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 differential curve indicating a correspondence relationship between a capacity of a battery and a differential voltage; a curve correction unit that determines a target C-rate (current rate) corresponding to the differential curve, and corrects the differential curve based on an overvoltage curve corresponding to the target C-rate, thereby generating a correction curve; and a control unit that determines a first target peak and a second target peak in the correction curve, and diagnoses a state of the battery based on a behavior of the first target peak and a behavior of the second target peak.

Description

Technical Field

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2024-0012287, filed with the Korean Intellectual Property Office on January 26, 2024, the disclosure of which is incorporated herein by reference in its entirety.

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

[0003] Recently, with the rapid growth in demand for portable electronic products such as laptops, video cameras and mobile phones, as well as the accelerated 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 attracted considerable attention compared to nickel-based batteries due to their advantages, including significantly low memory effect allowing for greater freedom in charging and discharging, 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 important. 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 for diagnosing the current state of a battery.

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

[0009] Technical solution

[0010] A battery diagnostic apparatus according to one aspect of the present disclosure may include: a curve acquisition unit that acquires a differential curve representing the correspondence between the battery's capacity and differential voltage; a curve correction unit that determines a target C-rate (current rate) corresponding to the differential curve and corrects the differential curve based on an overvoltage curve corresponding to the target C-rate, thereby generating a correction curve; and a control unit that diagnoses the battery's state based on the shape of a target capacity segment of the correction curve.

[0011] The control unit can be configured to identify the minimum point with the minimum corresponding capacity among the multiple minimum points included in the calibration curve as the target peak, and to set the target capacity range based on the target differential voltage corresponding to the target peak.

[0012] The control unit can be configured to determine a reference point in the calibration curve that corresponds to the target differential voltage and is closest to the target peak, and to set the capacity range from the target peak to the reference point as the target capacity range.

[0013] The control unit can be configured such that when the differential capacity of the target peak is less than the differential capacity of the second minimum point among a plurality of minimum points having a second minimum corresponding capacity, the differential voltage corresponding to the second minimum point is set as the target differential voltage.

[0014] The control unit can be configured to determine a reference point in the calibration curve that corresponds to the target differential voltage and is closest to the second minimum point, and to set the capacity range from the reference point to the second minimum point as the target capacity range.

[0015] The control unit can be configured to divide the target capacity segment into a low-capacity segment and a high-capacity segment, and diagnose the state of the battery based on the segment in the target capacity segment that includes the feature point with the maximum corresponding differential voltage.

[0016] The control unit can be configured to diagnose the battery state as a state of available lithium loss when the feature point is included in the high-capacity section.

[0017] The curve correction unit can be configured to calculate the difference between the differential curve and the overvoltage curve to generate a correction curve.

[0018] Overvoltage curves are configured to be pre-stored for each of the multiple C-rates.

[0019] The curve correction unit can be configured to select an overvoltage curve corresponding to the target C rate from a plurality of pre-stored overvoltage curves.

[0020] The overvoltage curve can be preset based on the reference differential curve of the reference cell with respect to the reference C rate and the target differential curve of the reference cell with respect to the target C rate.

[0021] The overvoltage curve can be preset to represent the difference between the reference differential curve and the target differential curve.

[0022] According to another aspect of this disclosure, a battery pack may include a battery diagnostic device according to one aspect of this disclosure.

[0023] A vehicle according to another aspect of this disclosure may include a battery diagnostic device according to one aspect of this disclosure.

[0024] A battery diagnostic method according to another aspect of this disclosure may include: a curve acquisition step, which acquires a differential curve representing the correspondence between the battery capacity and the differential voltage; a target determination step, which determines a target C-rate corresponding to the differential curve; a correction curve generation step, which corrects the differential curve based on an overvoltage curve corresponding to the target C-rate to generate a correction curve; and a battery diagnostic step, which diagnoses the state of the battery based on the shape of the target capacity segment of the correction curve.

[0025] According to another aspect of the present disclosure, the battery diagnostic method may further include a target peak determination step, which determines the minimum point with the minimum corresponding capacity among a plurality of minimum points included in the calibration curve as the target peak, and sets a target capacity range based on the target differential voltage corresponding to the target peak.

[0026] The target peak determination step may include identifying a reference point in the calibration curve that corresponds to the target differential voltage and is closest to the target peak, and setting the capacity range from the target peak to the reference point as the target capacity range.

[0027] According to another aspect of this disclosure, a non-transitory computer-readable storage medium may store therein a program for performing a battery diagnostic method, the battery diagnostic method comprising: a curve acquisition step, which acquires a differential curve representing the correspondence between the battery capacity and differential voltage; a target determination step, which determines a target C-rate corresponding to the differential curve; a correction curve generation step, which corrects the differential curve based on an overvoltage curve corresponding to the target C-rate to generate a correction curve; and a battery diagnostic step, which diagnoses the state of the battery based on the shape of a target capacity segment of the correction curve.

