Apparatus and method for diagnosing battery

Abstract

A battery diagnosis device according to one embodiment of the present disclosure includes: a curve acquisition unit that acquires a battery curve indicating a correspondence relationship between a voltage and a capacity of a battery; and a control unit that divides a capacity section of the battery curve into a plurality of sections, derives, from each of the divided sections, a target value of one target index relating to a differential capacity peak or resistance among a plurality of preset diagnostic indexes, the derived correspondence relationship between the plurality of target values is compared with a preset reference curve representing a correspondence relationship between the plurality of target indicators, and the state of the battery is diagnosed based on a result of the comparison.

Description

Technical Field

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2024-0015281, filed with the Korean Intellectual Property Office on January 31, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to battery diagnostic apparatus and methods, and more particularly to battery diagnostic apparatus and methods for diagnosing the state of a battery. Background Technology

[0003] Recently, with the rapid increase in demand for portable electronic products such as laptops, cameras and mobile phones, and with the vigorous development of electric vehicles, energy storage batteries, robots and satellites, research is actively underway on high-performance batteries that allow for repeated charging and discharging.

[0004] Currently, commercially available batteries include, for example, nickel-cadmium (NiCd) batteries, nickel-metal hydride (NiMH) batteries, nickel-zinc (NiZn) batteries, and lithium-ion (Li-ion) batteries. Among these, lithium-ion batteries have gained considerable attention due to their advantages, including a significantly lower memory effect compared to nickel-based batteries, allowing for greater freedom in charging and discharging, a very low self-discharge rate, and high energy density.

[0005] While much research is focused on high-capacity and high-density batteries, improving battery life and safety is also crucial. To enhance battery safety, a technology capable of accurately diagnosing the current state of a battery is needed. Summary of the Invention

[0006] Technical issues

[0007] This disclosure provides a battery diagnostic apparatus and method that can diagnose the state of a battery and control the battery based on the diagnostic results.

[0008] Various aspects of this disclosure will be understood from the following description and will become more apparent from the embodiments thereof. Furthermore, it will be readily understood that various aspects of this disclosure can be implemented by the apparatus and combinations thereof as described in the claims.

[0009] Technical solution

[0010] A battery diagnostic apparatus according to one aspect of this disclosure may include: a curve acquisition unit that acquires a battery curve representing the correspondence between the battery's voltage and capacity; and a control unit that divides the capacity segment of the battery curve into multiple segments, derives a target value of a target indicator related to the differential capacity peak or resistance from each of a plurality of pre-set diagnostic indicators in each segment, compares the correspondence between the derived multiple target values ​​with a preset reference curve representing the correspondence between the multiple target indicators, and diagnoses the battery's state based on the comparison result.

[0011] The control unit can be configured to determine the number of differential capacity peaks, the area of ​​the differential curve, the voltage of the main peak, or the differential capacity of the main peak among the multiple differential capacity peaks, as target indicators corresponding to the low-capacity segment among multiple segments in the differential curve that corresponds to the battery curve and represents the relationship between voltage and differential capacity.

[0012] The control unit can be configured to determine the resistance as a target value corresponding to the high-capacity segment among multiple segments.

[0013] The control unit can be configured to diagnose the battery state as a deterioration state of the positive and negative electrodes when the target point indicating the correspondence between multiple target values ​​is included in the reference curve.

[0014] The control unit can be configured to diagnose the battery state as negative electrode deterioration when the target point is included in the first region based on the reference curve.

[0015] The control unit can be configured to diagnose the battery state as positive electrode deterioration when the target point is included in the second region based on the reference curve.

[0016] The control unit can be configured to diagnose the battery's state as end-of-life (EOL) when the target point is included in the third region.

[0017] The third region is configured to be a region that exceeds a preset threshold for each of the multiple target metrics.

[0018] The control unit can be configured to reduce the battery's current rate to at least one of a set upper limit current rate (C rate) and a constant voltage charging time when the battery's state is diagnosed as either a positive electrode deterioration state or a positive or negative electrode deterioration state.

[0019] The control unit can be configured to reduce the battery's charging upper limit voltage to the battery's set value when the battery's state is diagnosed as negative electrode deterioration or positive and negative electrode deterioration.

[0020] The control unit can be configured to divide the capacity segment into a first segment and a second segment based on a preset division ratio or target capacity.

[0021] The curve acquisition unit can be configured to further acquire the differential curve corresponding to the battery curve.

[0022] The control unit can be configured to determine the main peak based on the differential curve and to divide the capacity segments based on the capacity of the determined main peak.

[0023] The differential curve can be configured to represent the relationship between the battery's capacity and its differential voltage.

[0024] The control unit can be configured to identify multiple local minimum points in the differential curve, and to identify the local minimum point with the smallest corresponding differential voltage among the identified multiple local minimum points as the main peak.

[0025] The differential curve can be configured to represent the relationship between the battery's voltage and its differential capacity.

[0026] The control unit can be configured to determine multiple local maximum points in the differential curve, and to determine the local maximum point with the largest corresponding differential voltage among the determined multiple local maximum points as the main peak.

[0027] A battery pack according to another aspect of this disclosure may include a battery diagnostic device according to an embodiment of this disclosure.

[0028] A vehicle according to another aspect of this disclosure may include a battery diagnostic device according to an embodiment of this disclosure.

