery diagnostic device (100) of FIG. 2. That is, the battery diagnostic device (100) of FIG. 2 may be included in the battery pack (1) or may be composed of another device outside the battery pack (1). For convenience of explanation, the description is based on the premise that the battery diagnostic device (100) is composed of another device outside the battery pack (1).

[0055]

[0056] FIG. 2 is a block diagram showing the configuration of a battery diagnostic device according to one embodiment disclosed in this document.

[0057] A battery diagnostic device (100) according to one embodiment may include at least one of a processor (110), a memory (120), or an interface (130). The processor (110), the memory (120), and the interface (130) may be electrically and / or operably coupled with each other by an electronic component including a communication bus. Hereinafter, operably coupled hardware may mean that a direct connection or an indirect connection between the hardware is established via wired or wireless means so that a second hardware is controlled by a first hardware among the hardware. Although illustrated based on different blocks, the embodiment is not limited thereto, and some of the hardware of FIG. 2 (e.g., at least a portion of the processor (110), the memory (120), and the communication circuit (not shown)) may be included in a single integrated circuit such as a system on a chip (SoC). Communication methods between components may include buses, GPIO (general purpose input and output), SPI (serial peripheral interface), MIPI (mobile industry processor interface), etc.

[0058] A processor (110) of a battery diagnostic device (100) according to one embodiment may include a hardware component for processing data based on one or more instructions. The hardware component for processing data may include, for example, an arithmetic and logic unit (ALU), a floating point unit (FPU), a field programmable gate array (FPGA), a central processing unit (CPU), a microcontroller unit (MCU), and / or an application processor (AP). The number of processors (110) may be one or more. For example, the processor (110) may have the structure of a multi-core processor including a dual core, a quad core, a hexa core, or an octa core.

[0059] A memory (120) of a battery diagnostic device (100) according to one embodiment may include a hardware component for storing data and / or instructions that are input and / or output to a processor (110). The memory (120) may include, for example, volatile memory such as random-access memory (RAM) and / or non-volatile memory such as read-only memory (ROM). For example, the volatile memory may include at least one of dynamic RAM (DRAM), static RAM (SRAM), cache RAM, and pseudo SRAM (PSRAM). For example, the non-volatile memory may include at least one of programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), flash memory, hard disk, compact disk, and embedded multi-media card (eMMC). For example, the memory (120) may be configured to store a voltage profile representing a voltage change for a change in capacity of a battery cell comprising an electrode based on an LFP (lithium iron phosphate) material. For example, the LFP material may be included in the electrode (e.g., positive electrode) of the battery cell. For example, the battery cell may include a positive electrode comprising an LFP material and a negative electrode comprising a graphite material.

[0060] An interface (130) of a battery diagnostic device (100) according to one embodiment may be configured to generate various battery measurement values ​​from the battery. To this end, the interface (130) may include a measurement means such as a voltmeter, ammeter, and thermometer, and a communication circuit for establishing a communication link with an external device. As an example, the interface (130) may include a temperature sensor attached to a battery cell.

[0061] A battery diagnostic device (100) according to one embodiment can obtain a capacity profile representing the relationship between the capacity and voltage of a battery cell containing an LFP material using an interface (130). The capacity profile can be used in a non-destructive diagnostic method for diagnosing the condition of a battery cell without disassembling the battery cell. The capacity profile may represent the relationship between the capacity and voltage of a battery cell that changes while charging or discharging the battery cell. The capacity profile may vary depending on the charging rate or C-rate for charging the battery cell. For example, the capacity profile may include a differential capacity profile representing the change in capacity with respect to the change in voltage of the battery cell.

[0062] A battery diagnostic device (100) according to one embodiment can divide the entire voltage range included in the capacity profile into one or more voltage ranges.

[0063] For example, the battery diagnostic device (100) can distinguish one or more voltage ranges based on identifying the phase transition of the negative electrode. For example, the battery diagnostic device (100) can distinguish one or more voltage ranges based on a peak value indicating the phase transition of the negative electrode.

[0064] A battery diagnostic device (100) according to one embodiment can obtain a first differential capacity profile representing a change in the capacity of a battery cell with respect to a change in the voltage of a battery cell according to one or more voltage ranges.

