Battery diagnosis device and method

Abstract

A battery diagnosis device according to one embodiment of the present invention is a device for diagnosing a state of a battery pack including a plurality of cells, and may include: at least one processor; and a memory for storing at least one command executed by the at least one processor, where the at least one command may include the following commands: checking whether the battery pack enters a sleep state after being fully charged; measuring a first voltage after a first time elapses after entering the sleep state; measuring a second voltage after a second time elapses after entering the sleep state; calculating a self-discharge amount of the battery pack based on the first voltage and the second voltage; and determining a state of the battery pack by comparing a self-discharge amount of the battery pack with a preset critical discharge current amount.

Description

Technical Field

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2023-0160137, filed with the Korean Intellectual Property Office on November 20, 2023, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to battery diagnostic apparatus and methods, and more specifically, to battery diagnostic apparatus and methods for diagnosing short circuits in a battery using the self-discharge of the battery. Background Technology

[0003] Rechargeable and reusable secondary batteries can be used as power sources for small devices such as mobile phones, tablets, and vacuum cleaners, as well as for medium and large devices such as personal mobility devices, automobiles, and energy storage systems (ESS) for smart grids.

[0004] Depending on system requirements, secondary batteries can be used in the system in the form of components (such as battery modules or battery packs in which multiple battery cells are connected in series and parallel, or battery racks in which battery modules or battery packs are connected in series and parallel).

[0005] Rechargeable batteries are manufactured to prevent short circuits by preventing contact between the positive and negative electrodes via a porous insulating membrane (separator). However, during battery manufacturing, insulation may not be properly maintained for various reasons, potentially causing an internal short circuit within the battery. If a short circuit occurs between the positive and negative electrodes of a lithium-ion battery, it can lead to fire or explosion. Even with a very small short circuit, ions move and current flows; this condition is often referred to as a soft short circuit or micro-short circuit. If deposits form due to a soft short circuit, low-voltage failure may occur.

[0006] During the manufacturing process, battery cells may undergo stability tests, such as overcurrent testing, high-temperature storage testing, short-circuit testing, and penetration testing, to assess battery safety due to defects or failures that may occur during battery operation. However, even batteries that have passed these stability tests and have been shipped may still retain defects that were not detected during shipping testing, or may experience problems such as low current and short circuits during battery use due to factors such as the operating environment, which could pose a risk to the safety of the battery pack. Summary of the Invention

[0007] Technical issues

[0008] To eliminate one or more problems in the related technologies, embodiments of this disclosure provide a battery diagnostic device for diagnosing low voltage or short circuit conditions in cells of a battery pack.

[0009] To eliminate one or more problems of the related technologies, embodiments of this disclosure also provide a battery diagnostic method for diagnosing low voltage or short circuit conditions in cells of a battery pack.

[0010] Technical solution

[0011] To achieve the purposes of this disclosure, a battery diagnostic device for diagnosing the state of a battery pack comprising multiple cells may include: at least one processor; and a memory configured to store at least one instruction executed by the at least one processor.

[0012] Here, at least one instruction may include: an instruction for monitoring whether the battery pack has entered a dormant state after being fully charged; an instruction for measuring a first voltage after a first time period has elapsed since entering the dormant state; an instruction for measuring a second voltage after a second time period has elapsed since entering the dormant state; an instruction for calculating the self-discharge of the battery pack based on the first voltage and the second voltage; and an instruction for determining the state of the battery pack by comparing the self-discharge of the battery pack with a predetermined critical discharge current.

[0013] Here, the instructions for calculating the self-discharge of the battery pack may include: instructions for using the state of charge (SOC)-voltage correlation to derive a first SOC that matches a first voltage and a second SOC that matches a second voltage; and instructions for using the difference between the first SOC and the second SOC to calculate the self-discharge.

[0014] The first and second voltages can be obtained by measuring the open-circuit voltage (OCV) of the battery pack.