[0029] A battery diagnostic method according to another aspect of this disclosure may include: a curve acquisition step, which acquires a battery curve representing the correspondence between the battery's voltage and capacity; a segmentation step, which divides the capacity segment of the battery curve into multiple segments; a target value derivation step, which derives a target value from each of a plurality of pre-defined diagnostic indicators related to the differential capacity peak or resistance from each segment; a comparison step, which compares the correspondence between the derived plurality of target values ​​with a pre-defined reference curve representing the correspondence between the plurality of target indicators; and a diagnostic step, which diagnoses the state of the battery based on the comparison results.

[0030] According to another aspect of this disclosure, a non-transitory computer-readable storage medium may store a program therein that, when executed, causes a computer to perform a battery diagnostic method, the battery diagnostic method comprising: a curve acquisition step, which acquires a battery curve representing the correspondence between the battery's voltage and capacity; a segmentation step, which divides the capacity segment of the battery curve into multiple segments; a target value derivation step, which derives a target value from each of a plurality of pre-defined diagnostic indicators related to the differential capacity peak or resistance from each of the segmented segments; a comparison step, which compares the correspondence between the derived plurality of target values ​​with a preset reference curve representing the correspondence between the plurality of target indicators; and a diagnostic step, which diagnoses the state of the battery based on the comparison results.

[0031] Beneficial effects

[0032] According to one aspect of this disclosure, a battery diagnostic apparatus can diagnose the state of a battery in various aspects based on a combination of various target indicators.

[0033] Since the target value for each segment is a value that indicates the state of the battery corresponding to the corresponding segment, the state of the battery can be separated and diagnosed in more detail based on the correspondence between multiple target values.

[0034] The effects of this disclosure are not limited to those mentioned above, and those skilled in the art will clearly understand other effects not mentioned in the description of the claims. Attached Figure Description

[0035] The accompanying drawings illustrate embodiments of the present disclosure and, together with the detailed description of the disclosure to be described later, are used to further understand the technical concept of the disclosure. Therefore, this disclosure should not be construed as limited to the contents illustrated in the drawings.

[0036] Figure 1 This is a schematic diagram of a battery diagnostic apparatus according to an embodiment of the present disclosure.

[0037] Figure 2 This is a schematic diagram illustrating a battery curve according to an embodiment of the present disclosure.

[0038] Figure 3 This is a schematic diagram illustrating multiple target metrics according to an embodiment of the present disclosure.

[0039] Figure 4 This is a schematic diagram illustrating a reference curve according to an embodiment of the present disclosure.

[0040] Figure 5 This is a schematic diagram illustrating a differential curve according to an embodiment of the present disclosure.

[0041] Figure 6 This is a schematic diagram of a battery pack according to another embodiment of the present disclosure.

[0042] Figure 7 This is a schematic diagram of a vehicle according to yet another embodiment of the present disclosure.

[0043] Figure 8 This is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present disclosure. Detailed Implementation

[0044] The words and terms used in the detailed description and claims herein should not be construed as limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical ideas of the present disclosure, in accordance with the principle that the inventors may appropriately define terms and concepts for the purposes of best describing the present disclosure.

[0045] Therefore, it is understood that the embodiments described herein and the configurations illustrated in the accompanying drawings are merely examples of this disclosure and do not represent the technical ideas of this disclosure in detail. Various equivalents and modifications can be made to replace this disclosure when it is submitted.

[0046] When describing this disclosure, if a detailed description of a relevant known configuration or function is determined to obscure the gist of this disclosure, such detailed description may be omitted.

[0047] Terms with ordinal numbers such as first, second, etc., can be used to distinguish one part from another among various parts, but should not be interpreted as limiting parts.

[0048] Throughout this description, unless otherwise defined, when a section “includes” a particular component, the description does not indicate that the section excludes other components, but rather that the section may also include other components.

[0049] Furthermore, throughout this description, when two components are “connected” to each other, the description indicates not only that the two components are “directly connected” to each other, but also that the two components are “indirectly connected” to each other via another component.

[0050] Embodiments of this disclosure are described in detail below with reference to the accompanying drawings.

[0051] Figure 1 This is a schematic diagram illustrating a battery diagnostic device 100 according to an embodiment of the present disclosure.

[0052] refer to Figure 1 The battery diagnostic device 100 may include a curve acquisition unit 110, a control unit 120, and a storage unit 130.

[0053] Here, a battery refers to a physically separable, single, isolated cell with a negative and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery can be considered a battery. The type of battery can be cylindrical, prismatic, or pouch-shaped. Furthermore, a battery can represent a battery bank, battery module, or battery pack in which multiple cells are connected in series and / or parallel. In the following description, for ease of description, it will be assumed that a battery refers to a single, isolated cell.

[0054] The curve acquisition unit 110 can be configured to acquire a battery curve BP that indicates the relationship between the battery's voltage and capacity.

[0055] For example, the battery curve BP represents the relationship between voltage V and capacity Q as the battery's capacity increases from a preset initial charging capacity or 0% to a preset final charging capacity or 100%. In another example, the battery curve BP could represent the relationship between voltage V and capacity Q as the battery's capacity increases from a preset initial discharging capacity or 100% to a preset final discharging capacity or 0%.

[0056] For example, there are no particular restrictions on the current rate (C rate) used to generate the battery curve BP during charging or discharging. However, to obtain a more accurate battery curve BP and differential curve, the battery should be charged or discharged at a low rate. For example, the battery curve BP can be generated during charging or discharging of the battery at 0.05 C.

[0057] The curve acquisition unit 110 can acquire the battery curve BP in the following manner.

