Battery diagnosis apparatus and battery diagnosis method

Abstract

A battery diagnosis apparatus according to one embodiment of the present invention may comprise: a profile acquisition unit for acquiring a profile representing a correspondence relationship between a plurality of SOC sections of a battery and voltage change values of the respective SOC sections; and a control unit which determines a target SOC on the basis of the results of comparing, in each of the plurality of SOC sections, the voltage change value to a preset criterion change value, and which diagnoses the state of the battery on the basis of the results of comparing the target SOC to a preset criterion SOC.

Description

Battery diagnostic device and method

[0001] The present invention relates to a battery diagnostic device and method.

[0002] This application claims priority to Korean Application No. 10-2024-0071643, filed May 31, 2024, the entire disclosure of which is incorporated herein by reference.

[0003]

[0004] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research into high-performance batteries capable of repeated charging and discharging is actively being conducted.

[0005] Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are receiving attention for their advantages of being able to charge and discharge freely, having a very low self-discharge rate, and having a high energy density, as they have almost no memory effect compared to nickel-based batteries.

[0006] While extensive research is being conducted on these batteries to improve capacity and density, improving lifespan and safety is also crucial. To improve battery safety, technology is required to accurately diagnose the current battery condition.

[0007] Batteries gradually deteriorate with repeated charging and discharging, and changes in cell balance are one cause of battery deterioration. A change in cell balance refers to a phenomenon in which the anode and cathode potentials at the start of a battery's charge or discharge cycle differ from the cathode potential at the beginning of its life (BOL). Furthermore, one cause of this change in cell balance is the loss of available lithium ions due to repeated battery use.

[0008] Changes in cell balance can cause safety and capacity issues for batteries. For example, increases in anode potential can lead to structural collapse of the anode and side reactions with the electrolyte. Furthermore, increases in cathode potential can lead to reduced end-of-charge capacity. Therefore, to ensure safe battery use and maintain high capacity retention, it is necessary to diagnose the battery's condition in relation to changes in cell balance.

[0009]

[0010] The present invention has been devised to solve the above problems, and its purpose is to provide a battery diagnosis device and method for diagnosing the state of a battery related to changes in cell balance.

[0011] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0012]

[0013] A battery diagnostic device according to one aspect of the present invention may include a profile acquisition unit configured to acquire a profile indicating a correspondence between a plurality of SOC sections of a battery and voltage change values ​​of each SOC section; and a control unit configured to determine a target SOC based on a result of comparing the voltage change value and a preset reference change value in each of the plurality of SOC sections, and to diagnose a state of the battery based on a result of comparing the target SOC and the preset reference SOC.

[0014] The control unit may be configured to diagnose the state of the battery as normal if the target SOC is higher than the reference SOC, and to diagnose the state of the battery as abnormal if the target SOC is lower than the reference SOC.

[0015] The above profile may be a profile configured to indicate a correspondence between a plurality of SOC sections divided for each of the plurality of SOCs and a voltage change value of each SOC section.

[0016] The control unit may be configured to determine a target section among the plurality of SOC sections in which the voltage change value exceeds the reference change value, calculate a section value of the determined target section, and determine the calculated section value as the target SOC.

[0017] The above control unit may be configured to determine, when there are multiple determined target intervals, the maximum value among the multiple calculated interval values ​​as the target SOC.

[0018] The above reference SOC may be an SOC determined as one of one or more target SOCs calculated at a previous diagnosis point in time.

[0019] The above reference SOC can be determined as the minimum value among one or more target SOCs.

[0020] A battery pack according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0021] A vehicle according to another aspect of the present invention may include a battery diagnostic device according to one aspect of the present invention.

[0022] A battery management method according to another aspect of the present invention may include a profile acquisition step of acquiring a profile indicating a correspondence between a plurality of SOC sections of a battery and voltage change values ​​of each SOC section; a target SOC determination step of determining a target SOC based on a result of comparing the voltage change value and a preset reference change value in each of the plurality of SOC sections; a comparison step of comparing the target SOC and the preset reference SOC; and a diagnosis step of diagnosing a state of the battery based on a comparison result of the comparison step.

