Battery diagnosis apparatus and method

Abstract

A battery diagnosis apparatus according to one embodiment of the present invention is an apparatus for diagnosing the state of a battery pack including a plurality of cells, and may comprise: at least one processor; and a memory for storing at least one command executed through the at least one processor, wherein the at least one command can include the commands of: checking whether the battery pack enters a rest state after being fully charged; measuring a first voltage after a first time elapses after entering the rest state; measuring a second voltage after a second time elapses after entering the rest state; calculating a self-discharge amount of the battery pack on the basis of the first voltage and the second voltage; and determining the state of the battery pack by comparing the self-discharge amount of the battery pack to a preset threshold discharge current amount.

Description

Battery diagnostic device and method

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

[0002] The present invention relates to a battery diagnostic device and method, and more particularly, to a battery diagnostic device and method for diagnosing a battery short circuit using self-discharge amount.

[0003] Secondary batteries are batteries that can be reused through charging even after discharge, and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners. They are also used as medium- to large-scale energy sources such as personal mobility, automobiles, and ESS (Energy Storage Systems) for smart grids.

[0004] Secondary batteries can be used in the form of assemblies such as battery modules or battery packs in which multiple battery cells are connected in series and parallel, or battery racks in which battery packs are connected in series and parallel, depending on the requirements of the system.

[0005] Secondary batteries are manufactured to prevent short circuits by preventing contact between the positive and negative electrodes with a porous insulating film (separator). However, during the battery manufacturing process, this insulation can fail to be properly maintained for various reasons, which can lead to internal short circuits in the battery. A short circuit between the positive and negative electrodes of a lithium-ion battery can lead to fire or explosion. Even if the short circuit is very small, ions can move and current can flow. This condition is commonly referred to as a soft short or micro short. A soft short can cause precipitates to form, which can lead to low-voltage failures.

[0006] Battery cells undergo stability tests, such as overcurrent testing, high-temperature storage testing, short-circuit testing, and penetration testing, during the manufacturing process to assess their safety against potential defects or faults that may occur during battery operation. However, even batteries that pass these stability tests and are shipped can still have residual defects that were not detected during the initial testing. Furthermore, environmental factors can cause issues such as low current and short-circuits during battery use, posing a risk to the safety of the battery pack.

[0007] An object of the present invention to solve the above problems is to provide a battery diagnostic device that diagnoses a low voltage or short-circuit state of a cell in a battery pack.

[0008] Another object of the present invention to solve the above problems is to provide a battery diagnosis method for diagnosing a low voltage or short circuit condition in a battery pack.

[0009] According to one embodiment of the present invention, a battery diagnostic device for achieving the above purpose is a device for diagnosing the 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 through the at least one processor.

[0010] Here, the at least one command may include a command to determine whether the battery pack has entered a resting state after being fully charged; a command to measure a first voltage after a first time has elapsed after entering the resting state; a command to measure a second voltage after a second time has elapsed after entering the resting state; a command to calculate a self-discharge amount of the battery pack based on the first voltage and the second voltage; and a command to determine a state of the battery pack by comparing the self-discharge amount of the battery pack with a preset threshold discharge current amount.

[0011] Here, the command to calculate the self-discharge amount of the battery pack may include a command to derive a first SOC matching the first voltage and a second SOC matching the second voltage using a state of charge (SOC)-voltage correlation; and a command to calculate the self-discharge amount using a difference between the first SOC and the second SOC.

[0012] The first voltage and the second voltage can be obtained by measuring the OCV (Open Circuit Voltage) of the battery pack.

[0013] The command for determining the status of the battery pack may include a command for determining that an abnormality has occurred in at least one of the plurality of battery cells when the self-discharge amount of the battery pack is greater than or equal to a preset threshold discharge current amount.

[0014] Here, whether the first time has elapsed and whether the second time has elapsed can be determined using the RTC (Real Time Clock) inside the BMS (Battery Management System).

[0015] Meanwhile, the above critical discharge current amount represents the self-discharge current amount that occurs when an internal short circuit occurs in a battery cell, and can be obtained in advance through an experiment on a battery cell in which an internal short circuit occurs.