[0058] For example, the curve acquisition unit 110 can directly read or receive the battery curve BP from an external source. For example, the curve acquisition unit 110 can acquire the battery curve BP by connecting to an external source via a wired and / or wireless connection and reading or receiving the battery curve BP.

[0059] In another example, curve acquisition unit 110 can directly generate battery curve BP based on battery information regarding the battery's voltage and capacity. For instance, curve acquisition unit 110 can acquire battery curve BP by directly generating battery curve BP based on battery information.

[0060] Figure 2 This is a schematic diagram illustrating a battery curve BP according to an embodiment of the present disclosure. Figure 2 In one embodiment, the battery curve BP can be expressed as an XY curve, where the X-axis is set to capacity Q and the Y-axis is set to voltage V.

[0061] The curve acquisition unit 110 can be communicatively connected to the control unit 120. For example, the curve acquisition unit 110 can be wired or wirelessly connected to the control unit 120. In one example, the curve acquisition unit 110 can send the acquired battery curve BP to the control unit 120. In another example, the control unit 120 can read the battery curve BP from the curve acquisition unit 110.

[0062] According to one embodiment, the control unit 120 can be configured to divide the capacity segment of the battery curve BP into multiple segments.

[0063] For example, the control unit 120 can divide the entire capacity range of the battery curve BP into two or more segments. For example, in Figure 2 In this embodiment, the entire capacity range of the battery curve BP is Qi to Qf. The control unit 120 can divide the capacity range of Qi to Qf into a first segment R1 and a second segment R2 based on Qk.

[0064] The control unit 120 can be configured to export a target value of a target indicator related to differential capacitance peak or resistance among a plurality of preset diagnostic indicators in each segment.

[0065] For example, multiple diagnostic indicators can be preset for each of the multiple segments. Here, a diagnostic indicator is an indicator that represents the state of the battery in the corresponding segment and can be used to diagnose the state of the battery in the corresponding segment. For example, since there are special indicators that can only be derived from each of the multiple segments, some or all of the diagnostic indicators set for each of the multiple segments can be different.

[0066] Figure 3 This is a schematic diagram illustrating multiple target metrics according to an embodiment of the present disclosure.

[0067] (1) The number of differential voltage peaks is the number of peaks included in the corresponding segment of the first differential curve. For example, the number of local maximum points and / or local minimum points included in the corresponding segment of the first differential curve can be determined as the number of differential voltage peaks.

[0068] A differential voltage peak refers to a peak included in the first differential curve, which is the result of differentiating the battery curve BP with respect to capacity. For example, when differentiating the battery curve BP with respect to capacity, a first differential curve can be derived, indicating the correspondence between capacity Q and differential voltage dV / dQ. Furthermore, the first differential curve may include multiple differential voltage peaks. Here, a differential voltage peak refers to a local maximum point and / or a local minimum point included in the first differential curve.

[0069] (2) The capacity of the differential voltage peak is the capacity of the target peak included in the corresponding segment of the first differential curve. For example, among one or more local maximum points included in the corresponding segment of the first differential curve, the peak with the largest corresponding differential voltage can be identified as the target peak. The target peak can be changed according to the state of the battery to be diagnosed.

[0070] (3) The differential voltage of the differential voltage peak is the differential voltage of the target peak included in the corresponding segment of the first differential curve.

[0071] (4) The differential voltage area is the area of ​​the corresponding segment of the first differential curve. The integral value of the capacity in the corresponding segment of the first differential curve can be determined as the differential voltage area.

[0072] (5) The number of differential capacity peaks is the number of peaks included in the corresponding segment of the second differential curve. For example, the number of local maximum points and / or local minimum points included in the corresponding segment of the second differential curve can be determined as the number of differential voltage peaks.

[0073] Here, the differential capacity peak refers to the peak included in the second differential curve, which is the result of differentiating the battery curve BP with respect to voltage. For example, when the battery curve BP is differentiated with respect to voltage, a second differential curve can be derived, indicating the correspondence between voltage V and differential capacity dQ / dV. Furthermore, the first differential curve may include multiple differential capacity peaks. Here, the differential capacity peak refers to a local maximum point and / or a local minimum point included in the second differential curve.

[0074] (6) The voltage of the differential capacity peak is the voltage of the target peak included in the corresponding segment of the second differential curve. For example, among one or more local maximum points included in the corresponding segment of the second differential curve, the peak with the largest corresponding differential capacity can be identified as the target peak. The target peak can be changed according to the state of the battery to be diagnosed.

[0075] (7) The differential capacity of the differential capacity peak is the differential capacity of the target peak included in the corresponding segment of the second differential curve.

[0076] (8) The differential capacity area is the area of ​​the corresponding segment of the second differential curve. The integral value of the voltage in the corresponding segment of the second differential curve can be determined as the differential capacity area.

[0077] (9) The discharge end voltage refers to the open circuit voltage (OCV) after the battery has finished discharging. Since the discharge end voltage can be derived at the end of the battery's discharge, it is a diagnostic indicator that can only be derived in the low-capacity range. For example, the discharge end voltage can be derived in the low-capacity range corresponding to the voltage set to end the battery's discharge.

[0078] (10) The end-of-charge voltage refers to the OCV after the battery has finished charging. Since the end-of-charge voltage can be derived at the end of the battery's charging process, it is a diagnostic indicator that can only be derived in the high-capacity segment. For example, the end-of-charge voltage can be derived in the high-capacity segment corresponding to the voltage set to end the battery's charging process.

