Battery diagnosis device and battery diagnosis method

Abstract

A battery diagnosis device disclosed in the present document comprises: a sensor unit for acquiring battery cell information about each of one or more battery cells; and a control unit for determining the state of health (SOH) of each of the one or more battery cells on the basis of the battery cell information, and determining whether a defect has occurred in the one or more battery cells on the basis of the average value and the standard deviation of the SOH.

Description

Battery diagnostic device and battery diagnostic method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2023-0108629, filed August 18, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The embodiments disclosed in this document relate to a battery diagnostic device and a battery diagnostic method for diagnosing a battery condition.

[0005] Recently, active research and development is being conducted on secondary batteries. The term "secondary battery" refers to a rechargeable battery, encompassing both conventional Ni / Cd and Ni / MH batteries, as well as more recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of a much higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them suitable for use as power sources for mobile devices. Furthermore, lithium-ion batteries are attracting attention as a next-generation energy storage medium, as their use is expanding to include power sources for electric vehicles.

[0006] When defective battery cells, such as tab open or lithium deposition, occur in these batteries, safety issues may arise during battery use, so research on algorithms for detecting defective battery cells is being conducted. Conventionally, defective battery cells have a characteristic of having a lower capacity than normal battery cells, so a method was used to diagnose a defective battery cell when the State Of Health (SOH) value of the battery cell to be diagnosed was lower by a certain level compared to the median SOH value within the battery module. However, this method can only be applied when the battery system is equipped with a function to estimate SOH, so it is difficult to apply to battery systems that do not have an SOH estimation algorithm, and there was a limitation that the algorithm itself depended on the accuracy of the SOH estimation.

[0007] According to one embodiment disclosed in this document, a battery diagnosis device and a battery diagnosis method based on battery capacity deviation are provided that do not depend on the presence or absence of a battery State Of Health (SOH) estimation algorithm.

[0008] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0009] A battery diagnostic device according to one embodiment includes a sensor unit that obtains battery cell information for each of at least one battery cell, a control unit that determines a State Of Health (SOH) of each of the at least one battery cell based on the battery cell information, and determines whether a defect has occurred in the at least one battery cell based on an average value and a standard deviation of the SOH.

[0010] The control unit may determine that an abnormality has occurred in the cooling control based on the fact that the deviation satisfies a first condition that is greater than or equal to a first reference value for a first reference time.

[0011] The average value of the above SOH may be determined as a reference SOH by excluding the standard deviation from the average value of the SOH, and it may be determined that a defect has occurred in the battery cell based on the SOH of at least one battery cell being lower than the reference SOH.

[0012] The above standard deviation can be determined as a larger value between a standard deviation calculated based on the SOH of each of the at least one battery cells and a preset reference standard deviation.

[0013] The control unit may determine an OCV (Open Circuit Voltage) of at least one battery cell, and determine that a defect has occurred in the battery cell based on the OCV being greater than a reference OCV obtained by excluding an OCV standard deviation from an average OCV.

[0014] The control unit can determine the SOH (State Of Health) of each of the at least one battery cells by applying the current detected by the sensor unit to a current accumulation method.

[0015] The control unit may transmit information about the defective battery cell to an external device based on determining that a defect has occurred in at least one battery cell.

[0016] A battery diagnosis method according to one embodiment includes obtaining battery cell information for each of at least one battery cell, determining a State Of Health (SOH) of each of the at least one battery cell based on the battery cell information, and determining whether a defect has occurred in the at least one battery cell based on an average value and a standard deviation of the SOH.

[0017] Determining whether a defect has occurred in at least one battery cell may include determining a value obtained by excluding the standard deviation from the average value of the SOH as a reference SOH, and determining that a defect has occurred in the battery cell based on the SOH of the at least one battery cell being lower than the reference SOH.

[0018] The average value of the above SOH may include an average value for a preset upper SOH among the SOHs of each of the at least one battery cells.