[0028] According to another aspect of this disclosure, a non-transitory computer-readable storage medium may store therein a program for performing a battery diagnostic method, the battery diagnostic method further comprising a target peak determination step for determining the minimum point with the minimum corresponding capacity among a plurality of minimum points included in a calibration curve as a target peak, and setting a target capacity range based on a target differential voltage corresponding to the target peak.

[0029] Beneficial effects

[0030] According to one aspect of this disclosure, the state of the battery is diagnosed based on a calibration curve, making it possible to diagnose the battery state relatively quickly.

[0031] The effects of this disclosure are not limited to those described above, and other effects not described herein will be clearly understood by those skilled in the art from the description in the claims. Attached Figure Description

[0032] Since the accompanying drawings are provided to facilitate understanding of the technical concept of this disclosure in conjunction with the following detailed description of the invention, this disclosure should not be construed as being limited to the contents shown in the drawings.

[0033] Figure 1 This is a schematic view of a battery diagnostic device according to an embodiment of the present disclosure.

[0034] Figure 2 This is a schematic view illustrating a battery curve according to an embodiment of the present disclosure.

[0035] Figure 3 This is a schematic view of a differential curve according to an embodiment of the present disclosure.

[0036] Figure 4 This is a schematic view illustrating the differential curve and the correction curve according to an embodiment of the present disclosure.

[0037] Figure 5 This is a schematic view illustrating a correction curve according to an embodiment of the present disclosure.

[0038] Figure 6 This is a view schematically illustrating a plurality of calibration curves of a first battery according to an embodiment of the present disclosure.

[0039] Figure 7 This is a schematic view showing the battery state corresponding to a plurality of calibration curves of a second battery according to an embodiment of the present disclosure.

[0040] Figure 8 This is a schematic view of a battery pack according to another embodiment of the present disclosure.

[0041] Figure 9 This is a schematic view of a vehicle according to yet another embodiment of the present disclosure.

[0042] Figure 10 This is a schematic view illustrating a battery diagnostic method according to another embodiment of the present disclosure. Detailed Implementation

[0043] 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 purpose of best describing the present disclosure.

[0044] Therefore, it can be understood that the embodiments described herein and the configurations shown in the accompanying drawings are merely examples of this disclosure, and they do not exhaustively represent the technical ideas of this disclosure. Furthermore, various equivalents and modifications can be made to replace this disclosure at the time of submission.

[0045] In describing this disclosure, a detailed description may be omitted if it is determined that the essential points of this disclosure are obscured by a detailed description of the relevant known configuration or function.

[0046] Terms with ordinal numbers such as first, second, etc., can be used to distinguish one component from another, but should not be interpreted as restricting these components.

[0047] Throughout this description, when a section “includes” a particular component, this description does not indicate that the section excludes other components, but rather that the section may also include other components, unless otherwise specified.

[0048] Furthermore, throughout this description, when two components are “connected” to each other, this 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.

[0049] Figure 1 This is a schematic view of a battery diagnostic device 100 according to an embodiment of the present disclosure.

[0050] refer to Figure 1 The battery diagnostic device 100 may include a curve acquisition unit 110, a curve correction unit 120, a control unit 130, and a storage unit 140.

[0051] A battery can refer to a single, physically separable, 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. Battery types can be cylindrical, prismatic, or pouch-shaped. Furthermore, a battery can refer to 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 is assumed that a battery refers to a single, isolated cell.

[0052] The curve acquisition unit 110 can be configured to acquire a differential curve DP representing the relationship between the battery voltage and differential capacity.

[0053] For example, the battery curve BP represents the relationship between the battery's voltage (V) and capacity (Q) as the battery is charged from a preset start-of-charge state of charge (SOC) or 0% to a preset end-of-charge state of charge (SOC) or 100%. In another example, the battery curve BP could represent the relationship between the battery's voltage (V) and capacity (Q) as the battery is discharged from a preset start-of-discharge state of charge (SOC) or 100% to a preset end-of-discharge state of charge (SOC) or 0%.

[0054] Figure 2 This is a schematic view illustrating the battery curve BP according to one embodiment of the present disclosure. Figure 2 In one embodiment, the battery curve BP can be represented as an XY curve, where the X-axis is set to capacity (Q) and the Y-axis is set to voltage (V).

[0055] Then, when the battery curve BP is differentiated relative to the capacity, a differential curve DP can be generated, which represents the correspondence between the differential voltage (dV / dQ) and the capacity (Q).

[0056] Figure 3 This is a schematic view illustrating a differential curve DP according to an embodiment of the present disclosure. Figure 3 In one embodiment, the differential curve DP can be represented as an XY curve, where the X-axis is set to capacitance (Q) and the Y-axis is set to differential voltage (dV / dQ).