[0079] (11) Section resistance refers to the ratio of the voltage change in the corresponding section to the charging / discharging current.

[0080] (12) Charging efficiency refers to the difference between charging capacity and discharging capacity. For example, the charging efficiency of the low-capacity segment in the nth cycle can be calculated using the formula "charging capacity of the nth cycle - discharging capacity of the nth cycle". Furthermore, the charging efficiency of the high-capacity segment in the nth cycle can be calculated using the formula "discharging capacity of the nth cycle - charging capacity of the (n+1)th cycle". For example, charging efficiency is not limited to a specific segment but can be calculated based on the total charging / discharging capacity of the cycle.

[0081] (13) Segment capacity refers to the capacity of a segment.

[0082] (14) The CC charge capacity ratio is the ratio of the constant current (CC) charge capacity to the sum of the CC charge capacity and the constant voltage (CV) charge capacity. Since CV charging is performed at the end of charging, the CC charge capacity ratio is a diagnostic metric that can be derived only in the high-capacity segment. For example, the CC charge capacity ratio can be derived in the high-capacity segment corresponding to the voltage set to end the charging of the battery.

[0083] In one embodiment, the control unit 120 may identify a diagnostic indicator related to differential capacitance peaks or resistance from among the multiple diagnostic indicators described above for each of the multiple segments.

[0084] For example, the control unit 120 can be configured to determine the number of multiple differential capacity peaks included in the differential curve, the area of ​​the differential curve, the voltage of the main peak among the multiple differential capacity peaks, or the differential capacity of the main peak as a target indicator corresponding to the low capacity segment among multiple segments. The differential curve represents the correspondence between voltage and differential capacity and serves as the differential curve corresponding to the battery curve.

[0085] Therefore, in Figure 3 In one embodiment, the control unit 120 can determine one of the following as the target index for the low-capacity segment: the number of differential capacity peaks, the voltage of the differential capacity peaks, the differential capacity of the differential capacity peaks, and the differential capacity area.

[0086] Furthermore, the control unit 120 can be configured to determine the resistance as a target indicator corresponding to the high-capacity segment among multiple segments.

[0087] In this way, Figure 3 In one embodiment, the control unit 120 can determine the section resistance as a target indicator for the high-capacity section.

[0088] The control unit 120 can be configured to compare the correspondence between the derived multiple target values ​​with a reference curve that is preset to indicate the correspondence between the multiple target indicators.

[0089] According to one embodiment, assuming the capacity segment of the battery curve BP is divided into a first segment R1 and a second segment R2, a first target value of the target index is derived in the first segment R1, and a second target value of the target index is derived in the second segment R2. The control unit 120 can compare the target points indicating the correspondence between multiple target values ​​with a reference curve.

[0090] Figure 4 This is a schematic diagram illustrating a reference curve according to an embodiment of the present disclosure. Figure 4 In one embodiment, the reference curve can be represented as an XY curve, where the X-axis is set as a second target value and the Y-axis is set as a first target value.

[0091] For example, control unit 120 can determine whether the target point is included in the reference curve. When the target point is not included in the reference curve, control unit 120 can determine which of the first region T1, the second region T2, and the third region T3 the target point is included in.

[0092] The first region T1 is the region where the first target value is greater than the reference curve. For example, in... Figure 4 In one embodiment, the first region T1 is a region in which the first target value of the target point exceeds the first target value of the reference curve, based on the same second target value.

[0093] The second region T2 is the region where the second target value is greater than the reference curve. For example, in... Figure 4 In one embodiment, the second region T2 is a region in which the second target value of the target point exceeds the second target value of the reference curve, based on the same first target value.

[0094] The third region T3 can be configured to be a region that exceeds a preset threshold for each of a plurality of target metrics. The threshold can be set independently for each of the first and second target values. For example, in Figure 4In one embodiment, the third region T3 is the region where the first target value of the target point exceeds the first threshold th1 and the second target value of the target point exceeds the second threshold th2.

[0095] exist Figure 4 In some embodiments, the target point may be included in a reference curve, a first region T1, a second region T2, or a third region T3.

[0096] The control unit 120 can be configured to diagnose the state of the battery based on the comparison results.

[0097] For example, the control unit 120 can be configured to diagnose the battery state as a positive and negative electrode deterioration state when a target point indicating the correspondence between multiple target values ​​is included in a reference curve. A positive and negative electrode deterioration state is a state in which both the positive and negative electrodes of the battery are deteriorated, and the degree of deterioration is balanced between the positive and negative electrodes.

[0098] In another example, the control unit 120 can be configured to diagnose the battery state as a negative electrode degradation state when the target point is included in a first region T1 based on a reference curve. Here, a negative electrode degradation state is a state in which the degradation of the negative electrode of the battery is more dominant than that of the positive electrode. For example, a negative electrode degradation state is a state in which the degradation of the positive and negative electrodes is unbalanced and the degradation of the negative electrode is more severe than that of the positive electrode. For example, a negative electrode degradation state is associated with the loss of available lithium. When available lithium is lost, lithium metal deposition (Li plating) may occur on the surface of the negative electrode.

[0099] In another example, the control unit 120 can be configured to diagnose the battery state as a positive electrode degradation state when the target point is included in a second region T2 based on a reference curve. Here, a positive electrode degradation state is a state in which the positive electrode of the battery is degraded and the degradation of the positive electrode is more dominant than that of the negative electrode. For example, a positive electrode degradation state is a state in which the degradation of the positive and negative electrodes is unbalanced and the degradation of the positive electrode is more severe than that of the negative electrode.