[0016] At this time, the critical discharge current amount may include a first critical discharge current amount indicating that a permanent failure has occurred in the battery pack; a second critical discharge current amount indicating that a repairable defect has occurred in the battery pack; and a third critical discharge current amount indicating that a minor abnormality than the repairable defect has occurred in the battery pack.

[0017]

[0018] According to an embodiment of the present invention for achieving the above-described other object, a battery diagnosis method may include: a step of checking whether a battery pack including a plurality of cells has entered a resting state after being fully charged; a step of measuring a first voltage after a first time has elapsed after entering the resting state; a step of measuring a second voltage after a second time has elapsed after entering the resting state; a step of calculating a self-discharge amount of the battery pack based on the first voltage and the second voltage; and a step of comparing the self-discharge amount of the battery pack with a preset threshold discharge current amount to determine a state of the battery pack.

[0019] The step of calculating the self-discharge amount of the battery pack may include a step of deriving a first SOC matching the first voltage and a second SOC matching the second voltage using a state of charge (SOC)-voltage correlation; and a step of calculating the self-discharge amount using a difference between the first SOC and the second SOC.

[0020] The first voltage and the second voltage can be obtained by measuring the OCV (Open Circuit Voltage) of the battery pack.

[0021] The step of determining the state of the battery pack may include a step of determining that an abnormality has occurred in at least one of the plurality of battery cells when the self-discharge amount of the battery pack is greater than or equal to a preset threshold discharge current amount.

[0022] Here, whether the first time has elapsed and whether the second time has elapsed can be determined using the RTC (Real Time Clock) inside the BMS (Battery Management System).

[0023] Meanwhile, the above critical discharge current amount represents the self-discharge current amount that occurs when an internal short circuit occurs in a battery cell, and can be obtained in advance through an experiment on a battery cell in which an internal short circuit occurs.

[0024] At this time, the critical discharge current amount may include a first critical discharge current amount indicating that a permanent failure has occurred in the battery pack; a second critical discharge current amount indicating that a repairable defect has occurred in the battery pack; and a third critical discharge current amount indicating that a minor abnormality than the repairable defect has occurred in the battery pack.

[0025] According to the above-described embodiment of the present invention, it is possible to diagnose an abnormality caused by a short circuit in a battery cell within a short period of time without using the battery for a long period of time.

[0026] Accordingly, the safety of the pack can be enhanced by diagnosing the condition of a more robust battery pack.

[0027] Figure 1 is a block diagram of a battery system to which the present invention can be applied.

[0028] Figure 2 is a schematic flowchart of a conventional method for determining an internal short circuit in a battery system.

[0029] Figure 3 is an operation flowchart of a battery diagnosis method according to an embodiment of the present invention.

[0030] FIG. 4 is a graph showing the SOC-voltage correlation used to calculate self-discharge amount according to an embodiment of the present invention.

[0031] Figure 5a is a graph showing the results of a self-discharge current measurement experiment when a short circuit occurs within a cell. Figure 5b is a graph showing the results of a voltage measurement experiment when a short circuit occurs within a cell.

[0032] Figure 6 is a detailed operation flowchart of a battery diagnosis process according to self-discharge amount according to an embodiment of the present invention.

[0033] Figure 7 is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0034] 100: Battery 200: Battery Diagnostic Device

[0035] 210: Processor 220: Memory

[0036] 230: Communications unit 290: RTC component

[0037] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0038] Terms such as "first," "second," "A," and "B" may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component." The term "and / or" includes any combination of multiple related items listed or any one of multiple related items listed.

[0039] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0040] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0041] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0042]

[0043] Some terms used in this specification are defined as follows:

[0044] A battery cell is the smallest unit that stores electricity, and a battery module is a collection of multiple battery cells that are electrically connected.

[0045] A battery assembly is a collection of multiple electrically connected battery cells that function as a power source when applied to a specific system or device. Here, the battery assembly may refer to a battery bank, battery pack, battery module, or battery rack, but the scope of the present invention is not limited to these entities.

[0046] SOC (State of Charge) is the current charged state of the battery expressed as a percentage [%], and SOH (State of Health) is the current deterioration state of the battery expressed as a percentage [%].