[0015] Instructions for determining the state of a battery pack may include instructions for determining that an anomaly has occurred in at least one of a plurality of battery cells if the self-discharge of the battery pack is greater than or equal to a predetermined critical discharge current.

[0016] Here, the real-time clock (RTC) within the battery management system (BMS) can be used to determine whether the first time period has elapsed and whether the second time period has elapsed.

[0017] Meanwhile, the critical discharge current can indicate the amount of self-discharge current generated when an internal short circuit occurs in the battery cell, and can be obtained in advance through experiments on battery cells in which an internal short circuit occurs.

[0018] Here, the critical discharge current may include: a first critical discharge current indicating that a permanent failure has occurred in the battery pack; a second critical discharge current indicating that a repairable failure has occurred in the battery pack; and a third critical discharge current indicating that a minor anomaly relative to a repairable failure has occurred in the battery pack.

[0019] According to another embodiment of this disclosure, a battery diagnostic method may include: monitoring whether a battery pack comprising multiple cells has entered a dormant state after being fully charged; measuring a first voltage after a first time period has elapsed since entering the dormant state; measuring a second voltage after a second time period has elapsed since entering the dormant state; calculating the self-discharge of the battery pack based on the first voltage and the second voltage; and determining the state of the battery pack by comparing the self-discharge of the battery pack with a predetermined critical discharge current.

[0020] Calculating the self-discharge of a battery pack may include: using the state of charge (SOC)-voltage correlation to derive a first SOC that matches a first voltage and a second SOC that matches a second voltage; and using the difference between the first SOC and the second SOC to calculate the self-discharge.

[0021] The first and second voltages can be obtained by measuring the open-circuit voltage (OCV) of the battery pack.

[0022] Determining the state of a battery pack may include: determining that an anomaly has occurred in at least one of the multiple battery cells if the self-discharge of the battery pack is greater than or equal to a predetermined critical discharge current.

[0023] Here, the real-time clock (RTC) within the battery management system (BMS) can be used to determine whether the first time period has elapsed and whether the second time period has elapsed.

[0024] Meanwhile, the critical discharge current can indicate the amount of self-discharge current generated when an internal short circuit occurs in the battery cell, and can be obtained in advance through experiments on battery cells in which an internal short circuit occurs.

[0025] Here, the critical discharge current may include: a first critical discharge current indicating that a permanent failure has occurred in the battery pack; a second critical discharge current indicating that a repairable failure has occurred in the battery pack; and a third critical discharge current indicating that a minor anomaly has occurred in the battery pack compared to a repairable failure.

[0026] Beneficial effects

[0027] According to embodiments of this disclosure, abnormalities caused by short circuits in battery cells can be diagnosed within a short timeframe without requiring a long period of battery use.

[0028] Therefore, battery pack safety can be enhanced through more robust battery pack condition diagnostics. Attached Figure Description

[0029] Figure 1 This is a block diagram of a battery system to which embodiments of the present invention can be applied.

[0030] Figure 2 This is a schematic flowchart of a typical method for detecting internal short circuits in a battery system.

[0031] Figure 3 This is an operation flowchart of a battery diagnostic method according to an embodiment of the present invention.

[0032] Figure 4 This is a graph showing the SOC-voltage correlation for calculating self-discharge according to an embodiment of the present invention.

[0033] Figure 5a This is a graph showing the results of a self-discharge current measurement experiment when a short circuit occurs inside the cell. Figure 5b This is a graph showing the results of a voltage measurement experiment when a short circuit occurs inside the cell.

[0034] Figure 6 This is a detailed operation flowchart of battery diagnostics based on self-discharge according to an embodiment of the present invention.

[0035] Figure 7 This is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0036] 100: Battery; 200: Battery diagnostic device

[0037] 210: Processor; 220: Memory

[0038] 230: Communication module; 290: RTC component Detailed Implementation

[0039] This invention can be modified in various forms and has various embodiments, and specific embodiments thereof are illustrated by way of example in the accompanying drawings and will be described in detail below. However, it should be understood that the invention is not intended to be limited to the specific embodiments, but rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and technical scope of the invention. Throughout the description of the accompanying drawings, similar reference numerals refer to similar elements.