[0057] For example, there is no particular limitation on the charging or discharging rate (C rate) used to generate the battery curve BP. According to one embodiment, in order to obtain a more accurate battery curve BP and differential curve DP, the battery needs to be charged or discharged at a low rate. For example, the battery curve BP can be generated during the process of charging or discharging the battery at a relatively low rate (such as 0.05C).

[0058] According to one embodiment, the curve acquisition unit 110 can directly receive the differential curve DP of the battery from an external source. For example, the curve acquisition unit 110 can acquire the differential curve DP by connecting to an external source via a wired and / or wireless network.

[0059] In another example, the curve acquisition unit 110 can directly generate the differential curve DP by receiving the battery curve BP from an external source and differentiating the received battery curve BP relative to the capacity. According to one embodiment, the curve acquisition unit 110 can obtain the differential curve DP by connecting to an external source via a wired and / or wireless connection to receive the battery curve BP and directly generating the differential curve DP based on the received battery curve BP.

[0060] In another example, the curve acquisition unit 110 can receive battery information about the battery's voltage and capacity from the outside, generate a battery curve BP directly based on the received battery information, and generate a differential curve DP directly based on the generated battery curve BP.

[0061] According to one embodiment, the curve acquisition unit 110 can be connected to the control unit 130 for communication. For example, the curve acquisition unit 110 can be connected to the control unit 130 via wired or wireless means. The curve acquisition unit 110 can send the acquired differential curve DP to the control unit 130.

[0062] According to one embodiment, the curve correction unit 120 can be configured to determine a target C rate corresponding to the differential curve DP.

[0063] According to one embodiment, the curve correction unit 120 can simultaneously acquire the differential curve DP and information about the corresponding target C rate.

[0064] For example, when the battery is charged at 0.33C, the target C rate corresponding to the differential curve DP can be 0.33C. The curve correction unit 120 can receive the differential curve DP and information about 0.33C from the curve acquisition unit 110. Then, the curve correction unit 120 can determine 0.33C corresponding to the differential curve DP as the target C rate.

[0065] The curve correction unit 120 can be configured to correct the differential curve DP based on the overvoltage curve corresponding to the target C rate, and generate a correction curve CP.

[0066] According to one embodiment, the overvoltage curve can be preset to represent the overvoltage portion included in the differential curve DP. For example, the overvoltage curve OP can be preset based on a reference differential curve DP of the reference battery with respect to a reference C rate and a target differential curve DP of the reference battery with respect to a target C rate. According to one embodiment, the target C rate can be set to be greater than the reference C rate. Furthermore, the overvoltage curve can be preset to represent the difference between the reference differential curve DP and the target differential curve DP.

[0067] For example, when the reference C-rate is 0.05C and the target C-rate is 0.33C, when the reference battery is charged (or discharged) at 0.05C, a reference battery curve BP for the reference C-rate can be obtained, and a reference differential curve DP can be obtained based on the reference battery curve BP. Furthermore, when the reference battery is charged (or discharged) at 0.33C, a target battery curve BP for the target C-rate can be obtained, and a target differential curve DP can be obtained based on the target battery curve BP. Then, an overvoltage curve corresponding to the 0.33C C-rate can be generated based on the difference between the reference differential curve DP and the target differential curve DP. When the battery is charged or discharged at a target C-rate greater than the reference C-rate, the measured battery voltage may include overvoltage. Therefore, the curve correction unit 120 can remove the reference differential curve DP based on the reference C-rate from the target differential curve DP based on the target C-rate to generate an overvoltage curve.

[0068] Then, the curve correction unit 120 can be configured to select an overvoltage curve corresponding to the target C rate from a plurality of pre-stored overvoltage curves.

[0069] Overvoltage profiles can be pre-stored for each of the multiple C-rates.

[0070] According to one embodiment, multiple overvoltage curves can be provided, and the C-rates corresponding to the multiple overvoltage curves can be different from each other. For example, based on a single C-rate, the overvoltage curves corresponding to the respective C-rates can be stored in advance.

[0071] Furthermore, overvoltage curves for C-rates not obtained experimentally can be acquired and stored by interpolation or extrapolation between similar overvoltage curves. For example, in addition to pre-stored overvoltage curves, curve correction unit 120 can also generate overvoltage curves for various C-rates by interpolation or extrapolation and store the generated overvoltage curves in storage unit 140. For example, when overvoltage curves corresponding to a C-rate of 1C and overvoltage curves corresponding to a C-rate of 1.2C are pre-stored, an overvoltage curve corresponding to a C-rate of 1.1C can be further acquired based on the difference between these two overvoltage curves.

[0072] The curve correction unit 120 can be configured to calculate the difference between the differential curve DP and the overvoltage curve to generate a correction curve CP.