[0100] In another example, control unit 120 can be configured to diagnose the battery's state as end-of-life (EOL) when the target point is included in the third region T3. EOL state refers to a state where the battery has significantly deteriorated and is not recommended for use. For example, EOL state could be a state where the battery can be determined to be unusable.

[0101] According to one embodiment of the present disclosure, a battery diagnostic apparatus 100 can diagnose the state of a battery based on the correspondence between target values ​​calculated in each of a plurality of segments. For example, according to one embodiment of the present disclosure, the state of a battery can be diagnosed in various aspects based on a combination of various target indicators.

[0102] Since the target value for each segment is a value that indicates the state of the battery corresponding to the corresponding segment, the state of the battery can be separated and diagnosed in more detail based on the correspondence between multiple target values.

[0103] The curve acquisition unit 110 and control unit 120 equipped in the battery diagnostic device 100 may optionally include processors, application-specific integrated circuits (ASICs), another chipset, logic circuits, registers, communication modems, and data processing devices known in the art to execute the various control logics performed in this disclosure. Furthermore, when the control logic is implemented as software, the curve acquisition unit 110 and control unit 120 may be implemented as a set of program modules. In this case, the program modules may be stored in memory and executed by the curve acquisition unit 110 and control unit 120. The memory may be located internally or externally to the curve acquisition unit 110 and control unit 120 and may be connected to the curve acquisition unit 110 and control unit 120 by various well-known means.

[0104] The battery diagnostic device 100 may also include a storage unit 130. The storage unit 130 may store data or programs required for each component of the battery diagnostic device 100 to perform operations and functions, or data generated during the performance of operations and functions. The storage unit 130 is not particularly limited in type, as long as it is a known information storage device capable of recording, erasing, updating, and retrieving data. In examples, the information storage device may include random access memory (RAM), flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and registers. Furthermore, the storage unit 130 may store program code defining processes that can be executed by the curve acquisition unit 110 and the control unit 120.

[0105] For example, storage unit 130 can store battery information, battery curve BP, differential curve, and battery diagnostic information provided by control unit 120.

[0106] The control unit 120 can be configured to control the battery based on diagnostic results regarding the battery's state. For example, the control unit 120 can change the battery's usage conditions based on the diagnostic results.

[0107] In the example, the control unit 120 can be configured to reduce the battery's state to at least one of a set upper limit C-rate and a constant voltage charging time when the battery's state is diagnosed as either a positive electrode degradation state or a positive or negative electrode degradation state. For example, when positive electrode degradation of the battery is diagnosed, the control unit 120 can change the battery's operating conditions to suppress further degradation of the battery's positive electrode.

[0108] In another example, the control unit 120 can be configured to reduce the battery's charging upper limit voltage to a predefined value when the battery's state is diagnosed as negative electrode degradation or both positive and negative electrode degradation. When negative electrode degradation is diagnosed, the control unit 120 can change the battery's operating conditions to suppress further degradation of the battery's negative electrode.

[0109] By changing the usage conditions of the battery, the degradation of the positive and / or negative electrodes can be slowed down, thereby increasing the expected lifespan of the battery.

[0110] The control unit 120 can be configured to divide the capacity segment into a first segment R1 and a second segment R2 based on a preset division ratio or target capacity.

[0111] In one embodiment, the control unit 120 may divide the capacity segments based on a preset ratio. For example, the control unit 120 may divide the capacity segments at a ratio of n:m (where n and m are positive numbers) to set the lower capacity segment as the first segment R1 and the higher capacity segment as the second segment R2.

[0112] For example, suppose the starting capacity is Qi and the ending capacity is Qf. Also, suppose the capacity corresponding to the ratio n:m is Qk, then Qk can be calculated using the formula "(Qf-Qi)÷(n+m)×n". The control unit 120 can set the capacity segment from Qi to Qk as the first segment R1. Furthermore, the control unit 120 can set the capacity segment from Qk to Qf as the second segment R2.

[0113] In another embodiment, the control unit 120 can distinguish capacity segments by using a differential curve based on the battery curve BP.

[0114] The curve acquisition unit 110 can be configured to further acquire the differential curve corresponding to the battery curve BP.

[0115] For example, when the battery curve BP is differentiated relative to the capacity, a differential curve indicating the correspondence between the differential voltage dV / dQ and the capacity Q can be generated. Furthermore, when the battery curve BP is differentiated relative to the voltage, a differential curve indicating the correspondence between the differential capacity dQ / dV and the voltage V can be generated.

[0116] For example, curve acquisition unit 110 can directly read or receive the differential curve of the battery from an external source. For example, curve acquisition unit 110 can acquire the differential curve BP by connecting to an external source via a wired and / or wireless connection and reading or receiving the differential curve.

[0117] In another example, the curve acquisition unit 110 can directly read or receive the battery curve BP from an external source and generate a differential curve based on the battery curve BP. For example, the curve acquisition unit 110 can be connected to an external source via wired and / or wireless means to read or receive the battery curve BP and directly generate a differential curve based on the corresponding battery curve BP, thereby acquiring the differential curve.

[0118] In another example, curve acquisition unit 110 can generate a battery curve BP based on battery information about the battery's voltage and capacity, and generate a differential curve based on the generated battery curve BP. In this way, curve acquisition unit 110 can directly generate a differential curve based on battery information, thereby acquiring the differential curve.