[0065] For example, a battery diagnostic device (100) can obtain a first differential capacity profile representing the change in capacity of a battery cell with respect to the change in voltage of a battery cell based on interpolation.

[0066] For example, the battery diagnostic device (100) can obtain a change in capacity of a battery cell with respect to a change in voltage of a battery cell based on interpolation by using one or more voltage ranges included in a capacity profile. For example, interpolation may refer to a method for estimating a value located between two values ​​in a capacity profile. For example, the battery diagnostic device (100) can obtain a straight line containing two values ​​based on interpolation. The battery diagnostic device (100) can estimate a value located between two values ​​by obtaining a value included in the straight line based on interpolation.

[0067] For example, the battery diagnostic device (100) can identify two values ​​in each of one or more voltage ranges based on interpolation. For example, the battery diagnostic device (100) can obtain a different value between the two values ​​using the two values ​​identified in each of one or more voltage ranges. The battery diagnostic device (100) can obtain a first differential capacity profile by interpolating the capacity change according to the voltage change using interpolation.

[0068] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell based on a first differential capacity profile.

[0069] A battery diagnostic device (100) according to one embodiment can identify at least one peak in a first differential capacity profile.

[0070] For example, at least one peak may indicate a phase transition of the cathode.

[0071] A battery diagnostic device (100) according to one embodiment can identify a first voltage range including a voltage that exceeds a first voltage value corresponding to at least one peak among one or more voltage ranges.

[0072] For example, the first voltage range may be referred to as a high voltage region in terms of including a relatively high voltage in the first differential voltage profile. For example, the first voltage range may correspond to a specified SOC region (e.g., 80% or more).

[0073] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell based on a first voltage range.

[0074] A battery diagnostic device (100) according to one embodiment can acquire data related to a battery cell in the beginning of life (BoL) state. For example, the battery diagnostic device (100) can acquire a second differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell in the BoL state.

[0075] For example, the second differential capacitance profile can be obtained based on the charging rate and / or C-rate used to obtain the first differential capacitance profile.

[0076] In one embodiment, the battery diagnostic device (100) can identify a first characteristic section in which the slope of the second differential capacity profile changes within a first voltage range of the second differential capacity profile.

[0077] In one embodiment, the battery diagnostic device (100) can identify positive degradation of the battery cell depending on whether a second feature section corresponding to a first feature section in a first differential capacity profile is identified.

[0078] In one embodiment, a feature interval (e.g., a first feature interval or a second feature interval) may be identified according to the shape of a profile (e.g., a first derivative capacity profile or a second derivative capacity profile). For example, a feature interval may be identified when a change in the slope of the profile exceeding a specified slope range is obtained. For example, a feature interval may be identified when a value corresponding to the slope increases after decreasing. For example, a feature interval may include an inflection point of the profile. The shape of the profile included in the feature interval may have a form in which the slope of the gradient is relatively softened. However, it is not limited thereto.

[0079] In one embodiment, when the degradation of the LFP material included in the battery cell progresses, the amount of change in the slope of the profile may increase as the resistance within the battery cell increases. That is, the battery diagnostic device (100) can identify positive degradation of the battery cell based on the slope of the profile. For example, the battery diagnostic device (100) can identify positive degradation of the battery cell based on the slope of a first differential capacity profile included in a first voltage range.

[0080] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell exceeding a specified degree of degradation when a second feature section is not identified in a first differential capacity profile. A battery diagnostic device (100) according to one embodiment can identify a second voltage value included in the first feature section and a first differential capacity value corresponding to the second voltage value in a second differential capacity profile. A battery diagnostic device (100) according to one embodiment can identify a third voltage value corresponding to the second voltage value and a second differential capacity value corresponding to the third voltage value in a first differential capacity profile.

[0081] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell that exceeds a specified degradation level when the ratio of a first differential capacity value and a second differential capacity value exceeds a specified degradation level.

[0082] For example, the ratio of the first derivative value and the second derivative value may include the difference between the first derivative value and the second derivative value.