[0073] For example, the curve correction unit 120 can generate a correction curve CP by calculating the difference between the differential curve DP and the overvoltage curve in the same way as generating an overvoltage curve based on the difference between the reference differential curve DP and the target differential curve DP.

[0074] Furthermore, the curve correction unit 120 can generate a correction curve CP by calculating the differential capacity difference for each voltage between the differential curve DP and the overvoltage curve.

[0075] Figure 4 This is a schematic view illustrating the differential curve DP and the correction curve CP according to an embodiment of the present disclosure. Figure 5 This is a schematic view of a correction curve CP according to an embodiment of the present disclosure.

[0076] exist Figure 4 In one embodiment, the correction curve CP can be generated based on the differential voltage difference for each capacity between the differential curve DP and the corresponding overvoltage curve (not shown). According to one embodiment, the curve correction unit 120 can calculate the difference between the differential curve DP and the overvoltage curve to generate a correction curve CP in which the overvoltage portion included in the differential curve DP has been removed.

[0077] The control unit 130 can be configured to diagnose the state of the battery based on the shape of the target capacity segment TR of the calibration curve CP. Here, the target capacity segment TR refers to the capacity segment in which the state of the battery can be diagnosed based on its shape, and an embodiment in which the control unit 130 sets the target capacity segment TR will be described later.

[0078] refer to Figure 5 The control unit 130 can diagnose the battery's state based on whether the shape of the target capacity segment TR has changed. For example, the control unit 130 can determine whether the shape of the target capacity segment TR has changed and diagnose the battery's state based on the determination result.

[0079] For example, control unit 130 can diagnose whether the battery's available lithium has been lost. For example, when it is determined that the shape of the target capacity segment TR has changed, control unit 130 can diagnose the battery's state as a state of available lithium loss.

[0080] Here, the lithium loss state can be used to indicate the state in which the amount of lithium participating in the charging and discharging of the battery has been lost compared to its initial state due to various reasons. For example, the lost lithium may deposit as lithium metal on the surface of the battery's negative electrode. This phenomenon is called lithium plating (Li plating). When lithium plating becomes severe, a short circuit occurs in the battery, which can cause unexpected and serious problems such as fires and explosions.

[0081] According to one embodiment of this disclosure, a battery diagnostic apparatus 100 can use an overvoltage curve to derive a calibration curve CP relatively quickly, based on which the battery state can be diagnosed. Then, the battery diagnostic apparatus 100 can diagnose the battery state solely based on the shape of the target capacity segment TR in the calibration curve CP, enabling faster battery state diagnosis. According to this disclosure, it is possible to quickly diagnose whether the battery's usable lithium has been lost, and therefore, accidents caused by lithium plating can be prevented or suppressed in advance.

[0082] Meanwhile, the curve acquisition unit 110, curve correction unit 120, and control unit 130 disposed in the battery diagnostic device 100 may optionally include, for example, processors, application-specific integrated circuits (ASICs), other chipsets, logic circuits, registers, communication modems, and data processing devices well known in the art, to execute the various control logics performed in this disclosure. When the control logic is implemented by software, the curve correction unit 120 can be implemented as a set of program modules. In this case, the program modules can be stored in memory and executed by the curve acquisition unit 110, curve correction unit 120, and control unit 130. The memory can be disposed inside or outside the curve acquisition unit 110, curve correction unit 120, and control unit 130, and can be connected to the curve acquisition unit 110, curve correction unit 120, and control unit 130 by various well-known means.

[0083] The battery diagnostic device 100 may also include a storage unit 140. The storage unit 140 may store, for example, data or programs required by each component of the battery diagnostic device 100 to perform its operation and functions, or data generated during the performance of its operation and functions. The type of storage unit 140 is not particularly limited, as long as it is a well-known information storage device capable of recording, erasing, updating, and retrieving data. Information storage devices may include, for example, random access memory (RAM), flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and registers. Furthermore, the storage unit 140 may store program code defining processes that can be executed by the curve acquisition unit 110, the curve correction unit 120, and the control unit 130.

[0084] Storage unit 140 can store battery curve BP, differential curve DP, and correction curve CP.

[0085] The following describes an embodiment in which the control unit 130 diagnoses the state of the battery.

[0086] The control unit 130 can be configured to divide the target capacity segment TR into a low-capacity segment and a high-capacity segment.

[0087] According to one embodiment, the control unit 130 can divide a target capacity segment TR into two parts to distinguish between a low-capacity segment and a high-capacity segment. For example, the low-capacity segment and the high-capacity segment have the same segment size (the size of the capacity range). Here, the segment size refers to the difference between the upper and lower capacity limits of the corresponding segment, and is a factor different from the area of ​​the corresponding segment.

[0088] For example, suppose the target capacity segment TR is the capacity segment from Qn to Qm. The control unit 130 can set the capacity segment from Qn to (Qm-Qn) / 2 as a low capacity segment and set the capacity segment from (Qm-Qn) / 2 to Qm as a high capacity segment.