[0119] The curve acquisition unit 110 can be communicatively connected to the control unit 120. For example, the curve acquisition unit 110 can be wired or wirelessly connected to the control unit 120. In one example, the curve acquisition unit 110 can send the acquired differential curve to the control unit 120. In another example, the control unit 120 can read the differential curve from the curve acquisition unit 110.

[0120] In one embodiment, the differential curve acquired by the curve acquisition unit 110 can be configured to represent the correspondence between the battery capacity Q and the differential voltage dV / dQ.

[0121] Figure 5 This is a schematic diagram illustrating a differential curve DP according to an embodiment of the present disclosure. Figure 5 In some embodiments, the differential curve DP can be expressed as an XY curve, where the X-axis is set to the capacitance Q and the Y-axis is set to the differential voltage dV / dQ. For example, Figure 5 The differential curve DP has the same characteristics as Figure 3 It has the same shape as the first differential curve.

[0122] The control unit 120 can be configured to determine the main peak tp in the differential curve DP.

[0123] For example, the control unit 120 can be configured to determine multiple local minimum points in the differential curve DP. For example, in Figure 5 In the embodiments, the differential curve DP may include first to fifth local minimum points p1, p2, p3, p4, and p5.

[0124] According to one embodiment, the control unit 120 can be configured to identify the local minimum point with the smallest corresponding differential voltage among a plurality of determined local minimum points as the main peak tp. For example, in Figure 5In the embodiment, since the differential voltage corresponding to the third local minimum point p3 is the smallest among multiple local minimum points p1, p2, p3, p4, p5, the control unit 120 can determine the third local minimum point p3 as the main peak tp.

[0125] The control unit 120 can be configured to divide capacity segments based on the capacity of the determined peak tp. For example, in Figure 5 In one embodiment, when the capacity of the main peak tp is Qk, the control unit 120 can divide the capacity segment into a first segment R1 from Qi to Qk and a second segment R2 from Qk to Qf.

[0126] Generally, based on the local minimum point where the differential voltage is minimum, the low-capacity side reflects the state of the negative electrode of the battery, and the high-capacity side reflects the state of the positive electrode of the battery. Therefore, the control unit 120 can distinguish the capacity segments of the battery curve not only based on a certain ratio (n:m), but also based on the main peak tp.

[0127] In another example, the control unit 120 may identify the local minimum point with the minimum differential voltage, which is included in the lower-middle capacity segment of the battery curve, as the main peak tp.

[0128] Generally, when the capacity range of a battery curve is divided into low-capacity and high-capacity ranges, the local minimum point with the minimum differential voltage is included in the low-capacity range. Therefore, the control unit 120 can determine the main peak tp in the lower-middle capacity range (low-capacity range) of the battery. For example, the control unit 120 can save the time and system resources required to determine the main peak tp by determining it among multiple local minimum points included in the low-capacity range.

[0129] For example, in Figure 5 In this embodiment, the low-capacity segment includes first to third local minimum points p1, p2, and p3. The control unit 120 can determine the third local minimum point p3, which has the smallest differential voltage among the first to third local minimum points p1, p2, and p3, as the main peak tp.

[0130] In this way, because the number of local minima included in the entire capacity range and the low capacity range is different, the time and system resources required to compare the differential voltages of multiple local minima may also differ. Therefore, the control unit can determine the main peak more quickly by considering only the local minima included in the low capacity range.

[0131] In another embodiment, the differential curve DP acquired by the curve acquisition unit 110 can be configured to represent the correspondence between the battery voltage V and the differential capacity dQ / dV.

[0132] The control unit 120 can be configured to determine multiple local maximum points in the differential curve DP. A local maximum point is the opposite of a local minimum point and refers to a point in the differential curve DP that has an upward convex shape.

[0133] Furthermore, the control unit 120 can be configured to identify the local maximum point with the largest corresponding differential voltage among the determined plurality of local maximum points as the main peak.

[0134] The battery diagnostic device 100 according to this disclosure can be applied to a battery management system (BMS). For example, a BMS according to this disclosure may include the battery diagnostic device 100 described above. With this configuration, at least some of the components of the battery diagnostic device 100 can be implemented by supplementing or adding the functionality of components included in a conventional BMS. For example, the curve acquisition unit 110, control unit 120, and storage unit 130 of the battery diagnostic device 100 can be implemented as components of a BMS.

[0135] Furthermore, the battery diagnostic device 100 according to this disclosure can be equipped in a battery pack. Additionally, the battery pack according to this disclosure may include the aforementioned battery diagnostic device 100 and one or more individual battery cells. Furthermore, the battery pack may also include, for example, electrical components (e.g., relays and fuses) and a housing.

[0136] Figure 6 This is a schematic diagram illustrating a battery pack 10 according to another embodiment of the present disclosure.

[0137] The positive terminal of battery 11 can be connected to the positive terminal P+ of battery pack 10, and the negative terminal of battery 11 can be connected to the negative terminal P- of battery pack 10.

[0138] The measuring unit 12 can be connected to a first sensing line SL1, a second sensing line SL2, and a third sensing line SL3. For example, the measuring unit 12 can be connected to the positive terminal of the battery 11 via the first sensing line SL1 and to the negative terminal of the battery 11 via the second sensing line SL2. The measuring unit 12 can measure the voltage of the battery 11 based on the voltage measured at each of the first sensing line SL1 and the second sensing line SL2.