[0083] For example, the battery diagnostic device (100) can change the specified degree of degradation according to preset data. However, it is not limited thereto.

[0084] A battery diagnostic device (100) according to one embodiment may adjust the charging speed for charging a battery cell based on identifying positive degradation of a battery cell that exceeds a specified degradation level. For example, the battery diagnostic device (100) may lower the charging speed. For example, the battery diagnostic device (100) may adjust the charging upper voltage to lower the maximum voltage of the battery cell. However, it is not limited thereto.

[0085] A battery diagnostic device (100) according to one embodiment as described above can identify positive degeneration contained in a battery cell by using a differential capacity profile of a battery cell. For example, the battery diagnostic device (100) can identify positive degeneration of a battery cell based on a designated area (e.g., a first voltage range) of the differential capacity profile. For example, the battery diagnostic device (100) can identify positive degeneration of a battery cell by using a differential capacity profile and a change in slope due to positive degeneration. Based on identifying positive degeneration, the battery diagnostic device (100) can slow down the progression of positive degeneration by adjusting the charging speed of the battery cell.

[0086]

[0087] FIG. 3 illustrates an example of a graph showing data related to a battery cell obtained by a battery diagnostic device according to an embodiment disclosed in this document. The battery diagnostic device (100) of FIG. 3 may be referenced to the battery diagnostic device (100) of FIG. 2.

[0088] The graph (300) of FIG. 3 may include a first capacity profile (301) and a second capacity profile (302) representing the relationship between the capacity of the battery cell and the voltage of the battery cell.

[0089] For example, the first capacity profile (301) may include data related to a battery cell in the middle of life (MoL) state.

[0090] For example, the second capacity profile (302) may include data related to the battery cell in the BoL state.

[0091] For example, a battery cell in the MoL state may be included in a state where positive degradation has progressed relatively more than a battery cell in the BoL state.

[0092] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell by comparing a first capacity profile (301) and a second capacity profile (302).

[0093] For example, the battery diagnostic device (100) can identify a state of charge (SOC) region (305) that exceeds a specified state of charge (SOC) (303) (e.g., about 80%). The state of charge region (305) may correspond to a high potential region (e.g., a region exceeding 3.4V).

[0094] For example, the battery diagnostic device (100) can compare the slope of the first capacity profile (301) and the slope of the second capacity profile (302) in the SOC area (305).

[0095] For example, as positive degradation progresses, the internal resistance of the battery cell increases, so the capacity of the battery cell corresponding to the same voltage may decrease. In the SOC region (305), the slope of the first capacity profile (301) may be smaller than the slope of the second capacity profile (302).

[0096] For example, the battery diagnostic device (100) can diagnose positive degradation of a battery cell by using the slope (or voltage value) of the capacity profile included in a specific area (e.g., SOC area (305)). Hereinafter, with reference to FIG. 4, the operation of the battery diagnostic device (100) using a differential capacity profile to diagnose positive degradation of a battery cell will be described in more detail.

[0097]

[0098] FIG. 4 illustrates an example of a graph showing a differential capacity profile obtained by a battery diagnostic device according to an embodiment disclosed in this document. The battery diagnostic device (100) of FIG. 4 may be referenced to the battery diagnostic device (100) of FIG. 2. Referring to FIG. 4, the graph (400) may include a first differential capacity profile (401) showing a change in capacity of a battery cell with respect to a change in voltage of a battery cell in a MoL state, and a second differential capacity profile (402) showing a change in capacity of a battery cell with respect to a change in voltage of a battery cell in a BoL state.

[0099] Referring to FIG. 4, the size (e.g., differential capacity value) of the first differential capacity profile (401) according to one embodiment may be relatively smaller than the size of the second differential capacity profile (402). Since the battery cell in the MoL state has undergone more degradation relatively than the battery cell in the BoL state, the size (e.g., differential capacity value) of the first differential capacity profile (401) may be relatively smaller than the size of the second differential capacity profile (402). For example, the size (e.g., differential capacity value) of the differential capacity profile may be related to the degradation of the negative electrode of the battery cell.