[0019] The above standard deviation can be determined as a larger value between a standard deviation calculated based on the SOH of each of the at least one battery cells and a preset reference standard deviation.

[0020] Determining whether a defect has occurred in at least one battery cell may include determining an OCV (Open Circuit Voltage) of the at least one battery cell, and determining that a defect has occurred in the battery cell based on the OCV being greater than a reference OCV obtained by excluding an OCV standard deviation from an average OCV.

[0021] Determining the SOH (State Of Health) of each of the at least one battery cell can be accomplished by applying the current detected by the sensor unit to a current accumulation method to determine the SOH (State Of Health) of each of the at least one battery cell.

[0022] A battery diagnostic device according to one embodiment may further include transmitting information about a defective battery cell to an external device based on determining that a defect has occurred in at least one battery cell.

[0023] According to a battery diagnostic device according to one embodiment, it is possible to estimate the SOH (State Of Health) of a battery to determine whether a defect has occurred in a battery cell, thereby preventing capacity reduction, gradual swelling, and ignition that may occur when a defect occurs in a battery cell.

[0024] According to a battery diagnostic device according to one embodiment, since a defect in a battery cell can be detected even when the battery system does not have SOH estimation logic or has low estimation accuracy, the cost for providing a separate SOH estimation logic can be reduced.

[0025] According to a battery diagnosis device according to one embodiment, overdiagnosis can be prevented by utilizing a standard deviation in the process of comparing SOH.

[0026] FIG. 1 illustrates a block diagram of a typical battery system including a battery diagnostic device according to one embodiment.

[0027] FIG. 2 illustrates a block diagram showing the configuration of a battery diagnostic device according to one embodiment.

[0028] FIG. 3 schematically illustrates a flow for determining whether a defect has occurred in a battery cell in a battery diagnostic device according to one embodiment.

[0029] FIG. 4 illustrates a graph that a battery diagnostic device according to one embodiment utilizes to estimate SOH.

[0030] FIG. 5 illustrates another graph utilized by a battery diagnostic device according to one embodiment to estimate SOH.

[0031] Figure 6 illustrates a flowchart of a battery diagnosis method according to one embodiment.

[0032] FIG. 7 continues the flowchart of a battery diagnosis method according to one embodiment of FIG. 6.

[0033] Hereinafter, various embodiments disclosed in this document will be described in detail with reference to the attached drawings. In this document, identical components in the drawings are designated by the same reference numerals, and redundant descriptions of identical components are omitted.

[0034] With respect to the various embodiments disclosed in this document, specific structural and functional descriptions are merely illustrative for the purpose of explaining the embodiments, and the various embodiments disclosed in this document may be implemented in various forms and should not be construed as being limited to the embodiments described in this document.

[0035] The expressions "first," "second," "first," or "second" used in various embodiments may describe various components, regardless of order and / or importance, and do not limit the components. For example, without departing from the scope of the embodiments disclosed herein, a first component may be renamed a second component, and similarly, a second component may also be renamed a first component.

[0036] The terms used in this document are intended solely to describe specific embodiments and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

[0037] All terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art of the embodiments disclosed herein. Terms defined in commonly used dictionaries may be interpreted as having the same or similar meaning in the context of the relevant technology, and unless explicitly defined herein, they shall not be interpreted in an idealized or overly formal sense. In some cases, even if a term is defined herein, it cannot be interpreted to exclude the embodiments disclosed herein.

[0038] FIG. 1 illustrates a block diagram showing the configuration of a typical battery system including a battery management device according to various embodiments.

[0039] Specifically, FIG. 1 schematically illustrates a battery system (10) and an upper controller (20) included in an upper system according to one embodiment disclosed in this document.

[0040] As illustrated in FIG. 1, the battery system (10) may include a plurality of battery modules (12), a sensor unit (14), a switching unit (16), and a battery diagnostic device (1). At this time, the battery system (10) may be equipped with a plurality of battery modules (12), sensor units (14), switching units (16), and battery diagnostic devices (1).