[0089] Figure 6 A view schematically illustrating a plurality of calibration curves CP of a first battery according to an embodiment of the present disclosure. For example, Figure 6 The view represents multiple calibration curves (CP) of the first cell as it loses available lithium during cycling. For example, Figure 6 The calibration curve CP represents the first battery corresponding to the initial cycle (ini), the 10th cycle, the 40th cycle, the 60th cycle, and the 90th cycle.

[0090] exist Figure 6 In this embodiment, the target capacity segment TR can be divided into a low-capacity segment LQ and a high-capacity segment HQ. Here, the low-capacity segment LQ and the high-capacity segment HQ have the same segment size.

[0091] According to one embodiment, the control unit 130 can be configured to diagnose the state of the battery based on a segment in the target capacity segment TR that includes a feature point with the maximum corresponding differential voltage.

[0092] Here, a characteristic point refers to a point included in the target capacity segment TR, and indicates the point with the largest corresponding differential voltage.

[0093] For example, when a feature point is included in the high-capacity segment, the control unit 130 can be configured to diagnose the battery state as a state of available lithium loss. For example, when the shape of the curve has changed to the extent that a feature point exists in the high-capacity segment due to the loss of available lithium in the battery, the control unit 130 can diagnose the battery state as a state of available lithium loss.

[0094] In another example, when the feature point is included in the low-capacity segment, the control unit 130 can diagnose the battery state as one where available lithium has not been lost. Here, as available lithium is lost, the feature point gradually moves towards the high-capacity side, and therefore, even if the feature point is included in the low-capacity segment, the battery's available lithium may be partially lost. According to one embodiment, even if available lithium is partially lost compared to the initial state, the control unit 130 can diagnose the battery state while ignoring the degree of available lithium loss that does not change the shape of the curve.

[0095] For example, in Figure 6 In one embodiment, the feature point is included in the low-capacity segment LQ during the initial cycling (i1) and in the high-capacity segment HQ during the 60th and 90th cycles. In this way, as cycling progresses, the highest differential voltage in the low-capacity segment LQ decreases, and the highest differential voltage in the high-capacity segment HQ increases. As a result, the shape of the curve itself may change due to the loss of available lithium. Therefore, according to one embodiment, the control unit 130 can diagnose whether the battery's available lithium has been lost based on the segment including the feature point.

[0096] The target capacity range TR primarily represents the capacity of the battery's negative electrode. Therefore, the shape of the curve may change most drastically within the target capacity range TR as the battery's available lithium is lost. For example, the location of the characteristic point with the maximum differential voltage within the target capacity range TR changes most significantly.

[0097] For example, in the calibration curve CP of a battery at the beginning of its life (BOL) state, the feature point is included in the low-capacity segment of the target capacity segment TR. However, in the calibration curve CP of a battery with a significant loss of available lithium, the feature point is included in the high-capacity segment of the target capacity segment TR. In this way, as available lithium is lost, the feature point moves from the low-capacity segment of the target capacity segment TR to the high-capacity segment. Therefore, the battery diagnostic device 100 can quickly diagnose the state of the battery by taking into account the abnormal behavior of the feature point due to the loss of available lithium in the battery.

[0098] Figure 7 This is a schematic view showing the state of a battery corresponding to a plurality of calibration curves CP of a second battery according to an embodiment of the present disclosure. Figure 7 Several calibration curves (CP) for a second cell exhibiting a loss of positive electrode capacity are shown. For example, Figure 7 This is a view showing multiple calibration curves CP corresponding to the initial cycle ini, the 10th cycle, the 20th cycle, the 30th cycle, the 40th cycle, the 50th cycle, the 60th cycle, the 70th cycle, the 80th cycle, and the 90th cycle.

[0099] and Figure 6 The implementation methods differ, in Figure 7 In this embodiment, even as cycling continues, the feature points included in the target capacity segment TR remain in the low capacity segment LQ. For example, as long as the battery has not lost usable lithium, the curve shape of the target capacity segment TR will not change even if the battery deteriorates due to other reasons (e.g., loss of positive electrode capacity). Therefore, the battery diagnostic device 100 can quickly diagnose whether the battery is in a state of usable lithium loss based on the loss of usable lithium and the abnormal behavior of the feature points.

[0100] Next, an embodiment in which the control unit 130 sets the target capacity segment TR will be described.

[0101] The control unit 130 can be configured to identify the minimum point with the minimum corresponding capacity among the minimum points included in the calibration curve CP as the target peak tp.

[0102] According to one embodiment, the calibration curve CP may include multiple minimum points. The control unit 130 may be configured to determine the minimum point with the smallest corresponding capacity among the multiple minimum points included in the calibration curve CP as the target peak tp.