[0100] A battery diagnostic device (100) according to one embodiment can divide the entire voltage range included in the first differential capacity profile (401) into one or more voltage ranges.

[0101] For example, the battery diagnostic device (100) can identify at least one peak (405) included in the first differential capacity profile (401). For example, the battery diagnostic device (100) can identify a first voltage range (407) that includes a voltage exceeding a first voltage value (406) corresponding to at least one peak (405) among one or more voltage ranges. For example, the first voltage range (407) may correspond to the SOC region (305) of FIG. 3.

[0102] For example, the battery diagnostic device (100) can identify at least one peak (405-1) included in the second differential capacity profile (402). For example, the battery diagnostic device (100) can identify a second voltage range including a voltage that exceeds a voltage value (e.g., a first voltage value (406)) corresponding to at least one peak (405-1) among one or more voltage ranges. For example, the second voltage range may correspond to the first voltage range (407).

[0103] A battery diagnostic device (100) according to one embodiment can identify a first characteristic section (409) in which the slope of the second differential capacity profile changes within a first voltage range (407) of the second differential capacity profile (402). For example, the battery diagnostic device (100) can identify positive degradation of a battery cell depending on whether a second characteristic section corresponding to the first characteristic section (409) is identified in the first differential capacity profile (401).

[0104] For example, the first feature interval (409) may represent a section of change in the slope of the profile that exceeds a specified slope range. For example, the first feature interval (409) may include an inflection point (e.g., a peak value (410)). However, it is not limited thereto. The first feature interval (409) may represent a feature in which the magnitude of the slope decreases and then increases.

[0105] For example, the second differential capacitance profile may include a section of slope change of the profile included in a slope range specified in the first voltage range (407). That is, the second differential capacitance profile (401) may not have a second feature section corresponding to the first feature section (409).

[0106] For example, the battery diagnostic device (100) can identify positive degradation of a battery cell exceeding a specified degree of degradation if the second feature interval is not identified in the first differential capacity profile (401).

[0107] For example, the battery diagnostic device (100) can identify positive degradation of the battery cell that is less than a specified degradation level when a second feature section is identified in the first differential capacity profile (401). That is, when the battery diagnostic device (100) identifies a second feature section corresponding to the first feature section (409), it may not initiate processing of an operation to mitigate positive degradation of the battery cell.

[0108] A battery diagnostic device (100) according to one embodiment can identify a second voltage value (408) included in a first feature section (409) in a second differential capacity profile (402) and a first differential capacity value (410-1) corresponding to the second voltage value (408).

[0109] A battery diagnostic device (100) according to one embodiment can identify a third voltage value corresponding to a second voltage value (408) included in a first feature interval (409). The third voltage value may be included in the second voltage value (408). For example, the battery diagnostic device (100) can identify the third voltage value and a second differential capacity value (411-1) corresponding to the third voltage value.

[0110] For example, the battery diagnostic device (100) can identify at least one point (411) corresponding to a second voltage value (408) in a first differential capacity profile (401). Based on identifying the profile value (411), the battery diagnostic device (100) can identify a second differential capacity value (411-1).

[0111] A battery diagnostic device (100) according to one embodiment can identify positive degradation of a battery cell when the ratio of a first differential capacity value (410-1) and a second differential capacity value (411-1) exceeds a specified degree of degradation. For example, the battery diagnostic device (100) can identify positive degradation of a battery cell by using the difference between the first differential capacity value (411-1) and the second differential capacity value (410-1).

[0112] For example, if the battery diagnostic device (100) identifies positive degradation of a battery cell exceeding a specified degradation level, it may adjust the charging speed for charging the battery cell. However, it is not limited thereto.

[0113] Referring to FIG. 4, although a differential capacity profile related to the charging of a battery cell has been described, it is obvious that the battery diagnostic device (100) can diagnose positive degradation of the battery cell using a differential capacity profile related to the discharging of the battery cell.