[0023]

[0024] According to one aspect of the present invention, the state of a battery related to a change in cell balance can be diagnosed based on a change in a target SOC section according to an increase in charge / discharge cycles of the battery.

[0025] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0026]

[0027] The following drawings attached to this specification serve to further understand the technical idea of ​​the present invention together with the detailed description of the invention described below, and therefore the present invention should not be interpreted as being limited to the matters described in such drawings.

[0028] FIG. 1 is a schematic diagram illustrating a battery diagnostic device according to one embodiment of the present invention.

[0029] FIG. 2 is a drawing schematically illustrating a profile according to one embodiment of the present invention.

[0030] FIG. 3 is a schematic diagram illustrating a plurality of profiles according to one embodiment of the present invention.

[0031] FIG. 4 is a drawing illustrating an exemplary configuration of a battery pack including a battery diagnostic device according to one embodiment of the present invention.

[0032] FIG. 5 is a schematic drawing of a vehicle according to another embodiment of the present invention.

[0033] FIG. 6 is a schematic diagram illustrating a battery diagnosis method according to another embodiment of the present invention.

[0034]

[0035] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0036] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0037] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0038] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0039] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0040] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

[0041] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0042] FIG. 1 is a schematic diagram illustrating a battery diagnostic device (100) according to one embodiment of the present invention.

[0043] Referring to FIG. 1, the battery diagnostic device (100) may include a profile acquisition unit (110) and a control unit (120). The battery diagnostic device (100) may further include a storage unit (130).

[0044] A battery diagnostic device (100) is provided to diagnose the status of a battery. Depending on the embodiment, the battery diagnostic device (100) may be configured to organically link with other components or modules / devices to generate and output diagnostic data for the battery.

[0045] Here, a battery refers to a physically separate, independent cell having a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery may be considered a battery. Furthermore, the battery may be of a cylindrical type, a prismatic type, or a pouch type. Furthermore, a battery may also refer to a battery bank, a battery module, or a battery pack in which multiple cells are connected in series and / or parallel. For convenience of explanation, the term "battery" will be described herein below as referring to a single, independent cell.

[0046] The profile acquisition unit (110) can be configured to acquire a profile indicating a correspondence between multiple SOC sections of the battery and voltage change values ​​of each SOC section.

[0047] FIG. 2 is a drawing schematically illustrating a profile (P) according to one embodiment of the present invention.

[0048] In the embodiment of FIG. 2, the horizontal axis (X-axis) represents SOC (State of Charge, %), and the vertical axis (Y-axis) represents voltage change value (%). In addition, in FIG. 2, for convenience of explanation, multiple points representing the correspondence between multiple SOC sections and voltage change values ​​are all drawn to be connected.

[0049] Specifically, the profile (P) is a profile that represents the correspondence between multiple SOC sections divided into multiple SOCs and the voltage change values ​​of each SOC section.

[0050] The entire SOC range of the battery can be divided into multiple SOC ranges according to certain conditions.

[0051] In one embodiment, the entire SOC interval may be divided into multiple SOC intervals at regular intervals.

[0052] FIG. 2 is a diagram illustrating an embodiment in which the entire SOC section (SOC 0% to SOC 100%) is divided into 10 SOC sections with regular intervals of 10%. That is, the entire SOC section can be divided into a SOC 0~10% section, a SOC 10~20% section, a SOC 20~30% section, a SOC 30~40% section, a SOC 40~50% section, a SOC 50~60% section, a SOC 60~70% section, a SOC 70~80% section, a SOC 80~90% section, and a SOC 90~100% section.

[0053] In another embodiment, the entire SOC range can be divided into multiple SOC ranges such that the size of each SOC range decreases as the SOC increases. In this case, since the size of the SOC range is relatively small for high SOC ranges, more precise diagnosis is possible for batteries with low voltage fluctuations in high SOC ranges.

[0054] For example, the entire SOC section can be divided into the SOC 0~50% section, the SOC 50~75% section, the SOC 75~85% section, the SOC 85~90% section, the SOC 90~94% section, the SOC 94~97% section, the SOC 97~99% section, and the SOC 99~100% section.