[0040] It will be understood that although various elements may be described herein using terms such as first, second, A, B, etc., these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element without departing from the scope of the invention, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes a combination of or any one of the associated listed items.

[0041] What will be understood is that when a component is referred to as "coupled" or "connected" to another component, it can be directly coupled or connected to the other component, or there may be intermediate components. Conversely, when a component is referred to as "directly coupled" or "directly connected" to another component, there are no intermediate components.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are also intended to include the plural forms. It will also be understood that the terms “comprises,” “comprising,” “includes,” “including,” and / or “having” as used herein specify the presence of the stated features, integers, steps, operations, constituent elements, components, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, constituent elements, components, and / or combinations thereof.

[0043] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms such as those defined in commonly used dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0044] The following are definitions of some of the terms used in this article.

[0045] A battery cell is a basic unit used to store electricity, and a battery module is an assembly in which multiple battery cells are electrically connected.

[0046] A battery assembly may include multiple electrically connected battery cells and refers to an assembly used as a power source by application to a particular system or device. Here, a battery assembly may refer to a battery module, battery pack, battery rack, or battery bank, but the scope of the invention is not limited to these entities.

[0047] State of charge (SOC) refers to the current state of a battery, expressed as a percentage [%], while state of health (SOH) can be the current state of a battery compared to its ideal or original condition, expressed as a percentage [%].

[0048] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0049] Figure 1 This is a block diagram of a battery system to which embodiments of the present invention can be applied.

[0050] Reference Figure 1 The battery pack 100 may include multiple battery cells connected in series and parallel. More specifically, the multiple battery cells may be connected in parallel to form a battery bank, and the multiple battery banks may be connected in series to form a battery pack. In other words, the battery pack 100 may be configured to include multiple battery banks containing multiple battery cells connected in parallel. Figure 1 In one embodiment, a battery bank comprises four battery cells connected in parallel. Alternatively, a battery pack may comprise ten battery banks connected in series. However, the number of battery cells constituting a battery bank and the number of battery banks constituting a battery pack are not limited to these specifications. Figure 1 The embodiments presented herein are applicable to battery packs configured with various connection types and various numbers of cells and libraries.

[0051] Additionally, depending on the system in which the battery pack is used, a battery pack can also be referred to as a battery module. Furthermore, a battery pack can be understood as any term referring to a component of battery cells used in a specific system or device and serving as a power source.

[0052] The battery pack can be connected to a load via positive and negative terminals to perform charging / discharging. A battery management system (BMS) 200 can be installed in such a battery pack. In this specification, the battery system is used as a concept comprising one or more battery packs 100 and a battery management system 200. Alternatively, the battery management system 200 can be included within the battery pack 100, and the battery pack can be used in the same / similar sense as the battery system.

[0053] The Battery Management System (BMS) 200 can monitor the current, voltage, and temperature of the battery pack, calculate the state of charge (SOC) based on the monitoring results, and control charging / discharging. Here, the state of charge (SOC) is expressed as the percentage of the battery's current state of charge [%].

[0054] The Battery Management System (BMS) 200 can also balance the charge evenly between battery cells or battery banks to extend the life of the battery system. To perform this operation, the BMS 200 may include various components such as fuses, current sensing elements, thermistors, switches, and balancers.

[0055] Figure 2 This is a schematic flowchart of a typical method for detecting internal short circuits in a battery system.

[0056] Battery management systems can typically detect internal short circuits in cells by detecting voltage and SOC deviations between cells. Figure 2 A typical method for identifying internal short circuits in a cell using the library imbalance diagnostic function of a BMS is shown.