[0114] A battery diagnostic device (100) according to an embodiment as described above can diagnose positive degradation of a battery cell by using a differential capacity value corresponding to a specified voltage value (e.g., a second voltage value (408)). By diagnosing positive degradation of a battery cell using a differential capacity profile, the battery diagnostic device (100) can mitigate non-uniformity within the battery cell. When a battery cell degrades, it may have a region (e.g., a negative electrode) where particles within the battery cell react relatively more. The battery diagnostic device (100) can slow down the degradation of the battery cell by adjusting the charging speed to mitigate non-uniformity within the battery cell.

[0115]

[0116] FIG. 5 illustrates an example of a graph showing a differential capacity profile according to the discharge of a battery cell according to an embodiment disclosed in this document. The battery diagnostic device (100) of FIG. 5 may be referenced to the battery diagnostic device (100) of FIG. 2. Referring to FIG. 5, the graph (500) may include a first differential capacity profile (501) and a second differential capacity profile (502) obtained while discharging the battery cell.

[0117] For example, the first differential capacity profile (501) may represent the change in capacity with respect to the change in voltage of the battery cell in the MoL state. The second differential capacity profile (502) may represent the change in capacity with respect to the change in voltage of the battery cell in the BoL state.

[0118] A battery diagnostic device (100) according to one embodiment can identify a voltage value (505) related to the degradation of the positive electrode among the positive and negative electrodes of a battery cell through pre-specified data.

[0119] For example, the battery diagnostic device (100) can identify a first differential capacity value (507) corresponding to a voltage value (505) in a first differential capacity profile (501).

[0120] For example, the battery diagnostic device (100) can identify a second differential capacity value (506) corresponding to a voltage value (505) in a second differential capacity profile (502).

[0121] A battery diagnostic device (100) according to one embodiment can diagnose positive degradation of a battery cell based on the ratio of a first differential capacity value (507) and a second differential capacity value (506).

[0122] For example, if the above ratio exceeds a specified degree of degradation, the battery diagnostic device (100) can identify positive degradation of the battery cell. For example, the battery diagnostic device (100) can adjust the charging speed for charging the battery cell based on the identification of positive degradation of the battery cell.

[0123]

[0124] FIG. 6 illustrates an example of a flowchart showing operations performed by a battery diagnostic device according to an embodiment disclosed in this document. Hereinafter, it is assumed that the battery diagnostic device (100) of FIG. 2 performs the process of FIG. 6. Furthermore, the operations described as being performed by the device can be understood as being controlled by the processor (110) of the battery diagnostic device (100). Each of the operations of FIG. 6 may be performed sequentially, but is not necessarily performed sequentially. For example, the order of each of the operations may be changed, and at least two operations may be performed in parallel. In addition, the operation of the battery diagnostic device (100) may be performed by a Battery Management System (BMS) in a vehicle, as well as by various devices such as a server, cloud, charger, or charge / discharger.

[0125] In operation S610, a battery diagnostic device according to one embodiment can obtain a first differential capacity profile (e.g., the first differential capacity profile (401) of FIG. 4) representing a change in the capacity of a battery cell with respect to a change in the voltage of the battery cell.

[0126] In operation S620, the battery diagnostic device according to one embodiment can divide the entire voltage range included in the first differential capacity profile into one or more voltage ranges.

[0127] For example, the battery diagnostic device (100) can identify a first voltage range (e.g., a first voltage range (407) of FIG. 4) that includes a voltage value (e.g., a first voltage value (406)) that exceeds a voltage value corresponding to at least one peak (e.g., at least one peak (405) of FIG. 4) among one or more voltage ranges.

[0128] In operation S630, a battery diagnostic device according to one embodiment can identify positive degradation of a battery cell based on a first voltage range among one or more voltage ranges.

[0129] For example, a battery diagnostic device can identify positive degradation of a battery cell based on the slope of a first differential capacity profile in a first voltage range.

[0130] For example, if a battery diagnostic device identifies positive degradation of a battery cell that exceeds a specified degradation level, it can reduce the charging speed for charging the battery cell.

[0131] For example, if the battery diagnostic device identifies positive degradation of a battery cell exceeding a specified degradation level, it can limit the top charging voltage of the battery cell.

[0132]

[0133] FIG. 7 shows a computing system that executes a battery diagnostic method according to one embodiment disclosed in this document.