[0055] In another embodiment, the entire SOC range can be divided into multiple SOC ranges such that the size of each SOC range increases as the SOC increases. In this case, since the size of the SOC range is relatively small for low SOC ranges, more precise diagnosis is possible for batteries with low voltage fluctuations in low SOC ranges.

[0056] For example, the entire SOC range can be divided into the SOC 0-3% range, the SOC 3-8% range, the SOC 8-18% range, the SOC 18-40% range, the SOC 40-60% range, and the SOC 60-100% range.

[0057] The voltage change value can be calculated based on the voltage difference between the voltage corresponding to the upper limit SOC and the voltage corresponding to the lower limit SOC of the corresponding SOC section.

[0058] For example, the voltage difference obtained by subtracting the voltage corresponding to the lower limit SOC from the voltage corresponding to the upper limit SOC of the corresponding SOC section can be calculated as a voltage change value.

[0059] As another example, a voltage change value may be calculated based on the difference between the voltage difference and a preset initial voltage difference. Here, the initial voltage difference may refer to a voltage difference obtained when the battery is in a BOL state. In addition, the initial voltage difference may be preset to correspond to each of a plurality of SOC sections. Specifically, a voltage difference between a voltage corresponding to an upper limit SOC and a voltage corresponding to a lower limit SOC of the corresponding SOC section may be calculated. In addition, a value obtained by dividing the difference between the calculated voltage difference and the initial voltage difference by the initial voltage difference may be calculated as a voltage change value.

[0060] In the embodiment of Fig. 2, the voltage change value was calculated by dividing the difference between the voltage difference (upper limit voltage - lower limit voltage) in the corresponding SOC section and the initial voltage difference by the initial voltage difference. That is, the voltage change value for the corresponding SOC section can be calculated according to the formula "{(upper limit voltage - lower limit voltage) - initial voltage difference} ÷ initial voltage difference × 100".

[0061] Meanwhile, Fig. 2 is a diagram illustrating the voltage change values ​​of each SOC section in relation to the upper limit value of the corresponding SOC section. For example, the voltage change values ​​of the SOC 0-10% section are illustrated in relation to SOC 10%. Therefore, it can be confirmed that the SOC at the point marked with "■" in Fig. 2 is the upper limit value of multiple SOC sections.

[0062] In this specification, acquisition of any data or information should be understood to mean reception from an external source through a communication means, input from a user through an input means, or creation through execution of a program, etc.

[0063] For example, the profile acquisition unit (110) can receive a profile from the outside. That is, the profile acquisition unit (110) can receive a profile by being connected to the outside through a wired and / or wireless connection. For example, the profile acquisition unit (110) can receive a profile from the outside through a wired communication method such as CAN (Controller Area Network) communication or CAN-FD (CAN with Flexible Data rate) communication. As another example, the profile acquisition unit (110) can receive a profile from the outside through a wireless communication method such as Zigbee, Bluetooth, Wi-Fi, WFD (Wi-Fi Direct), UWB (Ultra-wideband), or mobile communication. Of course, as long as it supports communication between the profile acquisition unit (110) and the outside, the type of communication protocol is not particularly limited.

[0064] As another example, the profile acquisition unit (110) can receive battery information regarding the voltage and current of the battery. Furthermore, the profile acquisition unit (110) can generate a profile based on the received battery information.

[0065] Specifically, the profile acquisition unit (110) can estimate the SOC based on the received battery information. The SOC can be calculated through various techniques such as current integration, equivalent circuit model, and Kalman filter. The profile acquisition unit (110) can determine multiple SOC sections based on the estimated SOC and calculate voltage change values ​​corresponding to each SOC section. In addition, the profile acquisition unit (110) can generate a profile by recording the multiple SOC sections and the multiple voltage change values ​​in association with each other.