[0057] Reference Figure 2 The BMS measures the voltage of each cell in the battery pack and monitors the voltage deviation between cells (S11). Here, in... Figure 1 In the battery system shown, since the four battery cells in one library are connected in parallel, the voltage of each measured cell is the same as the voltage of the corresponding library. Therefore, in such a system... Figure 1 In the battery system shown, the voltage deviation between cells can be used with the same meaning as the voltage deviation between batteries. The voltage deviation between cells can be measured separately when the battery is charging, discharging, and in a dormant state.

[0058] The measured inter-unit voltage deviation is compared with the critical voltage deviation ( The voltage deviation between cells is compared (S12), and if the voltage deviation between cells is equal to or greater than the critical voltage deviation, a defect is determined to have occurred in the battery (S16), and a warning signal is generated. Here, the critical voltage deviation ( The voltage can be set to, for example, 100 mV. In response to the generated warning signal, the BMS can control the charging field-effect transistor (FET) or the discharging FET to operate in the corresponding mode.

[0059] The BMS monitors the voltage deviation between cells and the SOC of each library, and compares the SOC of each library (S13). The SOC deviation between libraries is compared with the critical SOC deviation. Compare (S14). If the SOC deviation between the libraries is greater than or equal to the critical SOC deviation... If this is not the case, the battery pack is identified as a defective or faulty battery (S16). Here, the critical SOC deviation that can be identified as a fault can be determined. It can be set to, for example, 20%. Additionally, a critical SOC deviation (where a fault reaches a level that triggers a warning signal) can be determined. The setting can be, for example, 10%. If the battery is determined to be faulty, the BMS can shut down both the charging FET and the discharging FET, and stop charging and discharging operations. Additionally, if the battery is determined to be defective, the BMS can generate a warning signal and, in response to the generated warning signal, control the charging FET or discharging FET to operate in the corresponding mode.

[0060] At the same time, if the voltage deviation between units is less than the critical voltage deviation, and the SOC deviation between libraries is less than the critical SOC deviation ( If the battery pack is identified as normal (S15), then the battery pack is determined to be normal.

[0061] However, Figure 2 The method for detecting short circuits within battery cells shown has a problem: it cannot quickly diagnose defects or faults within the battery pack because it is provided at a level where imbalances between cells or between batteries can only be detected when the battery pack has been stored for a long period of time and is actually used.

[0062] Figure 3 This is an operation flowchart of a battery diagnostic method according to an embodiment of the present invention.

[0063] The battery diagnostic method according to embodiments of the present invention can be performed by a battery diagnostic device. The battery diagnostic device according to embodiments of the present invention can be a battery management system (BMS), or can be included as part of a battery management system.

[0064] Reference Figure 3 In the battery diagnostic method according to an embodiment of the present invention, firstly, it is monitored whether the battery pack comprising multiple cells has reached full charge and whether the battery pack has entered a dormant (REST) ​​state after full charge (S210). Furthermore, for the battery diagnostic method according to the present invention, it is preferable to meet the conditions of a battery pack SOC of 95% or higher and a temperature of ±25°C.

[0065] The battery diagnostic device can determine whether a first time period has elapsed since the battery pack entered the REST state (S220), and measure a first voltage at the point where the first time period has elapsed (S221). Subsequently, the battery diagnostic device can confirm whether a second time period has elapsed since the battery pack entered the REST state (S230), and measure a second voltage at the point where the second time period has elapsed (S231). Here, the second time period can be set to be longer than the first time period; for example, the first time period can be set to 2 hours, and the second time period can be set to 6 hours. Here, the voltage can be measured as the open-circuit voltage (OCV) of the battery pack.

[0066] Meanwhile, when the battery enters a dormant state, the BMS can limit or terminate the operation of devices or components associated with unnecessary operations based on the battery status. However, even when the BMS is in, for example, a low-power mode, the real-time clock (RTC) can still operate. The RTC is a circuit that is always powered on and connected regardless of whether the BMS is operating. The RTC has a program that calculates time internally and can be used by setting initial values, alarm cycles, etc. In embodiments of the present invention, the elapsed time of a first time period and the elapsed time of a second time period can be confirmed by using the functions of the RTC.