[0103] For example, in Figure 5 In this embodiment, the calibration curve CP may include a first minimum point p1, a second minimum point p2, a third minimum point p3, and a fourth minimum point p4. Since the capacity corresponding to the first minimum point p1 among the first to fourth minimum points p4 is the smallest, the control unit 130 can determine the first minimum point p1 as the target peak tp.

[0104] The control unit 130 can be configured to set the target capacity segment TR based on the target differential voltage corresponding to the target peak tp.

[0105] According to one embodiment, the control unit 130 can be configured to determine a reference point rp in the calibration curve CP that corresponds to the target differential voltage and is closest to the target peak tp.

[0106] Generally, in the differential curve DP, which represents the relationship between battery capacity and differential voltage, the differential voltage corresponding to the second minimum point p2 is less than the target differential voltage of the target peak tp. Therefore, the reference point rp determined by the control unit 130 can exist between the target peak tp and the second minimum point p2.

[0107] Therefore, the control unit 130 can be configured to set the capacity segment from the target peak tp to the reference point rp as the target capacity segment TR.

[0108] For example, in Figure 5 In this embodiment, the target differential voltage of the target peak tp is dV1. In the calibration curve CP, in addition to the target peak tp, there are six other points with differential voltages of dV1. The control unit 130 can determine the point among these six points that is closest to the target peak tp as the reference point rp. Then, the control unit 130 can set the capacity range from the capacity of the target peak tp to the capacity of the reference point rp as the target capacity range TR.

[0109] When the differential voltage corresponding to the second minimum point p2 is greater than the target differential voltage of the target peak tp, the target capacity range TR may be set too wide. Since the feature point is close to the target peak tp, it may be impossible to accurately determine whether the shape of the curve has changed based on this overly wide target capacity range TR.

[0110] According to one embodiment, the control unit 130 can be configured such that when the differential voltage of the target peak tp is less than the differential voltage of the second minimum point p2, which has a second minimum corresponding capacity among a plurality of minimum points, the differential voltage corresponding to the second minimum point p2 is set as the target differential voltage.

[0111] Then, the control unit 130 can be configured to determine a reference point rp in the calibration curve CP that corresponds to and is closest to the target differential voltage of the second minimum point p2.

[0112] According to one embodiment, the control unit 130 can determine a reference point rp between a first minimum point p1 and a second minimum point p2.

[0113] Finally, the control unit 130 can be configured to set the capacity segment from the reference point rp to the second minimum point p2 as the target capacity segment TR.

[0114] According to one embodiment, the control unit 130 can set a suitable target capacity segment TR based on the capacity of the second minimum point p2 and the reference point rp. Therefore, the state of the battery can be diagnosed based on the capacity segment of the target capacity segment TR that includes the characteristic point.

[0115] For example, with Figure 5 Different implementations exist where, when the differential voltage of the target peak tp is lower than the differential voltage of the second minimum point p2, the target capacity range TR may be set too wide. In this case, due to... Figure 5The feature points included in the target capacity segment TR in the embodiments may also change, so the state of the battery may be diagnosed inaccurately. An advantage of the battery diagnostic apparatus 100 according to an embodiment of this disclosure is that, even in the exceptional case where the differential voltage corresponding to the target peak tp is lower than the differential voltage of the second minimum point p2, the state of the battery can be accurately diagnosed by appropriately setting the target capacity segment TR.

[0116] 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. In this configuration, at least some of the corresponding components of the battery diagnostic device 100 can be implemented by supplementing or adding the functionality of components included in a well-known BMS. For example, the curve acquisition unit 110, curve correction unit 120, control unit 130, and storage unit 140 of the battery diagnostic device 100 can be implemented as components of a BMS.

[0117] Furthermore, the battery diagnostic device 100 according to this disclosure can be disposed in a battery pack. For example, a battery pack according to this disclosure may include the battery diagnostic device 100 described above and one or more individual battery cells. In addition, the battery pack may also include, for example, electronic components (e.g., relays and fuses) and a housing.

[0118] Figure 8 This is a schematic view of a battery pack 10 according to another embodiment of the present disclosure.

[0119] 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.

[0120] 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 in each of the first sensing line SL1 and the second sensing line SL2.

[0121] The measuring unit 12 can be connected to the current measuring unit A via the third sensing line SL3. For example, the current measuring unit A can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 11. The measuring 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 measuring unit 12 can also measure the discharging current of the battery 11 via the third sensing line SL3 to calculate the amount of discharge.

[0122] For example, the curve acquisition unit 110 can receive battery information about the battery's voltage and current from the measurement unit 12. Then, the curve acquisition unit 110 can generate the battery curve BP and the differential curve DP based on this battery information.

[0123] In another example, curve acquisition unit 110 can receive battery curve BP from measurement unit 12. Then, curve acquisition unit 110 can generate differential curve DP based on battery curve BP.