[0139] Then, the measurement unit 12 can be connected to the current measurement unit A via the third sensing line SL3. For example, the current measurement unit A can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 11. The measurement unit 12 can measure the charging current of the battery 11 via the third sensing line SL3 to calculate the amount of charge. In addition, the measurement unit 12 can measure the discharging current of the battery 11 via the third sensing line SL3 to calculate the amount of discharge.

[0140] For example, the curve acquisition unit 110 can read or receive battery information about the battery voltage and current from the measurement unit 12, and generate the battery curve BP and the differential curve DP based on the battery information.

[0141] In another example, the curve acquisition unit 110 can read or receive the battery curve BP from the measurement unit 12 and generate the differential curve DP based on the battery curve BP.

[0142] In another example, curve acquisition unit 110 can read or receive differential curve DP from measurement unit 12.

[0143] An external device can be connected to the positive terminal P+ and the negative terminal P- of the battery pack 10. For example, the external device can be a charging device or a load. Furthermore, the positive terminal of the battery 11, the positive terminal P+ of the battery pack 10, the external device, the negative terminal P- of the battery pack 10, and the negative terminal of the battery 11 can be electrically connected.

[0144] Figure 7 This is a schematic diagram of a vehicle 700 according to another embodiment of the present disclosure.

[0145] refer to Figure 7 According to one embodiment of the present disclosure, a battery pack 710 can be included in a vehicle 700, such as an electric vehicle (EV) or a hybrid vehicle (HV). Furthermore, the battery pack 710 can drive the vehicle 700 by supplying power to a motor via an inverter installed in the vehicle 700. Here, the battery pack 710 installed in the vehicle may include a battery diagnostic device 100 according to one embodiment of the present disclosure. In this case, the battery diagnostic device 100 may be an on-board device included in the vehicle 700.

[0146] Figure 8 This is a schematic diagram illustrating a battery diagnostic method according to another embodiment of the present disclosure.

[0147] refer to Figure 8 The battery diagnostic method may include a curve acquisition step (S100), a segment division step (S200), a target value derivation step (S300), a comparison step (S400), and a diagnostic step (S500).

[0148] Each step of the battery diagnostic method can be performed by the battery diagnostic device 100. In the following text, for ease of explanation, any content overlapping with the previously described content will be omitted or briefly described.

[0149] The curve acquisition step (S100) is a step of acquiring the battery curve BP, which represents the correspondence between the battery's voltage and capacity, and can be executed by the curve acquisition unit 110.

[0150] For example, the curve acquisition unit 110 can directly read or receive the battery curve BP from an external source. For example, the curve acquisition unit 110 can acquire the battery curve BP by connecting to an external source via a wired and / or wireless connection and reading or receiving the battery curve BP.

[0151] In another example, curve acquisition unit 110 can generate a battery curve BP based on battery information about the battery's voltage and capacity. In this way, curve acquisition unit 110 can acquire the battery curve BP by directly generating the battery curve BP based on the read or received battery information.

[0152] The segmentation step (S200) is a step of dividing the capacity segment of the battery curve BP into multiple segments, and can be executed by the control unit 120.

[0153] According to one embodiment, the control unit 120 can divide the entire capacity range of the battery curve BP into two or more segments. For example, in Figure 2 In this embodiment, the entire capacity range of the battery curve BP is Qi to Qf. The control unit 120 can divide the capacity range of Qi to Qf into a first segment R1 and a second segment R2 based on Qk.

[0154] The target value derivation step (S300) is a step of deriving the target value of a target indicator related to the differential capacitance peak or resistance among a plurality of preset diagnostic indicators in each segment, and can be executed by the control unit 120.

[0155] For example, in Figure 3 In one embodiment, the control unit 120 can select a target indicator for each of the first segment R1 and the second segment R2. Then, the control unit 120 can derive the target value corresponding to the selected target indicator.

[0156] The comparison step (S400) is a step of comparing the correspondence between multiple derived target values ​​with a preset reference curve representing the correspondence between multiple target indicators, and can be executed by the control unit 120.

[0157] According to one embodiment, when the capacity segment of the battery curve BP is divided into a first segment R1 and a second segment R2, and a first target value of the target index is derived in the first segment R1 and a second target value of the target index is derived in the second segment R2, the control unit 120 can compare the target point representing the correspondence between multiple target values ​​with the reference curve.

[0158] For example, in Figure 4In one embodiment, the control unit 120 can determine whether the target point is included in the reference curve. When the target point is not included in the reference curve, the control unit 120 can determine which of the first region T1, the second region T2, and the third region T3 the target point is included in.

[0159] Diagnostic step S500 is a step to diagnose the state of the battery based on the comparison results, and can be executed by control unit 120.

[0160] For example, in Figure 4 In one embodiment, the control unit 120 can diagnose the battery state as a deterioration state of both positive and negative electrodes when the target point is included in the reference curve.

[0161] In another example, the control unit 120 can diagnose the battery state as a negative electrode deterioration state when the target point is included in the first region T1.

[0162] In yet another example, the control unit 120 can diagnose the battery state as a positive electrode deterioration state when the target point is included in the second region T2.

[0163] In another example, the control unit 120 can diagnose the battery state as EOL when the target point is included in the third region T3.

[0164] The embodiments of this disclosure described above can be implemented not only by apparatus and methods, but also by programs that implement the functions corresponding to the components of the embodiments of this disclosure, or by recording media that store the programs. Such implementation can be readily carried out by those skilled in the art to which this disclosure pertains, based on the description of the above embodiments.