[0041] A plurality of battery modules (12) may include at least one rechargeable battery cell (13). The battery cell (13) may include a cathode, a cathode material, a cathode material, a separator, an electrolyte, a polymer, and a case. In this case, the plurality of battery modules (12) may be connected in series or in parallel.

[0042] The sensor unit (14) may include a current sensor (2), a voltage sensor (3), and a temperature sensor (not shown).

[0043] The current sensor (2) can detect current for application to the current accumulation method in the process of determining the SOH of the battery cell (13).

[0044] The current sensor (2) may include any configuration that generates a signal corresponding to the size of the charging current, and the current sensor (2) may be installed on a charging / discharging path, which is a path through which the charging / discharging current flows in the battery.

[0045] The current sensor (2) can measure the battery current flowing in the battery, i.e., the charging current and the discharging current, and transmit the measurement results to the battery diagnosis device (1). According to one embodiment, the current sensor (2) can measure the battery current at a predetermined cycle during a charging cycle in which the battery is charged with power from an external device or a discharging cycle in which the battery is discharged, and transmit the measurement results to the battery diagnosis device (1).

[0046] The voltage sensor (3) can be configured to be connected in parallel to the battery, detect the battery voltage, which is the voltage across both terminals of the battery, and generate a voltage signal representing the detected battery voltage.

[0047] The temperature sensor may be configured to measure the battery temperature and generate a temperature signal representing the measured battery temperature. The temperature sensor may be positioned within the case so as to measure a temperature close to the actual temperature of the battery. For example, the temperature sensor may be attached to the surface of at least one battery cell included in the cell group and may detect the surface temperature of the battery cell as the battery temperature.

[0048] The temperature sensor may be configured to measure the external temperature, which is the temperature at a predetermined location away from the battery, and generate a temperature signal representing the measured external temperature. The temperature sensor may be positioned at a predetermined location outside the case where heat exchange between the battery and the atmosphere occurs. According to an embodiment, the temperature sensor may be implemented using one or a combination of two or more known temperature detection elements, such as a thermocouple, a thermistor, or a bimetal. The current flowing in the battery system (10) may be detected. At this time, the detection signal may be transmitted to the battery diagnostic device (1).

[0049] In Fig. 1, the sensor unit (14) is connected between the positive electrode of the battery cell (13) and the switching unit (16), but the configurations and connection relationships between the configurations shown in Fig. 1 are only examples and are not limited thereto.

[0050] The switching unit (16) is connected in series to the (+) terminal side or the (-) terminal side of the battery module (12) to control the charge / discharge current flow of the battery module (12). For example, the switching unit (16) may use at least one relay, magnetic contactor, etc. depending on the specifications of the battery system (10).

[0051] The battery diagnostic device (1) can monitor the voltage, current, temperature, etc. of the battery system (10) and control and manage it to prevent overcharging and overdischarging, etc., and may include, for example, a BMS.

[0052] The battery diagnostic device (1) is an interface for receiving values ​​measured from various parameters, and may include a plurality of terminals and a circuit connected to these terminals to process the values ​​received. In addition, the battery diagnostic device (1) may control the ON / OFF of a switching unit (16), for example, a relay or a contactor, and may be connected to a battery module (12) to monitor the status of each battery module (12).

[0053] In addition, the battery diagnostic device (1) can receive temperature data, voltage data, and current data from the sensor unit (14) to obtain battery status information and diagnose the status of the battery.

[0054] The upper controller (20) can transmit a control signal for controlling the battery module (12) to the battery diagnosis device (1). Accordingly, the operation of the battery diagnosis device (1) can be controlled based on the control signal applied from the upper controller (20). In addition, the battery module (12) may be a component included in an ESS (Energy Storage System). In this case, the upper controller (20) may be a controller (BBMS) of a battery bank including a plurality of battery systems (10) or an ESS controller that controls the entire ESS including a plurality of banks. However, the battery system (10) is not limited to this purpose.