[0047]

[0048] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0049]

[0050] Figure 1 is a block diagram of a battery system to which the present invention can be applied.

[0051] Referring to FIG. 1, a battery pack (100) may be configured to include a plurality of battery cells connected in series and parallel. More specifically, a plurality of battery cells may be connected in parallel to form a single battery bank, and a plurality of battery banks may be connected in series to form a battery pack. That is, the battery pack (100) may be configured to include a plurality of battery banks including a plurality of battery cells connected in parallel. In the embodiment of FIG. 1, a single battery bank includes four battery cells connected in parallel. Additionally, a single battery pack includes 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 the embodiment presented in FIG. 1, and the present invention may be applied to battery packs configured with various connection types and various numbers of cells and banks.

[0052] Meanwhile, a battery pack may also be referred to as a battery module, depending on the system to which it is applied. Furthermore, the term "battery pack" can be understood interchangeably as any term that refers to an assembly of battery cells that function as a power source when applied to a specific system or device.

[0053] A battery pack is connected to a load through positive and negative terminals and can perform charging / discharging operations. A battery management system (BMS) (200) is installed in such a battery pack. In this specification, a battery system is used as a concept including one or more battery packs (100) and a battery management device (200). In addition, a battery management device (200) may be included within a battery pack (100), and the battery pack may be used in the same / similar sense as a battery system.

[0054] A battery management system (BMS) (200) monitors the current, voltage, and temperature of the battery pack, calculates the SOC (State Of Charge) based on the monitoring results, and controls charging and discharging. Here, the SOC (State of Charge; charging rate) expresses the current charged state of the battery as a percentage [%].

[0055] The battery management system (BMS) (200) can also evenly balance charge between battery cells or battery banks to extend the life of the battery system. To perform such operations, the BMS (200) may include various components such as fuses, current sensing elements, thermistors, switches, and balancers.

[0056]

[0057] Figure 2 is a schematic flowchart of a conventional method for determining an internal short circuit in a battery system.

[0058] Battery management devices can typically detect internal cell short circuits by detecting inter-bank voltage differences and SOC differences. Figure 2 illustrates a typical method for determining internal cell short circuits using the bank imbalance diagnostic function of a BMS.

[0059] Referring to Fig. 2, the BMS measures the voltage of each cell within the battery pack and checks the voltage difference between cells (S11). At this time, in the battery system illustrated in Fig. 1, since four battery cells included in one bank are connected in parallel, the voltage of each measured cell is identical to the corresponding bank voltage. Therefore, in the battery system illustrated in Fig. 1, the voltage difference between cells can be used in the same sense as the voltage difference between banks. The voltage difference between cells can be measured when the battery is charging, discharging, and at rest, respectively.

[0060] The measured inter-cell voltage difference is compared with the threshold voltage difference (△Vth) (S12), and if the inter-cell voltage difference is greater than the threshold voltage difference, the battery is determined to be defective (S16) and a warning signal is generated. Here, the threshold voltage difference (△Vth) can be set to, for example, 100 mV. In response to the generated warning signal, the BMS can control the charging FET (field effect transistor) or the discharging FET operating in the corresponding mode.

[0061] The BMS checks the SOC of each bank as well as the voltage difference between cells and compares the SOC of each bank (S13). The SOC difference between banks is compared with the critical SOC difference (△SOCth) (S14). If the SOC difference between banks is greater than or equal to the threshold SOC difference (△SOCth), the corresponding battery pack is determined to be a defective or faulty battery (S16). Here, the threshold SOC difference (△SOCth) that can be determined to be a fault can be set to, for example, 20%. In addition, the threshold SOC difference (△SOCth) that can be determined to be a fault to the extent of generating a warning signal can be set to, for example, 10%. If the battery is determined to be defective, the BMS can turn off both the charge FET and the discharge FET and stop the charge / discharge operation. In addition, 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 charge FET (field effect transistor) or the discharge FET operating in the corresponding mode.

[0062] Meanwhile, if the voltage difference between cells is less than the threshold voltage difference and the SOC difference between banks is less than the threshold SOC difference (△SOCth), the battery pack is judged to be normal (S15).