[0165] Although this disclosure has been described with limited embodiments and drawings, it is not limited thereto, and it will be understood that those skilled in the art can make various modifications and changes within the scope of the technical concept of this disclosure and the equivalents of the claims set forth below.

[0166] Furthermore, since those skilled in the art can make various substitutions, modifications and changes without departing from the technical concept of this disclosure, the above disclosure is not limited to the foregoing embodiments and drawings, but can selectively combine all or part of the embodiments to achieve various modifications.

[0167] (Explanation of the labels in the attached diagram)

[0168] 10: Battery Pack

[0169] 11: Battery

[0170] 12: Measurement Unit

[0171] 100: Battery diagnostic device

[0172] 110: Curve Acquisition Unit

[0173] 120: Control Unit

[0174] 130: Storage unit

[0175] 700: Vehicles

[0176] 710: Battery Pack

Claims

1. A battery diagnostic device, comprising: A curve acquisition unit is configured to acquire a battery curve representing the relationship between the battery's voltage and capacity. as well as The control unit is configured to divide the capacity segment of the battery curve into multiple segments, derive a target value of a target indicator related to the differential capacity peak or resistance from a plurality of pre-set diagnostic indicators from each segment, compare the correspondence between the derived multiple target values ​​with a preset reference curve representing the correspondence between the multiple target indicators, and diagnose the state of the battery based on the result of the comparison.

2. The battery diagnostic device according to claim 1, wherein, The control unit is configured to: The number of differential capacity peaks included in the differential curve corresponding to the battery curve and representing the relationship between voltage and differential capacity, the area of ​​the differential curve, the voltage of the main peak among the multiple differential capacity peaks, or the differential capacity of the main peak are determined as target indicators corresponding to the low-capacity segment among the multiple segments, and The resistor is determined as a target indicator corresponding to the high-capacity segment among the plurality of segments.

3. The battery diagnostic device according to claim 1, wherein, The control unit is configured to: When the target point indicating the correspondence between the plurality of target values ​​is included in the reference curve, the state of the battery is diagnosed as a state of positive and negative electrode degradation. When the target point is included in the first region based on the reference curve, the state of the battery is diagnosed as a negative electrode degradation state, and The state of the battery is diagnosed as positive electrode deterioration when the target point is included in the second region based on the reference curve.

4. The battery diagnostic device according to claim 3, wherein, The control unit is configured to diagnose the battery's state as end-of-life when the target point is included in the third region, and The third region is configured to be a region that exceeds a preset threshold for each of the plurality of target indicators.

5. The battery diagnostic device according to claim 3, wherein, The control unit is configured to reduce the current rate to at least one of the upper limit current rate and constant voltage charging time set for the battery when the state of the battery is diagnosed as either the positive electrode deterioration state or the positive or negative electrode deterioration state.

6. The battery diagnostic device according to claim 3, wherein, The control unit is configured to reduce the battery's charging upper limit voltage to a value set by the battery when the battery's state is diagnosed as either a negative electrode deterioration state or a positive or negative electrode deterioration state.

7. The battery diagnostic device according to claim 1, wherein, The control unit is configured to divide the capacity segment into a first segment and a second segment based on a preset division ratio or target capacity.

8. The battery diagnostic device according to claim 7, wherein, The curve acquisition unit is configured to further acquire the differential curve corresponding to the battery curve, and The control unit is configured to determine the main peak based on the differential curve and to divide the capacity segment based on the capacity of the determined main peak.

9. The battery diagnostic device according to claim 8, wherein, The differential curve is configured to represent the correspondence between the battery's capacity and its differential voltage, and The control unit is configured to determine a plurality of local minimum points in the differential curve, and to determine the local minimum point with the smallest corresponding differential voltage among the determined plurality of local minimum points as the main peak.

10. The battery diagnostic device according to claim 8, wherein, The differential curve is configured to represent the correspondence between the battery's voltage and its differential capacity, and The control unit is configured to determine a plurality of local maximum points in the differential curve, and to determine the local maximum point with the largest corresponding differential voltage among the determined plurality of local maximum points as the main peak.

11. A battery pack comprising a battery diagnostic device according to any one of claims 1 to 10.

12. A vehicle comprising a battery diagnostic device according to any one of claims 1 to 10.

13. A battery diagnostic method, comprising: The curve acquisition step involves acquiring a battery curve that represents the relationship between the battery's voltage and capacity. The segmentation step divides the capacity segment of the battery curve into multiple segments; The target value derivation step derives the target value of one of a plurality of pre-defined diagnostic indicators related to the differential capacity peak or resistance from each of the divided segments. The comparison step compares the correspondence between the derived multiple target values ​​with a preset reference curve representing the correspondence between the multiple target indicators. as well as A diagnostic step, which diagnoses the state of the battery based on the results of the comparison.

14. A non-transitory computer-readable storage medium storing a program therein, the program, when executed, causing a computer to perform a battery diagnostic method, the battery diagnostic method comprising: The curve acquisition step involves acquiring a battery curve that represents the relationship between the battery's voltage and capacity. The segmentation step divides the capacity segment of the battery curve into multiple segments; The target value derivation step derives the target value of one of a plurality of pre-defined diagnostic indicators related to the differential capacity peak or resistance from each of the divided segments. The comparison step compares the correspondence between the derived multiple target values ​​with a preset reference curve representing the correspondence between the multiple target indicators. as well as A diagnostic step, which diagnoses the state of the battery based on the results of the comparison.

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