[0067] The battery diagnostic device can calculate the self-discharge of the battery pack based on the first voltage and the second voltage measured in this manner (S240). Here, the self-discharge of the battery pack can be calculated by using a SOC-voltage correlation curve to obtain a first SOC matching the first voltage and a second SOC corresponding to the second voltage, and by using the difference between the first SOC and the second SOC.

[0068] Subsequently, the battery diagnostic device can determine the state of the battery pack by comparing the self-discharge of the battery pack with a predefined critical discharge current (S250). Here, the predefined critical discharge current can represent the self-discharge current generated when a short circuit occurs inside the battery cell.

[0069] Meanwhile, the critical discharge current can be classified as follows: a first critical discharge current, indicating a permanent failure has occurred in the battery pack; a second critical discharge current, indicating a repairable fault has occurred in the battery pack; and a third critical discharge current, indicating a minor anomaly in the battery pack that is less than a repairable fault. Here, the minor anomaly associated with the third critical discharge current can include situations where the battery cell is in a low voltage state but not in a short-circuit state.

[0070] Figure 4 This is a graph showing the SOC-voltage correlation for calculating self-discharge according to an embodiment of the present invention.

[0071] exist Figure 4 In the graph, the horizontal axis represents the SOC (%) of the battery pack, and the vertical axis represents the open-circuit voltage (OCV) of the battery pack. For example... Figure 4 As shown, the SOC-voltage correlation can vary with temperature. Figure 4 (The curves based on the first temperature and the curves based on the second temperature are different), and as a desired condition for battery diagnosis according to an embodiment of the present invention, it is appropriate to maintain the temperature at approximately ±25°C during the diagnosis.

[0072] As described above, the OCV of the battery pack can be measured at a first time point (t1) after a first time period has elapsed since the battery pack was fully charged, and the voltage value at the first time point (t1) can be obtained. Here, the first SOC corresponding to the first voltage value measured at the first time point (t1) can be obtained through the SOC-voltage correlation curve.

[0073] Additionally, the OCV of the battery pack can be measured at a second time point (t2) after a second time period has elapsed since the battery pack was fully charged, and the voltage value at the second time point (t2) can be obtained. Here, the second SOC corresponding to the second voltage value measured at the second time point (t2) can be obtained through the SOC-voltage correlation curve.

[0074] Subsequently, the difference between the first SOC and the second SOC can be calculated, and the self-discharge of the battery pack can be calculated based on the difference between the first SOC and the second SOC and the nominal capacity of the battery pack. Here, the nominal capacity can refer to the capacity [Ah] of the battery set by the battery manufacturer during development.

[0075] Figure 5a This is a graph showing the results of a self-discharge current measurement experiment when a short circuit occurs inside the cell. Figure 5b This is a graph showing the results of a voltage measurement experiment when a short circuit occurs inside the cell.

[0076] like Figure 5a As shown, the results of the self-discharge current measurement experiment when a short circuit occurs inside the unit can be used to derive the critical current according to an embodiment of the present invention.

[0077] As experimental conditions, experiments were performed on various sample cells (including those with internal short circuits) with a SOC of 100%. The temperature during the experiment was 25°C, and the total experimental period was 5 days. Here, a constant current (CC) / constant voltage (CV) charging method was used to achieve a full charge to 100% SOC.

[0078] The experiment demonstrates the results of measuring the microcurrent flowing in the sample cells under various conditions. Understandably, while there were sample cells where the current remained almost unchanged throughout the entire 5-day experimental period, there were also sample cells where the microcurrent increased significantly in less than a day. Among these sample cells, those exhibiting a very large increase in microcurrent (…) Figure 5a In the case of the P-region, it can be understood that the cell has a short circuit inside the cell. Depending on the degree of microcurrent generation, the corresponding cell can be classified as a cell with an anomaly, a cell with a fault (repairable), or a cell with a permanent failure.