[0063] However, the method for judging internal short circuits in cells as shown in Fig. 2 has a problem in that it cannot quickly diagnose defects or faults within the battery pack, as it is provided at a level where detection of imbalances between cells or banks is possible only when the battery pack is stored for a long period of time and the actual battery pack is used.

[0064]

[0065] Figure 3 is an operation flowchart of a battery diagnosis method according to an embodiment of the present invention.

[0066] The battery diagnosis method according to the present invention can be performed by a battery diagnosis device. The battery diagnosis device according to the present invention can be a battery management system (BMS) or can be included as a part of a battery management system.

[0067] Referring to FIG. 3, the battery diagnosis method according to the present invention first determines whether a battery pack including multiple cells has reached full charge and then enters a resting (REST) ​​state after full charge (S210). Additionally, for the battery diagnosis according to the present invention, it is preferable to satisfy the conditions that the battery pack's SOC is 95% or higher and its temperature is ±25°C.

[0068] The battery diagnostic device checks whether a first period of time has elapsed after the battery pack enters a resting (REST) ​​state (S220), and measures a first voltage at the time when the first period of time has elapsed (S221). Thereafter, the battery diagnostic device checks whether a second period of time has elapsed after the battery pack enters a resting (REST) ​​state (S230), and measures a second voltage at the time when the second period of time has elapsed (S231). At this time, the second period of time may be longer than the first period of time, for example, the first period of time may be set to 2 hours, and the second period of time may be set to 6 hours. Here, the voltage may be measured as the OCV (Open Circuit Voltage) of the battery pack.

[0069] Meanwhile, when the battery enters a resting state, the BMS can limit or terminate the operation of devices or components within the BMS associated with unnecessary operations depending on the state of the battery. However, even when the BMS is in a low-power mode, for example, the RTC (Real Time Clock) can operate. The RTC (Real Time Clock) is a circuit that is always powered on and turned on regardless of whether the BMS is operating. The RTC has a program that internally calculates time, and can be used by setting an initial value, an alarm cycle, etc. In an embodiment of the present invention, the elapsed time of the first time and the elapsed time of the second time can be confirmed by using the function of the RTC.

[0070] The battery diagnostic device can calculate the self-discharge amount of the battery pack based on the first voltage and the second voltage measured in this manner (S240). Here, the self-discharge amount of the battery pack can be calculated by deriving a first SOC matching the first voltage and a second SOC corresponding to the second voltage using the SOC-voltage correlation graph, and using the difference between the first SOC and the second SOC.

[0071] Thereafter, the battery diagnostic device can determine the condition of the battery pack by comparing the self-discharge amount of the battery pack with a preset critical discharge current amount (S250). Here, the critical discharge current amount may represent the self-discharge current amount that occurs when an internal short circuit occurs in a battery cell.

[0072] Meanwhile, the critical discharge current may be divided into 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 defect has occurred in the battery pack, and a third critical discharge current indicating that a minor abnormality has occurred in the battery pack other than a repairable defect. Here, the minor abnormality associated with the third critical discharge current may include a case where the battery cell is in a low voltage state but has not reached a short circuit state.

[0073]

[0074] FIG. 4 is a graph showing the SOC-voltage correlation used to calculate self-discharge amount according to an embodiment of the present invention.

[0075] In the graph of Fig. 4, the horizontal axis represents the SOC (%) of the battery pack, and the vertical axis represents the OCV (Open Circuit Voltage) of the battery pack. As shown in Fig. 4, the correlation between SOC and voltage may vary depending on temperature (the graphs for the first and second temperatures in Fig. 4 are different), and it is appropriate that the temperature be maintained at approximately ±25°C during diagnosis as a desirable condition for the battery diagnosis according to the present invention.

[0076] As previously explained, the OCV (Open Circuit Voltage) of the battery pack can be measured at a first time point (t1) after a first period of time has elapsed since the battery pack was fully charged, and the voltage value at the first time point (t1) can be obtained from this. At this time, the first SOC corresponding to the first voltage value measured at the first time point (t1) can be derived through the SOC-voltage correlation graph.