[0134] Referring to FIG. 7, a computing system (1000) according to one embodiment disclosed in this document may include an MCU (1010), a memory (1020), an input / output I / F (1030), and a communication I / F (1040).

[0135] The MCU (1010) may be a processor that executes various programs stored in memory (1020) (e.g., SOH calculation program, cell balancing target determination program, etc.), processes various data including SOC (state of charge), SOH (state of health), etc. of multiple battery cells through these programs, and performs the functions of the battery diagnostic device (100) described above. The MCU (1010) may be a BMS, a separate PC, or a cloud, but is not limited thereto.

[0136] The memory (1020) can store various programs regarding the calculation of the battery cell's SOH and the determination of the target for cell balancing. Additionally, the memory (1020) can store various data such as SOC data and SOH data for each battery cell.

[0137] These memories (1020) may be provided in multiple quantities as needed. The memories (1020) may be volatile memories or non-volatile memories. As volatile memories, the memory (1020) may use RAM, DRAM, SRAM, etc. As non-volatile memories, the memory (1020) may use ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc. The examples of the memories (1020) listed above are merely examples and are not limited to these examples.

[0138] The input / output I / F (1030) can provide an interface that enables data transmission and reception between an input device (not shown), such as a keyboard, mouse, or touch panel, an output device (not shown), and an MCU (1010).

[0139] The communication I / F (1040) is configured to transmit and receive various data to and from a server and may be various devices capable of supporting wired or wireless communication. For example, through the communication I / F (1040), programs for calculating the SOH of a battery cell or determining a balancing target, or various data, can be transmitted and received from an external server provided separately.

[0140] As such, a battery diagnostic method according to one embodiment disclosed in this document can be recorded in memory (1020) and executed by an MCU (1010).

[0141] As described above, even though all components constituting the embodiments disclosed in this document have been described as being combined or operating in combination, the embodiments disclosed in this document are not necessarily limited to such embodiments. That is, within the scope of the purposes of the embodiments disclosed in this document, all components may be selectively combined in one or more ways to operate.

[0142] Furthermore, terms such as "include," "compose," or "have" as described above, unless specifically stated otherwise, mean that the relevant component may be inherent; thus, they should be interpreted as allowing for the inclusion of additional components rather than excluding them. All terms, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as those defined in advance, should be interpreted in accordance with their contextual meanings in the relevant technology and, unless explicitly defined in this document, should not be interpreted in an ideal or overly formal sense.

[0143] The above description is merely an illustrative explanation of the technical concept disclosed in this document, and a person skilled in the art to which the embodiments disclosed in this document belong may make various modifications and variations within the scope of the essential characteristics of the embodiments disclosed in this document. Accordingly, the embodiments disclosed in this document are intended to explain, not limit, the technical concept of the embodiments disclosed in this document, and the scope of the technical concept disclosed in this document is not limited by these embodiments. The scope of protection of the technical concept disclosed in this document shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this document.

Claims

1. An interface for obtaining a capacity profile representing a voltage for the capacity of a battery cell including an electrode based on LFP (lithium iron phosphate) material; and It includes at least one processor, The above-mentioned at least one processor is, A first differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell is obtained, and The entire voltage range included in the first differential capacitance profile is divided into one or more voltage ranges, and Configured to identify positive electrode degradation of the battery cell based on a first voltage range among the one or more voltage ranges mentioned above, Battery diagnostic device.

2. In Paragraph 1, The above-mentioned at least one processor is, Identify at least one peak included in the first differential capacity profile above, and Identifying the first voltage range including a voltage exceeding the first voltage value corresponding to at least one peak among the above one or more voltage ranges, and Configured to identify positive degradation of the battery cell based on the above first voltage range, Battery diagnostic device.

3. In Paragraph 2, The above-mentioned at least one processor is, A second differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell in the BoL (beginning of life) state is obtained, and In the first voltage range of the second differential capacitance profile, a first characteristic section in which the slope of the second differential capacitance profile changes is identified, and A configuration for identifying positive degradation of the battery cell based on whether a second feature section corresponding to the first feature section is identified in the first differential capacity profile. Battery diagnostic device.