[0079] at the same time, Figure 5b It shows that in relation to Figure 5a The results of voltage changes measured over a 5-day experimental period under identical conditions confirmed that the voltage decrease was greater in cells where a short circuit occurred internally and a large self-discharge current was generated.

[0080] In this invention, the result of a self-discharge current measurement experiment when a short circuit occurs inside the cell is determined as the critical discharge current quantity according to an embodiment of the invention and is utilized.

[0081] Figure 6 This is a detailed operation flowchart of battery diagnostics based on self-discharge according to an embodiment of the present invention.

[0082] exist Figure 6 In the middle, through Figure 4 The overall operation of the battery diagnostic method according to the present invention is described in detail in step S250, which compares the self-discharge of the battery pack with a predefined critical discharge current to determine the state of the battery pack.

[0083] When calculating the self-discharge of the battery pack, the battery diagnostic device can compare the calculated self-discharge with a first critical discharge current (S251). Here, the first critical discharge current is a value corresponding to the current level indicating when a permanent failure occurs in the battery pack. The first critical discharge current can be set, for example, to 10 mAh. If the self-discharge of the battery pack is greater than the first critical discharge current, it is determined that a permanent failure has occurred in the corresponding battery pack (S252). Here, permanent failure can be understood as an unrepairable defect or failure. In the case of permanent failure, the BMS can control the charging FET and discharging FET to turn off.

[0084] If the self-discharge of the battery pack is less than the first critical discharge current, the self-discharge is compared with the second critical discharge current (S253). Here, the second critical discharge current is a value corresponding to the current indicating a repairable fault in the battery pack. The second critical discharge current can be set, for example, to 5 mAh. If the self-discharge of the battery pack is greater than or equal to the second critical discharge current, it can be determined that a fault has occurred in the battery pack (S254). If a fault has occurred in the battery pack, the BMS can control the charging FET and the discharging FET to turn off.

[0085] Additionally, if the self-discharge of the battery pack is less than the second critical discharge current, the self-discharge is compared with the third critical discharge current (S255). Here, the third critical discharge current is a value corresponding to the current indicating an abnormality in the battery pack. The abnormality associated with the third critical discharge current may include a situation where the battery cell is not in a short-circuit state but is in a low-voltage state. The third critical discharge current can be set, for example, to 3 mAh.

[0086] If the self-discharge of the battery pack is greater than or equal to the third critical discharge current, an abnormality can be determined to have occurred in the battery pack, and a warning signal can be generated (S256). On the other hand, if the self-discharge of the battery pack is less than the third critical discharge current, the battery pack can be determined to be normal (S257).

[0087] Figure 7 This is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0088] Reference Figure 7 According to an embodiment of the present invention, the battery diagnostic device 200 can be connected to a battery 100 comprising multiple units, and may include at least one processor 210, a memory 220 storing at least one command executed by the processor, a communication unit 230 for performing data transmission and reception, and an RTC element 290. Here, the battery diagnostic device 200 according to an embodiment of the present invention may be a battery management system (BMS), or may be included as part of a battery management system. Here, the battery 100 may be understood as a battery pack, battery module, or battery assembly, and may be replaced by any term that can refer to a collection of battery cells applied to a particular system or device and used as a power source.

[0089] Here, at least one processor 210 may be referred to as a control unit, controller, microcontroller unit (MCU), etc., and may include a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor thereon that performs the methods according to embodiments of the present invention.

[0090] RTC element 290 is a circuit that is always powered on and connected regardless of whether the BMS is operating, and can provide processor 210 with information about the initial time and the passage of time. Therefore, processor 210 can determine whether a first time period and a second time period have elapsed since the battery entered a sleep state, and can measure the voltage of the battery pack at these time points.