[0066] FIG. 3 is a schematic diagram illustrating a plurality of profiles (P0, P1, P2, P3) according to one embodiment of the present invention. The initial profile (P0) and the first to third profiles (P1, P2, P3) are profiles obtained by repeatedly charging and discharging the same battery. In addition, the initial profile (P0) and the first to third profiles (P1, P2, P3) are profiles obtained in different charge and discharge cycles. The initial profile (P0) is a profile obtained when the battery is in a BOL state. The first profile (P1) is a profile obtained when the charge and discharge cycle of the battery is 200 cycles (corresponding to the first diagnosis time point). The second profile (P2) is a profile obtained when the charge and discharge cycle of the battery is 400 cycles (corresponding to the second diagnosis time point). The third profile (P3) is a profile obtained when the charge and discharge cycle of the battery is 600 cycles (corresponding to the third diagnosis time point). Meanwhile, the third profile (P3) according to the embodiment of FIG. 3 may be the same profile as the profile (P) according to the embodiment of FIG. 2.

[0067] The control unit (120) may be configured to determine a target SOC based on the results of comparing the voltage change value and the preset reference change value in each of a plurality of SOC sections. That is, the control unit (120) may determine one target SOC for one profile.

[0068] The reference change value can be preset for each of the multiple SOC intervals. For example, the reference change value can be preset based on the reference profile acquired at a previous diagnosis time point. Preferably, if there are multiple previous diagnosis time points, the reference change value can be preset based on the reference profile acquired at the most recent diagnosis time point among the previous diagnosis time points. Additionally, the reference change value can be preset to correspond to the voltage change value. That is, the reference change value can be preset to a value calculated in the same manner as the voltage change value.

[0069] Specifically, the reference change value can be preset based on the voltage difference between the voltage corresponding to the upper limit SOC and the voltage corresponding to the lower limit SOC of multiple SOC sections.

[0070] For example, the voltage difference obtained by subtracting the voltage corresponding to the lower limit SOC from the voltage corresponding to the upper limit SOC of the corresponding SOC section can be preset as a reference change value.

[0071] As another example, a reference change value may be preset based on the difference between the voltage difference and a preset initial voltage difference. Here, the initial voltage difference may refer to a voltage difference obtained when the battery is in a BOL state. In addition, the initial voltage difference may be preset to correspond to each of a plurality of SOC sections. Specifically, a value obtained by dividing the difference between the voltage difference corresponding to the upper limit SOC and the voltage corresponding to the lower limit SOC of the corresponding SOC section and the initial voltage difference by the initial voltage difference may be preset as the reference change value.

[0072] If no previous diagnostic point exists, the reference SOC corresponding to each of the multiple SOC intervals can all be preset to 0. That is, the initial value of the reference SOC can be preset to 0.

[0073] The control unit (120) can compare the voltage change value in each of the plurality of SOC sections with a reference change value. Specifically, the control unit (120) can compare the magnitude of the voltage change value in each SOC section with the reference change value.

[0074] For example, the control unit (120) can compare the voltage change value corresponding to the SOC 90-100% section at the diagnosis time with the voltage change value corresponding to the SOC 90-100% section at the previous diagnosis time (i.e., the reference change value).

[0075] The control unit (120) can be configured to determine a target section among multiple SOC sections in which the voltage change value exceeds a reference change value.

[0076] Specifically, the control unit (120) can compare the voltage change value corresponding to each of the plurality of SOC sections with the reference change value. For example, the control unit (120) can compare the magnitude of the voltage change value corresponding to each of the plurality of SOC sections with the reference change value. The control unit (120) can determine the SOC section in which the voltage change value exceeds the reference change value as the target section.

[0077] In the embodiment of FIG. 3, the voltage change value may be determined based on the third profile (P3). In this case, the reference change value may be preset based on the second profile (P2). That is, the voltage change value may be determined based on the third profile (P3) acquired at the third diagnostic time point. In addition, the reference change value may be determined based on the second profile (P2) acquired at the second diagnostic time point. That is, the voltage change value may be determined based on the profile at the nth diagnostic time point, and the reference change value may be determined based on the profile at the (n-1)th diagnostic time point.

[0078] The control unit (120) can compare the voltage change value in each SOC section with the reference change value.

[0079] Specifically, the control unit (120) can compare the magnitude between the voltage change value in each SOC section and the reference change value.