[0124] In yet another example, curve acquisition unit 110 can receive the differential curve DP from measurement unit 12.

[0125] 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. 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 to each other.

[0126] Figure 9 This is a schematic view of a vehicle 900 according to another embodiment of the present disclosure.

[0127] refer to Figure 9 According to one embodiment of this disclosure, a battery pack 910 can be included in a vehicle 900, such as an electric vehicle (EV) or a hybrid vehicle (HV). The battery pack 910 can supply power to a motor via an inverter disposed in the vehicle 900 to drive the vehicle 900. Here, the battery pack 910 may include a battery diagnostic device 100. For example, the vehicle 900 may include a battery diagnostic device 100. In this case, the battery diagnostic device 100 may be an on-board device included in the vehicle 900.

[0128] Figure 10 This is a schematic view illustrating a battery diagnostic method according to another embodiment of the present disclosure.

[0129] refer to Figure 10 The battery diagnostic method may include a curve acquisition step S100, a target determination step S200, a calibration curve generation step S300, a target peak determination step S400, and a battery diagnostic step S500.

[0130] Each step of this battery diagnostic method can be performed by the battery diagnostic device 100.

[0131] The curve acquisition step S100 is a step of acquiring the differential curve DP, which represents the correspondence between the battery capacity and the differential voltage, and can be executed by the curve acquisition unit 110.

[0132] For example, curve acquisition unit 110 can directly receive the differential curve DP of the battery from an external source. For example, curve acquisition unit 110 can acquire the differential curve DP by connecting to an external source via a wired and / or wireless network to receive the differential curve DP.

[0133] In another example, the curve acquisition unit 110 can directly receive the battery curve BP from an external source. The curve acquisition unit 110 can then generate a differential curve DP based on the battery curve BP. According to one embodiment, the curve acquisition unit 110 can be connected to an external source via wired and / or wireless means to receive the battery curve BP and directly generate the differential curve DP based on the received battery curve BP to obtain the differential curve DP.

[0134] In another example, curve acquisition unit 110 can receive battery information regarding the battery's voltage and capacity. Then, curve acquisition unit 110 can generate a battery curve BP based on the received battery information, and can generate a differential curve DP based on the generated battery curve BP. Curve acquisition unit 110 can acquire the differential curve DP by directly generating the differential curve DP based on the battery information.

[0135] The target determination step S200 is the step of determining the target C rate corresponding to the differential curve DP, and can be executed by the curve correction unit 120.

[0136] For example, curve correction unit 120 can receive the differential curve DP and information about the C-rate from curve acquisition unit 110. Then, curve correction unit 120 can determine the C-rate corresponding to the differential curve DP as the target C-rate.

[0137] The correction curve generation step S300 is a step of generating a correction curve CP by correcting the differential curve DP based on the overvoltage curve corresponding to the target C rate, and can be performed by the curve correction unit 120.

[0138] Then, the curve correction unit 120 can be configured to select an overvoltage curve corresponding to the target C rate from a plurality of pre-stored overvoltage curves. The curve correction unit 120 can be configured to calculate the difference between the differential curve DP and the overvoltage curve to generate a correction curve CP.

[0139] For example, curve correction unit 120 can calculate the differential capacity difference for each voltage between the differential curve DP and the overvoltage curve to generate correction curve CP.

[0140] The target peak determination step S400 is to determine the minimum point with the minimum corresponding capacity among the minimum points included in the calibration curve CP as the target peak tp and to set the target capacity segment TR based on the target differential voltage corresponding to the target peak tp, and can be executed by the control unit 130.

[0141] For example, control unit 130 can be configured to identify the minimum point with the smallest corresponding capacity among a plurality of minimum points included in the calibration curve CP as the target peak tp. Figure 5 In this embodiment, the calibration curve CP may include a first minimum point p1, a second minimum point p2, a third minimum point p3, and a fourth minimum point p4. Since the capacity corresponding to the first minimum point p1 is the smallest among the first to fourth minimum points p4, the control unit 130 can determine the first minimum point p1 as the target peak tp. Furthermore, the control unit 130 can be configured to set the target capacity segment TR based on the target differential voltage corresponding to the target peak tp.

[0142] The battery diagnostic step S500 is a step to diagnose the state of the battery based on the shape of the target capacity segment TR of the calibration curve CP, and can be executed by the control unit 130.

[0143] The control unit 130 can diagnose the battery's state based on whether the shape of the target capacity segment TR has changed. For example, the control unit 130 can determine whether the shape of the target capacity segment TR has changed and diagnose the battery's state based on the determination result.

[0144] For example, control unit 130 can diagnose whether the battery's available lithium has been lost. For example, when it is determined that the shape of the target capacity segment TR has changed, control unit 130 can diagnose the battery's state as a state of available lithium loss.