[0055] FIG. 2 illustrates a block diagram showing the configuration of a battery diagnostic device according to one embodiment.

[0056] Referring to FIG. 2, a battery diagnostic device (1) according to one embodiment includes a control unit (100) including at least one processor (110) and a memory (120) and a communication unit (200), and can diagnose a battery by communicating with an external device (4) through the communication unit (200).

[0057] According to an embodiment, an external device (4) communicating with a battery diagnostic device (1) may include a user terminal that transmits a result diagnosed by the battery diagnostic device (1).

[0058] Specifically, when the external device (4) is a user terminal, the control unit (100) of the battery diagnosis device (1) can transmit the battery diagnosis result to the user terminal so that the user can check it. At this time, the user terminal may include, but is not limited to, a personal computer, a terminal, a portable telephone, a smart phone, a handheld device, a wearable device, etc.

[0059] A battery diagnostic device (1) according to one embodiment may refer to any electronic device including a processor (110) and a memory (120), and may be mounted on a vehicle and operated. Each component of the battery diagnostic device (1) will be described in detail below.

[0060] The communication unit (200) may include a wireless communication unit (210) and a wired communication unit (220) to communicate with an external device (4). The communication unit (200) may transmit and receive programs for calculating characteristic values ​​of battery cells, class classification, and lifespan estimation, as well as various data, from a separately provided external server.

[0061] The wireless communication unit (210) may include at least one of a short-range communication module and a long-range communication module.

[0062] The short-range communication module can communicate with an external device (4) adjacent to the battery diagnostic device (1) using a short-range communication method. Here, the short-range communication module can utilize one of the following communication methods: Bluetooth, Bluetooth low energy, infrared data association (IrDA), Zigbee, Wi-Fi, Wi-Fi direct, Ultra Wideband (UWB), or near field communication (NFC).

[0063] The remote communication module may include a communication module that performs various types of remote communication and may include a mobile communication unit. The mobile communication unit may transmit and receive a wireless signal with at least one of a base station, an external terminal, and an external device (4) on a mobile communication network. In addition, the remote communication module may communicate with an external device (4) or an external device (4) such as another electronic device through a surrounding access point (AP). The access point (AP) may connect a local area network (LAN) to which the battery diagnosis device (1) is connected to a wide area network (WAN) to which a communication server is connected. Accordingly, the battery diagnosis device (1) may be connected to the communication server through the wide area network (WAN) with the external device (4) and may communicate with each other.

[0064] The wired communication unit (220) can connect to a wired communication network and communicate with an external device (4) through the wired communication network. For example, the wired communication unit (220) can connect to a wired communication network through Ethernet (IEEE 802.3 technology standard) or connect to a wired communication network through CAN communication, and transmit and receive data with external devices (4) through the wired communication network.

[0065] A battery diagnostic device (1) according to one embodiment may include an input / output interface (not shown). An interface may be provided that connects an input device (not shown) such as a keyboard, mouse, or touch panel, an output device (not shown) such as a display, and a processor (110) to transmit and receive data.

[0066] The memory (120) can store various information necessary for operating the battery diagnostic device (1). Specifically, the memory (120) can store an operating system and a program necessary for operating the battery diagnostic device (1), or store data necessary for operating the battery diagnostic device (1).

[0067] Specifically, the memory (120) can store various programs related to calculating characteristic values ​​of battery cells, classifying classes, and estimating lifespan. In addition, the memory (120) can store various data such as voltage, current, and characteristic value data of each battery cell.

[0068] Additionally, the memory (120) can store the SOC and SOH of the battery cell (13) estimated by the processor (110), and can store the average value and standard deviation of the SOH calculated by the processor (110).