[0080] Referring to FIG. 3, the SOC sections in which the voltage change value exceeds the reference change value are the SOC 40-50% section, the SOC 50-60% section, the SOC 60-70% section, the SOC 70-80% section, and the SOC 80-90% section. Accordingly, the control unit (120) can determine the SOC 40-50% section, the SOC 50-60% section, the SOC 60-70% section, the SOC 70-80% section, and the SOC 80-90% section as target sections.

[0081] The control unit (120) can be configured to calculate the interval value of the determined target interval.

[0082] Here, the interval value is a value representing the corresponding target interval and can be calculated based on multiple SOCs included in the target interval. For example, the interval value can be calculated as the maximum value, minimum value, average value, or median value of the target interval. Meanwhile, it should be noted that the interval value is not limited to the maximum value, minimum value, average value, or median value as long as it can be calculated in the same manner during the diagnostic process by the battery diagnostic device (100).

[0083] In the embodiment of FIG. 3, the control unit (120) can calculate the maximum value among the SOCs included in the target section as the section value. That is, the control unit (120) can calculate SOC 50%, SOC 60%, SOC 70%, SOC 80%, and SOC 90% as the section values.

[0084] The control unit (120) can be configured to determine the calculated interval value as the target SOC.

[0085] If there are multiple determined target intervals, the control unit (120) can be configured to determine the maximum value among the multiple calculated interval values ​​as the target SOC.

[0086] In the embodiment of FIG. 3, since there are multiple target sections, the control unit (120) can determine the maximum value of the multiple calculated section values, SOC 90%, as the target SOC.

[0087] The control unit (120) may be configured to diagnose the state of the battery based on the result of comparing the target SOC and the preset reference SOC.

[0088] Here, the reference SOC can be preset to one or more target SOCs calculated at a previous diagnosis point.

[0089] If no previous diagnostic point exists, the baseline SOC can represent an initial value. The initial value of the baseline SOC can be preset to the maximum value among the interval values. That is, at the first diagnostic point, the baseline SOC can be preset to the maximum value among the interval values.

[0090] Preferably, the reference SOC can be determined as the minimum value among one or more target SOCs calculated at a previous diagnostic point in time.

[0091] Specifically, if there is only one target SOC calculated at a previous diagnosis point, that target SOC can be determined as the reference SOC. If two or more target SOCs calculated at a previous diagnosis point are all the same, that target SOC can be determined as the reference SOC. Conversely, if two or more target SOCs calculated at a previous diagnosis point are different from each other, the minimum value of the two or more target SOCs can be determined as the reference SOC.

[0092] In the embodiment of FIG. 3, the diagnostic points prior to the third diagnostic point, which is the current diagnostic point, are the first diagnostic point and the second diagnostic point. The reference SOC may be preset as either the target SOC calculated at the first diagnostic point or the target SOC calculated at the second diagnostic point. Preferably, the reference SOC may be determined as the minimum value between the target SOC calculated at the first diagnostic point and the target SOC calculated at the second diagnostic point. As described above, the target SOC at the previous diagnostic point may be set based on the comparison result between the voltage change value corresponding to each SOC section and the initial value of the reference SOC.

[0093] Specifically, when comparing the first profile (P1) with the initial profile (P0), the SOC 0~10% section, the SOC 10~20% section, the SOC 20~30% section, the SOC 30~40% section, and the SOC 90~100% section can be determined as target sections, and SOC 10%, SOC 20%, SOC 30%, SOC 40%, and SOC 100% can be determined as section values. In addition, among the determined multiple section values, the maximum value of SOC 100% can be determined as the target SOC at the first diagnosis time point.

[0094] Next, when comparing the second profile (P2) with the first profile (P1), the SOC 0-10% section, the SOC 10-20% section, the SOC 20-30% section, and the SOC 90-100% section can be determined as target sections, and SOC 10%, SOC 20%, SOC 30%, and SOC 100% can be determined as section values. In addition, the maximum value of the determined multiple section values, SOC 100%, can be determined as the target SOC at the second diagnosis time point.