4. In Paragraph 3, The above-mentioned at least one processor is, If the second feature interval is not identified in the first differential capacity profile, configured to identify positive degradation of the battery cell exceeding a specified degradation degree, Battery diagnostic device.

5. In Paragraph 4, The above-mentioned at least one processor is, Identifying a second voltage value included in the first feature interval and a first differential capacitance value corresponding to the second voltage value in the second differential capacitance file, and Identifying a third voltage value corresponding to the second voltage value and a second differential capacitance value corresponding to the third voltage value in the first differential capacitance file, and If the ratio of the first derivative capacity value and the second derivative capacity value exceeds the specified degradation degree, the positive degradation of the battery cell exceeding the specified degradation degree is identified, and Based on identifying positive degradation of the battery cell exceeding the specified degradation level, configured to adjust the charging speed for charging the battery cell, Battery diagnostic device.

6. In Paragraph 3, The above-mentioned at least one processor is, When the second feature interval is identified in the first differential capacity profile, configured to identify positive degradation of the battery cell below the specified degradation degree, Battery diagnostic device.

7. In Paragraph 2, The above-mentioned at least one processor is, A configuration for identifying positive degradation of the battery cell based on the slope of the first differential capacity profile included in the first voltage range, Battery diagnostic device.

8. In Paragraph 2, The above at least one peak is, Indicating the phase transition of the negative electrode of the above battery cell, Battery diagnostic device.

9. In Paragraph 1, The above-mentioned at least one processor is, Based on interpolation, configured to obtain the first differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell according to the one or more voltage ranges. Battery diagnostic device.

10. The operation of obtaining a first differential capacity profile representing the change in capacity of a battery cell with respect to a change in voltage of a battery cell including an electrode based on LFP (lithium iron phosphate) material, An operation of dividing the entire voltage range included in the first differential capacitance profile into one or more voltage ranges, and The operation of identifying positive electrode degradation of the battery cell based on a first voltage range among the one or more voltage ranges mentioned above, Battery diagnostic method.

11. In Paragraph 10, The operation of identifying positive degradation of the above battery cell is, The operation of identifying at least one peak included in the first differential capacity profile, An operation of identifying a first voltage range including a voltage exceeding a first voltage value corresponding to at least one peak among the above one or more voltage ranges, and A method including an operation to identify positive degradation of the battery cell based on the first voltage range above. Battery diagnostic method.

12. In Paragraph 11, The operation of identifying positive degradation of the above battery cell is, The operation of obtaining a second differential capacity profile representing the change in capacity of the battery cell with respect to the change in voltage of the battery cell in the BoL (beginning of life) state, An operation to identify a first feature interval in which the slope of the second differential capacitance profile changes within the first voltage range of the second differential capacitance profile, and The operation of identifying positive degradation of the battery cell based on whether a second feature section corresponding to the first feature section is identified in the first differential capacity profile is included. Battery diagnostic method.

13. In Paragraph 12, The operation of identifying positive degradation of the above battery cell is, If the second feature interval is not identified in the first differential capacity profile, the operation further includes identifying positive degradation of the battery cell exceeding a specified degradation degree. Battery diagnostic method.

14. In Paragraph 13, The operation of identifying positive degradation of the battery cell exceeding the aforementioned specified degradation degree is, The operation of identifying a second voltage value included in the first feature interval and a first differential capacity value corresponding to the second voltage value in the second differential capacity file, The operation of identifying a third voltage value corresponding to the second voltage value and a second differential capacitance value corresponding to the third voltage value in the first differential capacitance file, When the ratio of the first differential capacity value and the second differential capacity value exceeds the specified degradation degree, an operation to identify positive degradation of the battery cell exceeding the specified degradation degree, and Based on identifying positive degradation of the battery cell exceeding the specified degradation degree, the method further includes the operation of adjusting the charging speed for charging the battery cell. Battery diagnostic method.

15. In Paragraph 12, The operation of identifying positive degradation of the above battery cell is, If the second feature interval is identified in the first differential capacity profile, the operation further includes identifying positive degradation of the battery cell below the specified degradation degree. Battery diagnostic method.

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