[0069] The memory (120) may include volatile memory (120) such as Static Random Access Memory (S-RAM) and Dynamic Random Access Memory (D-RAM) for temporarily storing data. In addition, the memory (120) may include nonvolatile memory (120) such as Read Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM), and Electrically Erasable Programmable Read Only Memory (EEPROM) for long-term storage of data.

[0070] The processor (110) outputs control signals to control the overall battery diagnostic device (1). The processor (110) may include one or more central processing units (CPUs) and graphics processing units (GPUs). In this case, the processor (110) may be implemented as an array of a plurality of logic gates, or may be implemented as a combination of a general-purpose microprocessor (110) and a memory (120) storing a program that can be executed on the microprocessor (110).

[0071] The aforementioned memory (120) and processor (110) may be included in the control unit (100), and the control unit (100) may control the aforementioned components to determine whether a defect has occurred in the battery cell.

[0072] Specifically, the control unit (100) can determine the SOH (State Of Health) of each of at least one battery cell (13) based on the battery cell (13) information, and can determine whether a defect has occurred in at least one battery cell (13) based on the average value and standard deviation of the SOH.

[0073] In addition, the control unit (100) may determine a value obtained by excluding the standard deviation from the average value of the SOH as a reference SOH, and may determine that a defect has occurred in the battery cell (13) based on the fact that the SOH of at least one battery cell (13) is lower than the reference SOH.

[0074] Additionally, the control unit (100) can determine the OCV (Open Circuit Voltage) of at least one battery cell (13) and determine that a defect has occurred in the battery cell (13) based on the OCV being greater than a reference OCV excluding the OCV standard deviation from the average OCV.

[0075] In addition, the control unit (100) can determine the SOH (State Of Health) of each of at least one battery cell (13) by applying the current detected by the sensor unit (14) to the current accumulation method, and the control unit (100) can transmit information on the defective battery cell (13) to the external device (4) based on the determination that a defect has occurred in at least one battery cell (13).

[0076] Accordingly, the battery diagnostic device (1) according to one embodiment can diagnose whether a defect has occurred in the battery cell (13) based on the SOH average value and standard deviation of the battery cell (13), and thus has a remarkable effect of improving the reliability of the diagnosis.

[0077] FIG. 3 schematically illustrates a flow for determining whether a defect has occurred in a battery cell in a battery diagnostic device according to one embodiment.

[0078] Referring to FIG. 3, the control unit (100) of the battery diagnostic device (1) according to one embodiment can receive a battery current value at a specific point in time from a current sensor (2) and a battery voltage value at a specific point in time from a voltage sensor (3).

[0079] Thereafter, the SOH estimation unit of the control unit (100) can estimate the SOH by substituting the battery current and voltage values ​​into a modified formula that is a modified version of the SOC (State Of Charge) calculation formula. The SOH estimation method will be described later in FIGS. 4 and 5.

[0080] The average and standard deviation calculation unit of the control unit (100) can calculate the average of the estimated SOH for each of the plurality of battery cells (13). That is, the control unit (100) can determine that a defect has occurred in the battery cell (13) to be diagnosed if the SOH of the battery cell (13) to be diagnosed is lower than the average of the estimated SOH for each of the plurality of battery cells (13). At this time, since the SOH of the battery cell (13) is affected by various conditions of charging, such as DOD (Depth Of Discharge), starting SOC, and C-rate (Current rate), the control unit (100) can perform a diagnosis by comparing the SOH with a relative value within the battery module.

[0081] In addition, the average and standard deviation calculation unit of the control unit (100) calculates the standard deviation of the estimated SOH for each of the plurality of battery cells (13), and can utilize the standard deviation to detect whether the battery cell (13) to be diagnosed is defective.

[0082] Specifically, the control unit (100) can calculate the average and standard deviation of the SOH values ​​of the top 50% among the battery cells (13) in the battery module, and the top 50% values ​​can be changed by the administrator. The control unit (100) can prevent the average and standard deviation of the SOH from being affected and distorted by a defective battery cell (13) by utilizing the average and standard deviation of the SOH values ​​of the top 50% among the battery cells (13) in the battery module.