[0145] The embodiments of this disclosure described above can be implemented not only by apparatus and methods, but also by a program that implements functions corresponding to the components of the embodiments of this disclosure, or a recording medium storing the program. Based on the above description of the embodiments, those skilled in the art to which this disclosure pertains can readily implement such embodiments.

[0146] Although this disclosure has been described with limited embodiments and drawings, it is not limited thereto, and it will be appreciated that various modifications and alterations can be made by those skilled in the art within the scope of the technical concept and equivalents of the appended claims.

[0147] 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-described disclosure is not limited to the foregoing embodiments and drawings, but can selectively combine all or part of these embodiments to achieve various modifications.

[0148] Explanation of reference numerals in the attached figures

[0149] 10: Battery Pack

[0150] 11: Battery

[0151] 12: Measurement Unit

[0152] 100: Battery diagnostic device

[0153] 110: Curve Acquisition Unit

[0154] 120: Curve Correction Unit

[0155] 130: Control Unit

[0156] 140: Storage unit

[0157] 900: Vehicles

[0158] 910: Battery Pack

Claims

1. A battery diagnostic device, comprising: A curve acquisition unit is configured to acquire a differential curve representing the relationship between the battery capacity and the differential voltage. A curve correction unit is configured to determine a target C-rate corresponding to the differential curve and to correct the differential curve based on an overvoltage curve corresponding to the target C-rate, thereby generating a correction curve. as well as A control unit configured to diagnose the state of the battery based on the shape of the target capacity segment of the calibration curve.

2. The battery diagnostic device according to claim 1, wherein, The control unit is configured to determine the minimum point with the minimum corresponding capacity among the multiple minimum points included in the calibration curve as the target peak, and to set the target capacity range based on the target differential voltage corresponding to the target peak.

3. The battery diagnostic device according to claim 2, wherein, The control unit is configured to determine a reference point in the calibration curve that corresponds to the target differential voltage and is closest to the target peak, and to set the capacity range from the target peak to the reference point as the target capacity range (TR).

4. The battery diagnostic device according to claim 2, wherein, The control unit is configured such that when the differential capacity of the target peak is less than the differential capacity of the second minimum point among the plurality of minimum points having a second minimum corresponding capacity, the differential voltage corresponding to the second minimum point is set as the target differential voltage.

5. The battery diagnostic device according to claim 4, wherein, The control unit is configured to determine a reference point in the calibration curve that corresponds to the target differential voltage and is closest to the second minimum point, and to set the capacity range from the reference point to the second minimum point as the target capacity range.

6. The battery diagnostic device according to claim 1, wherein, The control unit is configured to divide the target capacity segment into a low-capacity segment and a high-capacity segment, and to diagnose the state of the battery based on a segment within the target capacity segment that includes a feature point with the maximum corresponding differential voltage.

7. The battery diagnostic device according to claim 6, wherein, The control unit is configured to diagnose the state of the battery as a state of available lithium loss when the feature point is included in the high-capacity segment.

8. The battery diagnostic device according to claim 1, wherein, The curve correction unit is configured to calculate the difference between the differential curve and the overvoltage curve to generate the correction curve.

9. The battery diagnostic device according to claim 1, wherein, The overvoltage curves are pre-stored for each of the multiple C-rates, and The curve correction unit is configured to select an overvoltage curve corresponding to the target C rate from a plurality of pre-stored overvoltage curves.

10. The battery diagnostic device according to claim 1, wherein, The overvoltage curve is preset based on the reference differential curve of the reference battery with respect to the reference C rate and the target differential curve of the reference battery with respect to the target C rate.

11. The battery diagnostic device according to claim 10, wherein, The overvoltage curve is preset to represent the difference between the reference differential curve and the target differential curve.

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

13. A vehicle comprising a battery diagnostic device according to any one of claims 1 to 11.

14. A battery diagnostic method, comprising: The curve acquisition step involves acquiring a differential curve that represents the relationship between the battery's capacity and the differential voltage. The target determination step determines the target C rate corresponding to the differential curve; A correction curve generation step, wherein the correction curve generation step corrects the differential curve based on an overvoltage curve corresponding to the target C-rate to generate a correction curve; and A battery diagnostic step, wherein the battery diagnostic step diagnoses the state of the battery based on the shape of the target capacity segment of the calibration curve.

15. A non-transitory computer-readable storage medium storing a program for performing a battery diagnostic method, the battery diagnostic method comprising: The curve acquisition step involves acquiring a differential curve that represents the relationship between the battery's capacity and the differential voltage. The target determination step determines the target C rate corresponding to the differential curve; A correction curve generation step, wherein the correction curve generation step corrects the differential curve based on an overvoltage curve corresponding to the target C-rate to generate a correction curve; and A battery diagnostic step, wherein the battery diagnostic step diagnoses the state of the battery based on the shape of the target capacity segment of the calibration curve.

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