[0095] Therefore, since the target SOC calculated at the diagnostic time points (the first diagnostic time point and the second diagnostic time point) prior to the third diagnostic time point is the same as SOC 100%, the reference SOC can be preset as SOC 100%.

[0096] The control unit (120) can diagnose the state of the battery related to cell balance as abnormal or normal based on the result of comparing the size of the target SOC and the reference SOC.

[0097] If the target SOC is greater than or equal to the reference SOC, the control unit (120) may be configured to diagnose the battery's condition as normal. Conversely, if the target SOC is less than the reference SOC, the control unit (120) may be configured to diagnose the battery's condition as abnormal.

[0098] In the embodiment of FIG. 3, since the target SOC (90%) at the third diagnostic point is less than the reference SOC (100%), the control unit (120) can diagnose the state of the battery as abnormal.

[0099] Here, an abnormal state means a state in which the battery is degraded and the cell balance is different compared to when it is in the BOL state. A change in the cell balance means a case in which the starting potential of the positive and negative electrodes for charging or discharging is different from the potentials of the positive and negative electrodes in the BOL state. Specifically, if the potential of the positive electrode at the start of charging or discharging is different from the potential of the positive electrode in the BOL state, it can be determined that the cell balance has changed. Alternatively, if the potential of the negative electrode at the start of charging or discharging is different from the potential of the negative electrode in the BOL state, it can be determined that the cell balance has changed. Alternatively, if the potential of the positive electrode and the potential of the negative electrode at the start of charging or discharging are different from the potential of the positive electrode and the potential of the negative electrode in the BOL state, it can be determined that the cell balance has changed.

[0100] If the battery's charge / discharge voltage range remains constant, changes in both the positive and negative electrode potentials occur simultaneously. Here, the charge / discharge voltage range includes a charge upper limit voltage and a discharge lower limit voltage. The charge upper limit voltage is a preset voltage at which battery charging is terminated and can be preset based on battery characteristics. The discharge lower limit voltage is a preset voltage at which battery discharge is terminated and can be preset based on battery characteristics.

[0101] For example, let's assume that the lower discharge limit voltage of a battery is preset to 2.5 V, and in the BOL state, the anode potential is 3.0 V and the cathode potential is 0.5 V. If the battery degrades and the anode potential increases to 3.2 V, the cathode potential may also increase to 0.7 V. This is because the potential difference between the anode and cathode potentials (3.2-0.7 V) remains at 2.5 V. Similarly, if the cathode potential increases to 0.7 V, the anode potential can also be expressed as increasing to 3.2 V.

[0102] Changes in cell balance can cause safety and capacity issues for the battery. For example, increases in anode potential can lead to structural collapse of the anode and side reactions with the electrolyte. Furthermore, increases in cathode potential can lead to reduced end-of-charge capacity. Therefore, to ensure safe battery use and maintain high capacity retention, it is necessary to diagnose the battery's condition in relation to changes in cell balance.

[0103] The inventor of the present application recognized that as the cell balance of a battery changes, the target SOC section shows a tendency to move toward a low SOC. That is, the inventor of the present application recognized that when comparing the voltage change value and the reference change value for each SOC section, the target SOC section in which the voltage change value exceeds the reference change value shows a tendency to move toward a low SOC as the battery deteriorates. Therefore, according to one embodiment of the present invention, if the change pattern of the target SOC section according to an increase in the charge / discharge cycle of the battery is identified, the state of the battery related to the change in cell balance can be diagnosed.

[0104] Meanwhile, the control unit (120) provided in the battery diagnostic device (100) may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc. known in the art to execute various control logics performed in the present invention. In addition, when the control logic is implemented in software, the control unit (120) may be implemented as a set of program modules. At this time, the program modules may be stored in a memory and executed by the control unit (120). The memory may be located inside or outside the control unit (120) and may be connected to the control unit (120) by various well-known means.

[0105] In addition, the battery diagnostic device (100) may further 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 in the process of performing operations and functions. The storage unit (130) is not particularly limited in type as long as it is a known information storage means known to be capable of recording, erasing, updating, and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. In addition, the storage unit (130) may store program codes defining processes executable by the control unit (120).