[0091] Here, the processor 210 can execute at least one instruction stored in the memory 220, and the at least one instruction may include: an instruction for monitoring whether the battery pack has entered a dormant state after being fully charged; an instruction for measuring a first voltage after a first time period has elapsed since entering the dormant state; an instruction for measuring a second voltage after a second time period has elapsed since entering the dormant state; an instruction for calculating the self-discharge of the battery pack based on the first voltage and the second voltage; and an instruction for determining the state of the battery pack by comparing the self-discharge of the battery pack with a predetermined critical discharge current.

[0092] Here, the instructions for calculating the self-discharge of the battery pack may include: instructions for using the state of charge (SOC)-voltage correlation to derive a first SOC that matches a first voltage and a second SOC that matches a second voltage; and instructions for using the difference between the first SOC and the second SOC to calculate the self-discharge.

[0093] The first and second voltages can be obtained by measuring the open-circuit voltage (OCV) of the battery pack.

[0094] Instructions for determining the state of a battery pack may include instructions for determining that an anomaly has occurred in at least one of a plurality of battery cells if the self-discharge of the battery pack is greater than or equal to a predetermined critical discharge current.

[0095] Here, the real-time clock (RTC) within the battery management system (BMS) can be used to determine whether the first time period has elapsed and whether the second time period has elapsed.

[0096] Meanwhile, the critical discharge current can indicate the amount of self-discharge current generated when an internal short circuit occurs in the battery cell, and can be obtained in advance through experiments on battery cells in which an internal short circuit occurs.

[0097] Here, the critical discharge current may include: a first critical discharge current indicating that a permanent failure has occurred in the battery pack; a second critical discharge current indicating that a repairable failure has occurred in the battery pack; and a third critical discharge current indicating that a minor anomaly has occurred in the battery pack compared to a repairable failure.

[0098] Furthermore, when the battery diagnostic device according to an embodiment of the present invention is configured to be included in a BMS, the BMS may additionally include a battery monitoring integrated chip (BMIC). Here, the BMIC may be an IC-type component located inside the BMS that measures information such as the voltage, temperature, and current of the battery cells / modules.

[0099] Furthermore, the battery diagnostic device 200 according to an embodiment of the present invention may also include an input interface device 240, an output interface device 250, a storage device 260, etc. The corresponding components included in the battery diagnostic device 200 can be connected via a bus 270 and can communicate with each other.

[0100] Additionally, the memory (or storage cell) of the battery diagnostic device 200 may include at least one of volatile storage media and non-volatile storage media. For example, the memory may include at least one of read-only memory (ROM) and random access memory (RAM).

[0101] According to the embodiments of the present invention described above, abnormalities caused by short circuits in battery cells can be diagnosed within a short period of time without requiring a long battery usage period. Therefore, battery pack safety can be enhanced through more robust battery pack condition diagnosis.

[0102] The operation of the method according to embodiments of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices that store data readable by a computer system. Furthermore, the computer-readable recording medium can be distributed across network-connected computer systems to store and execute computer-readable programs or code in a distributed manner.

[0103] In addition, computer-readable recording media can include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Program instructions can include not only machine language code created by a compiler, but also high-level language code that can be executed by a computer using an interpreter.

[0104] Although some aspects of the invention have been described in the context of apparatus, they may also refer to, according to the description of the corresponding method, blocks or apparatuses corresponding to method steps or features of method steps. Similarly, aspects described in the context of a method may also refer to corresponding blocks or items or features of corresponding apparatuses. Some or all of the method steps may be performed by (or using) hardware devices such as, for example, microprocessors, programmable computers, or electronic circuits. In some embodiments, one or more of the most important method steps may be performed by such apparatuses.

[0105] The present invention has been described above with reference to exemplary embodiments thereof; however, those skilled in the art will understand that various modifications and changes may be made to the invention within the scope of the appended claims without departing from the spirit and scope of the invention as described therein.