[0083] The control unit (100) can determine a value obtained by excluding n*standard deviation from the average of the calculated SOH as a reference SOH, and if the SOH of the battery cell (13) to be diagnosed is lower than the reference SOH, it can determine that a defect has occurred in the battery cell (13) to be diagnosed. Here, n means an arbitrary constant and can be changed by the administrator.

[0084] At this time, the control unit (100) of the diagnostic device according to one embodiment can apply the following two methods to prevent over-inspection.

[0085] First, in the standard deviation correction unit of the control unit (100), if the standard deviation of the battery cells (13) among the battery modules in which only normal battery cells (13) exist is small, over-inspection may occur, so the calculated standard deviation can be compared with a preset reference standard deviation to correct the standard deviation according to the formula of max(reference standard deviation, calculated standard deviation).

[0086] The control unit (100) can determine a value obtained by excluding the n* corrected standard deviation from the average of the SOH as a reference SOH, and if the SOH of the battery cell (13) to be diagnosed satisfies a condition that is lower than the reference SOH, it can determine that a defect has occurred in the battery cell (13) to be diagnosed.

[0087] Accordingly, in the case of a battery module in which the standard deviation of the battery cells (13) within the battery module is relatively small, the control unit (100) can prevent over-diagnosis by not performing a diagnosis, since the battery cells (13) are not defective even if there is some deviation.

[0088] Second, when the battery is in a low voltage state, the charge start OCV (Open Circuit Voltage) and the charge end OCV are relatively low, so the SOH tends to be estimated to be lower than the average. Therefore, in order to prevent over-inspection due to this, the control unit (100) can determine that a defect has occurred in the battery cell (13) when the charge end OCV of the battery cell (13) to be diagnosed satisfies the condition that it is greater than the charge end OCV average - n*charge end OCV standard deviation.

[0089] Accordingly, over-diagnosis, in which the SOH is estimated to be low and excessive diagnosis is performed even when no defect has occurred in the battery cell (13) when the battery is under voltage, can be prevented.

[0090] Thereafter, the control unit (100) can transmit the diagnosis result to the external device (4) when it is diagnosed that a defect has occurred in the battery cell (13) or when it is diagnosed that the battery cell (13) is normal. At this time, the diagnosis result can include a signal indicating that the battery cell (13) is defective or normal, and can include a diagnosis message indicating that the battery cell (13) is defective or normal.

[0091] FIG. 4 illustrates a graph that a battery diagnostic device according to one embodiment utilizes to estimate SOH, and FIG. 5 illustrates another graph that a battery diagnostic device according to one embodiment utilizes to estimate SOH.

[0092] Referring to FIGS. 4 and 5 together, the control unit (100) can estimate the SOH of each battery cell (13) to diagnose whether the battery cell (13) is defective even in a battery system (10) without an SOH estimation function.

[0093] The control unit (100) may determine point (a) of FIG. 4 as the first current point (current point 1) and point (b) as the second current point (current point 2) based on the charge / discharge cycle of the battery. In addition, the control unit (100) may determine point (a) of FIG. 5 as the first voltage point (voltage point 1) and point (b) as the second voltage point (voltage point 2).

[0094] Thereafter, the control unit (100) can determine the SOH by modifying the SOC calculation formula (Mathematical Formula 1) using the current integration method. Specifically, Mathematical Formula 1 can be modified into Mathematical Formula 2 regarding battery capacity, and the battery capacity can be calculated by substituting the values ​​of the first current point, the second current point, the first voltage point, and the second voltage point into Mathematical Formula 2. The control unit (100) can estimate the SOH of the battery cell (13) by substituting the calculated battery capacity into Mathematical Formula 3 regarding battery capacity.