[0106] Specifically, the storage unit (130) can store information necessary for the control unit (120) to diagnose the status of the battery. For example, the storage unit (130) can store a profile, an initial voltage difference, a reference change value, a reference SOC, etc. In addition, the control unit (120) can access the storage unit (130) to obtain information necessary for diagnosing the status of the battery. For example, a profile obtained by the profile obtaining unit (110) is stored in the storage unit (130), and the control unit (120) can access the storage unit (130) to obtain the stored profile.

[0107] The battery diagnosis device (100) according to the present invention can be applied to a BMS (Battery Management System). That is, the BMS according to the present invention can include the battery diagnosis device (100) described above. In this configuration, at least some of the components of the battery diagnosis device (100) can be implemented by supplementing or adding to the functions of the components included in a conventional BMS. For example, the profile acquisition unit (110), the control unit (120), and the storage unit (130) of the battery diagnosis device (100) can be implemented as components of the BMS.

[0108] In addition, the battery diagnostic device (100) according to the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the battery diagnostic device (100) described above and one or more battery cells. In addition, the battery pack may further include electrical components (relays, fuses, etc.) and a case, etc.

[0109] FIG. 4 is a drawing illustrating an exemplary configuration of a battery pack (10) including a battery diagnostic device (100) according to one embodiment of the present invention.

[0110] The positive terminal of the battery (11) can be connected to the positive terminal (P+) of the battery pack (10), and the negative terminal of the battery (11) can be connected to the negative terminal (P-) of the battery pack (10).

[0111] The measuring unit (12) can be connected to a first sensing line (SL1), a second sensing line (SL2), and a third sensing line (SL3). Specifically, the measuring unit (12) can be connected to a positive terminal of the battery (11) through the first sensing line (SL1), and can be connected to a negative terminal of the battery (11) through 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).

[0112] And, the measuring unit (12) can be connected to the current measuring unit (A) through 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) through the third sensing line (SL3) to calculate the charging amount. In addition, the measuring unit (12) can measure the discharging current of the battery (11) through the third sensing line (SL3) to calculate the discharging amount.

[0113] A load (not shown) may have one end connected to the positive terminal (P+) of the battery pack (10) and the other end connected to the negative terminal (P-) of the battery pack (10). Accordingly, the positive terminal of the battery (11), the positive terminal (P+) of the battery pack (10), the load, the negative terminal (P-) of the battery pack (10), and the negative terminal of the battery (11) may be electrically connected.

[0114] For example, the load may be a charging device that supplies power to a battery (11), or may be a motor of an electric vehicle that receives power from the battery (11).

[0115] FIG. 5 is a schematic drawing of a vehicle (1) according to another embodiment of the present invention.

[0116] Referring to FIG. 5, a battery pack (10) according to an embodiment of the present invention may be included in a vehicle (1), such as an electric vehicle (EV) or a hybrid vehicle (HV). Here, the battery pack (10) described above may be applied. In addition, the battery pack (10) may drive the vehicle (1) by supplying power to a motor through an inverter provided in the vehicle (1). Here, the battery pack (10) may include a battery diagnostic device (100). That is, the vehicle (1) 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 (1).

[0117] FIG. 6 is a schematic diagram illustrating a battery diagnosis method according to another embodiment of the present invention.

[0118] Referring to FIG. 6, the battery diagnosis method may include a profile acquisition step (S100), a target SOC determination step (S200), a comparison step (S300), and a diagnosis step (S400).

[0119] Preferably, each step of the battery diagnosis method can be performed by the battery diagnosis device (100). In the following, for convenience of explanation, any content that overlaps with the previously described content will be omitted or briefly described.

[0120] The profile acquisition step (S100) is a step of acquiring a profile indicating a correspondence between multiple SOC sections of a battery and voltage change values ​​of each SOC section, and can be performed by a profile acquisition unit (110).

[0121] The target SOC determination step (S200) is a step of determining the target SOC based on the result of comparing the voltage change value and the preset reference change value in each of the plurality of SOC sections, and can be performed by the control unit (120).