Claims

1. A battery diagnostic device for diagnosing the state of a battery pack comprising multiple cells, the device comprising: At least one processor; as well as The memory is configured to store at least one instruction executed by the at least one processor. Wherein, the at least one instruction includes: Commands for monitoring whether the battery pack has entered a dormant state after being fully charged; An instruction for measuring the first voltage after a first time period has elapsed since entering the sleep state; Instructions for measuring the second voltage after a second time period has elapsed since entering the sleep state; Instructions for calculating the self-discharge of the battery pack based on the first voltage and the second voltage; and Instructions for determining the state of the battery pack by comparing the self-discharge amount of the battery pack with a predetermined critical discharge current amount.

2. The apparatus according to claim 1, wherein, The instructions for calculating the self-discharge of the battery pack include: Instructions for using state of charge (SOC)-voltage correlation to derive a first SOC matching the first voltage and a second SOC matching the second voltage; and Instructions for calculating self-discharge using the difference between the first SOC and the second SOC.

3. The apparatus according to claim 1, wherein, The first voltage and the second voltage were obtained by measuring the open-circuit voltage (OCV) of the battery pack.

4. The apparatus according to claim 1, wherein, The instructions for determining the state of the battery pack include: An instruction for determining that an anomaly has occurred in at least one of the plurality of battery cells when the self-discharge of the battery pack is greater than or equal to the predetermined critical discharge current.

5. The apparatus according to claim 1, wherein, The real-time clock (RTC) within the battery management system (BMS) is used to determine whether the first time period has elapsed and whether the second time period has elapsed.

6. The apparatus according to claim 1, wherein, The critical discharge current indicates the amount of self-discharge current generated when an internal short circuit occurs in the battery cell, and is obtained in advance through experiments on battery cells in which an internal short circuit occurs.

7. The apparatus according to claim 6, wherein, The critical discharge current includes: The first critical discharge current indicates that a permanent failure has occurred in the battery pack; The second critical discharge current indicates that a repairable fault has occurred in the battery pack; and The third critical discharge current indicates that a minor anomaly has occurred in the battery pack compared to the repairable fault.

8. A battery diagnostic method, the method comprising: Monitor whether a battery pack consisting of multiple units has entered a dormant state after being fully charged; The first voltage was measured after a first time period had elapsed since the state was entered. The second voltage was measured after a second time period had elapsed since the state of sleep was entered. The self-discharge of the battery pack is calculated based on the first voltage and the second voltage; as well as The state of the battery pack is determined by comparing its self-discharge rate with a predetermined critical discharge current.

9. The method according to claim 8, wherein, Calculating the self-discharge of the battery pack includes: The first SOC matching the first voltage and the second SOC matching the second voltage are derived using the state of charge (SOC)-voltage correlation; and The self-discharge is calculated using the difference between the first SOC and the second SOC.

10. The method according to claim 8, wherein, The first voltage and the second voltage were obtained by measuring the open-circuit voltage (OCV) of the battery pack.

11. The method according to claim 8, wherein, Determining the state of the battery pack includes: If the self-discharge of the battery pack is greater than or equal to the predetermined critical discharge current, it is determined that an anomaly has occurred in at least one of the plurality of battery cells.

12. The method according to claim 8, wherein, The real-time clock (RTC) within the battery management system (BMS) is used to determine whether the first time period has elapsed and whether the second time period has elapsed.

13. The method according to claim 8, wherein, The critical discharge current indicates the amount of self-discharge current generated when an internal short circuit occurs in the battery cell, and is obtained in advance through experiments on battery cells in which an internal short circuit occurs.

14. The method according to claim 13, wherein, The critical discharge current includes: The first critical discharge current indicates that a permanent failure has occurred in the battery pack; The second critical discharge current indicates that a repairable fault has occurred in the battery pack; and The third critical discharge current indicates that a minor anomaly has occurred in the battery pack compared to the repairable fault.

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