[0095]

[0096]

[0097]

[0098] According to this, even in a battery system (10) without an SOH estimation function, there is an effect that allows detection of battery cell (13) defects without relying on SOH estimation logic.

[0099] Figure 6 illustrates a flowchart of a battery diagnosis method according to one embodiment.

[0100] Referring to FIG. 6, the control unit (100) can determine whether the battery's charge depth is greater than or equal to a reference depth as an event that initiates battery diagnosis (600). Here, the battery's charge depth may refer to the rate at which the battery is fully charged at a specific point in time based on the capacity at which the battery is fully charged from its initial state.

[0101] For example, the control unit (100) can start a diagnosis to determine a defect in the battery cell (13) only when the charge depth of the battery is 50% or more, and can return to the beginning without starting the diagnosis if the charge depth of the battery is less than the reference depth (No of 600).

[0102] That is, if the control unit (100) determines that the depth of charge of the battery is greater than or equal to the reference depth (example of 600), the control unit (100) can estimate the SOH of the battery cells (13) within the module based on the OCV and current charge amount of the entire battery cells (13) (610). At this time, the control unit (100) can estimate the SOH of each battery cell (13) based on mathematical equations 1 to 3 as described above.

[0103] Thereafter, the control unit (100) can determine the average and standard deviation of the SOH corresponding to the upper reference percentage of all battery cells (13) within the module (620). That is, the control unit (100) can calculate the average and standard deviation only for the top n% of SOH in descending order among the SOH values ​​in order to prevent defective battery cells (13) from affecting the average and standard deviation.

[0104] The control unit (100) can correct the standard deviation to a larger value between the calculated standard deviation and a preset reference standard deviation (630). At this time, the reference standard deviation is a value preset by the administrator and refers to a parameter value for preventing overdiagnosis.

[0105] In addition, the control unit (100) can determine the end-of-charge OCV corresponding to the upper reference percentage among all battery cells (13), and for example, can determine the average and standard deviation of the end-of-charge OCV of the battery cells (13) corresponding to the upper 50% (640). That is, the control unit (100) can utilize the OCV value to prevent over-diagnosis when the battery is in a low voltage state as described above.

[0106] FIG. 7 continues the flowchart of a battery diagnosis method according to one embodiment of FIG. 6.

[0107] Referring to FIG. 7, the control unit (100) can determine that a defect has occurred in the battery cell (13) when both the SOH condition and the OCV condition are satisfied.

[0108] Specifically, the control unit (100) can compare the SOH of the battery cell (13) to be diagnosed with a reference SOH excluding the standard deviation from the SOH average value (700).

[0109] The control unit (100) can determine that the battery cell (13) to be diagnosed is normal if the SOH of the battery cell (13) to be diagnosed is greater than or equal to the reference SOH (No of 700) (730). That is, since the reference SOH is calculated based on the average value of the SOH of the top n% of SOH values ​​within the battery module, the control unit (100) can determine that the SOH of the battery cell (13) to be diagnosed is normal if the SOH of the battery cell (13) to be diagnosed is greater than or equal to the reference SOH.

[0110] The control unit (100) can determine whether the battery cell (13) to be diagnosed satisfies the OCV condition if the SOH of the battery cell (13) to be diagnosed is less than the reference SOH (example of 700). Specifically, the control unit (100) can compare the end-of-charge OCV of the battery cell (13) to be diagnosed with the reference OCV obtained by excluding the OCV standard deviation from the average OCV (710).

[0111] The control unit (100) can determine that the battery cell (13) to be diagnosed is normal if the charge termination OCV of the battery cell (13) to be diagnosed is less than or equal to the reference OCV (No of 710) (730). That is, if the charge termination OCV of the battery cell (13) to be diagnosed is less than or equal to the reference OCV, the battery is in a low voltage state, so the battery cell (13) can be determined to be normal to prevent over-diagnosis.