[0077] Additionally, the OCV (Open Circuit Voltage) of the battery pack can be measured at a second time point (t2) after a second period of time has elapsed since the battery pack was fully charged, and the voltage value at the second time point (t2) can be obtained from this. At this time, a second SOC corresponding to the second voltage value measured at the first time point (t2) can be derived through the SOC-voltage correlation graph.

[0078] Thereafter, the difference between the first SOC and the second SOC is calculated, and the self-discharge amount of the battery pack can be calculated from the difference between the first SOC and the second SOC and the nominal capacity of the battery pack. Here, the nominal capacity refers to the set capacity [Ah] of the battery set by the battery manufacturer during development.

[0079]

[0080] Figure 5a is a graph showing the results of a self-discharge current measurement experiment when a short circuit occurs within a cell. Figure 5b is a graph showing the results of a voltage measurement experiment when a short circuit occurs within a cell.

[0081] The results of the self-discharge current measurement experiment when a short circuit occurs within a cell as shown in Fig. 5a can be used to derive the critical discharge current amount according to the embodiment of the present invention.

[0082] Under experimental conditions, experiments were conducted on various sample cells with SOC 100% (including samples with internal short circuits). The temperature during the experiment was 25°C, and the experiment period was 5 days in total. Here, a CC (Constant Current) / CV (Constant Voltage) charging method was used to reach full charge to SOC 100%.

[0083] This experiment presents the results of measuring microcurrents flowing in sample cells in various states. While some sample cells show almost no change in current over the five-day experimental period, others show a pattern of extremely large increases in microcurrents in less than a day. Among these, those sample cells showing a very large increase in microcurrents (region P in Fig. 5a) can be seen as cells with internal short circuits. Depending on the degree of microcurrent generation, these cells can be classified as abnormal cells, defective cells (repairable cells), or permanently damaged cells.

[0084] Meanwhile, Fig. 5b shows the results of voltage changes measured over a five-day experimental period under the same conditions as Fig. 5a. It can be seen that the voltage decrease is significant in cells where a short circuit occurs within the cell, resulting in a large self-discharge current.

[0085] In the present invention, the results of a self-discharge current measurement experiment when a short circuit occurs within a cell are set as the critical discharge current amount according to the embodiment of the present invention and utilized.

[0086]

[0087] Figure 6 is a detailed operation flowchart of a battery diagnosis process according to self-discharge amount according to an embodiment of the present invention.

[0088] In FIG. 6, among the entire operations of the battery diagnosis method according to the present invention as seen through FIG. 4, the detailed operation of the step (S250) of comparing the self-discharge amount of the battery pack with a preset critical discharge current amount to determine the state of the battery pack is examined.

[0089] When the self-discharge amount of the battery pack is calculated, the battery diagnostic device compares the calculated self-discharge amount with a first threshold discharge current amount (S251). Here, the first threshold discharge current amount is a value corresponding to the current amount indicated when a permanent failure occurs in the battery pack. The first threshold discharge current amount may be set to, for example, 10 mAh. If the self-discharge amount of the battery pack is greater than or equal to the first threshold discharge current amount, it is determined that a permanent failure has occurred in the battery pack (S252). At this time, a permanent failure can be regarded as a defect or failure that cannot be cured. If a permanent failure occurs, the BMS can control the charging FET (field effect transistor) and the discharge FET to be turned off.

[0090] If the self-discharge amount of the battery pack is less than the first threshold discharge current, the self-discharge amount is compared with the second threshold discharge current (S253). Here, the second threshold discharge current is a value corresponding to the current amount indicated when a repairable fault occurs in the battery pack. The second threshold discharge current may be set to, for example, 5 mAh. If the self-discharge amount of the battery pack is greater than or equal to the second threshold discharge current, it is determined that a fault has occurred in the battery pack (S254). If a fault has occurred in the battery pack, the BMS may control the charging FET (field effect transistor) and the discharging FET to be OFF.

[0091] Additionally, if the self-discharge amount of the battery pack is less than the second critical discharge current, the self-discharge amount is compared with the third critical discharge current (S255). Here, the third critical discharge current is a value corresponding to the current amount indicated when an abnormality occurs in the battery pack. Here, an abnormality associated with the third critical discharge current may include a case where the battery cell is in a low voltage state but has not reached a short-circuit state. The third critical discharge current may be set to, for example, 3 mAh.