[0122] Specifically, the control unit (120) can compare the voltage change value in each of the plurality of SOC sections with a reference change value. Specifically, the control unit (120) can compare the magnitude of the voltage change value in each SOC section with the reference change value.

[0123] The control unit (120) may be configured to determine a target section among multiple SOC sections in which the voltage change value exceeds a reference change value. In addition, the control unit (120) may be configured to calculate a section value of the determined target section and determine the calculated section value as the target SOC.

[0124] The interval value can be calculated based on multiple SOCs included in the target interval. For example, the interval value can be calculated as the maximum value, minimum value, or median value of the target interval. It should be noted that the interval value is not limited to the maximum value, minimum value, or median value as long as it can be calculated in the same manner during the diagnostic process by the battery diagnostic device (100).

[0125] If there are multiple determined target intervals, the control unit (120) can be configured to determine the maximum value among the multiple calculated interval values ​​as the target SOC.

[0126] The comparison step (S300) is a step of comparing the target SOC and a preset reference SOC, and can be performed by the control unit (120).

[0127] Specifically, the control unit (120) can compare the magnitude between the voltage change value in each SOC section and the reference change value.

[0128] The diagnosis step (S400) is a step of diagnosing the status of the battery based on the comparison result of the comparison step, and can be performed by the control unit (120).

[0129] Specifically, the control unit (120) can diagnose the state of the battery related to cell balance as an abnormal state or a normal state based on the result of comparing the size of the target SOC and the reference SOC.

[0130] If the target SOC is greater than or equal to the reference SOC, the control unit (120) may be configured to diagnose the battery's condition as normal. Conversely, if the target SOC is less than the reference SOC, the control unit (120) may be configured to diagnose the battery's condition as abnormal.

[0131] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0132] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0133] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

[0134]

[0135] [Explanation of symbols]

[0136] 1: Car

[0137] 10: Battery pack

[0138] 100: Battery Diagnostic Device

[0139] 110: Profile acquisition section

[0140] 120: Control unit

[0141] 130: Storage

Claims

1. A profile acquisition unit configured to acquire a profile indicating a correspondence between multiple SOC sections of a battery and voltage change values ​​of each SOC section; and A battery diagnostic device including a control unit configured to determine a target SOC based on a result of comparing the voltage change value and a preset reference change value in each of a plurality of SOC sections, and to diagnose the state of the battery based on a result of comparing the target SOC and the preset reference SOC.

2. In paragraph 1, The above control unit, If the target SOC is higher than the reference SOC, the battery status is diagnosed as normal, A battery diagnostic device configured to diagnose the state of the battery as abnormal if the target SOC is less than the reference SOC.

3. In paragraph 1, The above profile is, A battery diagnostic device characterized in that the profile is configured to indicate a correspondence between a plurality of SOC sections divided by the plurality of SOCs and a voltage change value of each SOC section.

4. In paragraph 1, The above control unit, A battery diagnostic device configured to determine a target section in which the voltage change value exceeds the reference change value among the plurality of SOC sections, calculate a section value of the determined target section, and determine the calculated section value as the target SOC.

5. In paragraph 4, The above control unit, A battery diagnostic device configured to determine the maximum value among the multiple calculated range values ​​as the target SOC when there are multiple determined target ranges.

6. In paragraph 1, The above standard SOC is, A battery diagnostic device characterized in that the SOC is determined as one of one or more target SOCs calculated at a previous diagnostic point.

7. In paragraph 6, The above standard SOC is, A battery diagnostic device characterized in that the target SOC is determined as the minimum value among the above one or more target SOCs.

8. A battery pack comprising a battery diagnostic device according to any one of claims 1 to 7.

9. A vehicle including a battery diagnostic device according to any one of paragraphs 1 to 7.

10. A profile acquisition step for acquiring a profile representing the correspondence between multiple SOC sections of a battery and the voltage change value of each SOC section; A target SOC determination step for determining a target SOC based on the results of comparing the voltage change value and the preset reference change value in each of a plurality of SOC sections; A comparison step for comparing the target SOC and the preset reference SOC; and A battery diagnosis method including a diagnosis step of diagnosing the state of the battery based on the comparison result of the above comparison step.

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