[0092] If the self-discharge of the battery pack is greater than or equal to the third critical discharge current, the battery pack is determined to be abnormal and a warning signal is 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 is determined to be normal (S257).

[0093]

[0094] Figure 7 is a block diagram of a battery diagnostic device according to an embodiment of the present invention.

[0095] Referring to FIG. 7, a battery diagnosis device (200) according to the present invention is connected to a battery (100) including a plurality of cells, and may include at least one processor (210), a memory (220) storing at least one command executed by the processor, a communication unit (230) performing data transmission and reception, and an RTC element (290). Here, the battery diagnosis device (200) according to the present invention may be a battery management system (BMS) or may be included as a part of a battery management system. Here, the battery (100) may be understood as a battery pack, a battery module, a battery assembly, etc., and any term may be substituted as long as it means a collection of battery cells that are applied to a specific system or device and function as a power supply source.

[0096] Here, at least one processor (210) may be referred to as a control unit, a controller, an MCU (Micro Controller Unit), etc., and may include a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed.

[0097] The RTC element (290) is a circuit that is always powered and turned on regardless of whether the BMS is operating, and can provide information on the initial time and the passage of time to the processor (210). Accordingly, the processor (210) can check whether the first time has elapsed and the second time has elapsed since the battery entered a resting state, and measure the voltage of the battery pack at that point.

[0098] Here, the processor (210) can execute at least one command stored in the memory (220), and the at least one command may include a command to check whether the battery pack has entered a resting state after being fully charged; a command to measure a first voltage after a first time has elapsed after entering the resting state; a command to measure a second voltage after a second time has elapsed after entering the resting state; a command to calculate a self-discharge amount of the battery pack based on the first voltage and the second voltage; and a command to determine a state of the battery pack by comparing the self-discharge amount of the battery pack with a preset threshold discharge current amount.

[0099] Here, the command to calculate the self-discharge amount of the battery pack may include a command to derive a first SOC matching the first voltage and a second SOC matching the second voltage using a state of charge (SOC)-voltage correlation; and a command to calculate the self-discharge amount using a difference between the first SOC and the second SOC.

[0100] The first voltage and the second voltage can be obtained by measuring the OCV (Open Circuit Voltage) of the battery pack.

[0101] The command for determining the status of the battery pack may include a command for determining that an abnormality has occurred in at least one of the plurality of battery cells when the self-discharge amount of the battery pack is greater than or equal to a preset threshold discharge current amount.

[0102] Here, whether the first time has elapsed and whether the second time has elapsed can be determined using the RTC (Real Time Clock) inside the BMS (Battery Management System).

[0103] Meanwhile, the above critical discharge current amount represents the self-discharge current amount that occurs when an internal short circuit occurs in a battery cell, and can be obtained in advance through an experiment on a battery cell in which an internal short circuit occurs.

[0104] At this time, the critical discharge current amount may include a first critical discharge current amount indicating that a permanent failure has occurred in the battery pack; a second critical discharge current amount indicating that a repairable defect has occurred in the battery pack; and a third critical discharge current amount indicating that a minor abnormality than the repairable defect has occurred in the battery pack.

[0105] Meanwhile, 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 BMIC (Battery Monitoring Integrated Chip). Here, the BMIC may be an IC-type component located within the BMS and measuring information such as voltage, temperature, and current of a battery cell / module.

[0106] The battery diagnostic device (200) may also include an input interface device (240), an output interface device (250), a storage unit (260), etc. Each component included in the battery diagnostic device (200) may be connected by a bus (270) to communicate with each other.

[0107] The memory (or storage device) of the battery diagnostic device (200) may be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0108]

[0109] According to the embodiments of the present invention described above, abnormalities caused by short-circuiting of battery cells can be diagnosed within a short period of time, without requiring prolonged battery use. Consequently, the safety of the battery pack can be enhanced through more robust condition diagnosis.

[0110]

[0111] The operations of the method according to an embodiment 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 any type of recording device that stores data readable by a computer system. Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable program or code to be stored and executed in a distributed manner.

[0112] Additionally, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0113] While some aspects of the present invention have been described in the context of a device, they may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a corresponding block or item or a feature of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most significant method steps may be performed by such a device.

[0114] Although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A device for diagnosing the status of a battery pack including a plurality of cells, At least one processor; A memory comprising at least one instruction to be executed via at least one processor, At least one of the above commands, A command to check whether the above battery pack has entered a resting state after being fully charged; A command to measure the first voltage after the first time has elapsed after entering the resting state; A command to apply a second voltage after a second time has elapsed after entering the above resting state; A command to calculate the self-discharge amount of the battery pack based on the first voltage and the second voltage; and A battery diagnostic device, comprising a command to determine the condition of the battery pack by comparing the self-discharge amount of the battery pack with a preset threshold discharge current amount.

2. In claim 1, A command to calculate the self-discharge amount of the above battery pack is: A command to derive a first SOC matching the first voltage and a second SOC matching the second voltage using the SOC (state of charge)-voltage correlation; and A battery diagnostic device, comprising a command to calculate a self-discharge amount using the difference between the first SOC and the second SOC.

3. In claim 1, A battery diagnostic device, wherein the first voltage and the second voltage are obtained by measuring the OCV (Open Circuit Voltage) of the battery pack.

4. In claim 1, The command to determine the status of the above battery pack is: A battery diagnostic device including a command for determining that at least one of the plurality of battery cells has a problem when the self-discharge amount of the battery pack is greater than or equal to a preset threshold discharge current amount.

5. In claim 1, A battery diagnostic device that determines whether the first time period has elapsed and whether the second time period has elapsed using an RTC (Real Time Clock) within a BMS (Battery Management System).

6. In claim 1, The above critical discharge current is, A battery diagnostic device that indicates the amount of self-discharge current that occurs when an internal short circuit occurs in a battery cell, and is obtained in advance through an experiment on a battery cell where an internal short circuit has occurred.

7. In claim 6, The above critical discharge current is, A first critical discharge current amount indicating that a permanent failure has occurred in the above battery pack; a second critical discharge current amount indicating that a repairable defect has occurred in the battery pack; and A battery diagnostic device, comprising a third critical discharge current amount indicating that a lesser abnormality than the above-mentioned curable defect has occurred in the above-mentioned battery pack.

8. A step for checking whether a battery pack containing multiple cells has entered a resting state after being fully charged; A step of measuring a first voltage after a first period of time has elapsed after entering a resting state; A step of measuring a second voltage after a second time has elapsed after entering the above resting state; A step of calculating the self-discharge amount of the battery pack based on the first voltage and the second voltage; and A battery diagnosis method, comprising a step of determining the state of the battery pack by comparing the self-discharge amount of the battery pack with a preset threshold discharge current amount.

9. In claim 8, The step of calculating the self-discharge amount of the above battery pack is: A step of deriving a first SOC matching the first voltage and a second SOC matching the second voltage using the SOC (state of charge)-voltage correlation; and A battery diagnosis method, comprising a step of calculating the self-discharge amount using the difference between the first SOC and the second SOC.

10. In claim 8, A battery diagnosis method, wherein the first voltage and the second voltage are obtained by measuring the OCV (Open Circuit Voltage) of the battery pack.

11. In claim 8, The step of judging the status of the above battery pack is: A battery diagnosis method, comprising a step of determining that at least one of the plurality of battery cells is abnormal when the self-discharge amount of the battery pack is greater than or equal to a preset threshold discharge current amount.

12. In claim 8, A battery diagnosis method that determines whether the first time period and the second time period have elapsed using an RTC (Real Time Clock) within a BMS (Battery Management System).

13. In claim 8, The above critical discharge current is, A battery diagnostic method that indicates the amount of self-discharge current that occurs when an internal short circuit occurs in a battery cell, and is obtained in advance through an experiment on a battery cell in which an internal short circuit has occurred.

14. In claim 13, The above critical discharge current is, A first critical discharge current indicating that a permanent failure has occurred in the above battery pack; a second critical discharge current amount indicating that a repairable defect has occurred in the battery pack; and A battery diagnostic method, comprising a third critical discharge current amount indicating that a less severe abnormality than the above-mentioned curable defect has occurred in the above-mentioned battery pack.

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