[0112] The control unit (100) can determine that a defect has occurred in the battery cell (13) if the charge termination OCV of the battery cell (13) to be diagnosed is greater than the reference OCV (example of 710), since it is not in a low voltage state and there is no concern about overdiagnosis (720).

[0113] In Fig. 7, the OCV condition is determined after the SOH condition is determined, but the order is not limited and the two conditions may be determined in parallel.

[0114] In this way, the battery diagnostic device (1) according to one embodiment not only determines whether a battery cell (13) is defective based on the SOH, but also utilizes the standard deviation to prevent over-diagnosis, thereby enabling efficient diagnosis.

[0115] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium storing computer-executable instructions. The instructions may be stored in the form of program code, and when executed by a processor, may generate program modules to perform the operations of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0116] Computer-readable storage media include all types of storage media that store instructions that can be deciphered by a computer. Examples include read-only memory (ROM), random access memory (RAM), magnetic tape, magnetic disks, flash memory, and optical data storage devices.

[0117] Additionally, a computer-readable recording medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0118] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable recording medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be at least temporarily stored or temporarily generated on a machine-readable recording medium, such as a memory (102) of a manufacturer's server, an application store's server, or a relay server.

[0119] Although all components constituting the embodiments disclosed in this document have been described as being combined or operating in combination as one, the embodiments disclosed in this document are not necessarily limited to such embodiments. That is, within the scope of the purpose of the embodiments disclosed in this document, all of the components may be selectively combined and operated one or more times.

[0120] Furthermore, terms such as "include," "comprise," or "have" described above, unless specifically stated otherwise, imply that the corresponding component may be present, and therefore should be interpreted to include other components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as terms defined in dictionaries, should be interpreted to be consistent with the contextual meaning of the relevant technology, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

[0121] The above description is merely an illustrative description of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document. Therefore, the embodiments disclosed in this document are not intended to limit the technical idea of ​​the embodiments disclosed in this document, but to explain it, and the scope of the technical idea disclosed in this document is not limited by these embodiments. The scope of protection of the technical idea disclosed in this document should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of this document.

Claims

1. A sensor unit for obtaining battery cell information for each of at least one battery cell; and A battery diagnostic device comprising a control unit that determines the SOH (State Of Health) of each of the at least one battery cell based on the battery cell information, and determines whether a defect has occurred in the at least one battery cell based on the average value and standard deviation of the SOH.

2. In claim 1, The above control unit, A battery diagnostic device that determines a value excluding the standard deviation from the average value of the SOH as a reference SOH and determines that a defect has occurred in the battery cell based on the SOH of at least one battery cell being lower than the reference SOH.

3. In claim 1, The average value of the above SOH is A battery diagnostic device comprising an average value for a preset upper SOH among the SOH of each of the at least one battery cell.

4. In claim 1, The above standard deviation is, A battery diagnostic device that determines a larger value between a standard deviation calculated based on the SOH of each of the at least one battery cell and a preset reference standard deviation.

5. In claim 1, The above control unit, A battery diagnostic device that determines the OCV (Open Circuit Voltage) of at least one battery cell and determines that a defect has occurred in the battery cell based on the OCV being greater than a reference OCV excluding the OCV standard deviation from the average OCV.

6. In claim 1, The above control unit, A battery diagnostic device that determines the SOH (State Of Health) of each of the at least one battery cell by applying the current detected by the sensor unit to a current accumulation method.

7. In claim 1, The above control unit, A battery diagnostic device that transmits information about a defective battery cell to an external device based on determining that at least one battery cell has a defect.

8. For each at least one battery cell, obtain battery cell information; Determine the SOH (State Of Health) of each of the at least one battery cell based on the battery cell information; A battery diagnosis method comprising: determining whether a defect has occurred in at least one battery cell based on the average value and standard deviation of the SOH.

9. In claim 8, Determining whether at least one battery cell above has failed is: A battery diagnosis method comprising: determining a value obtained by excluding the standard deviation from the average value of the SOH as a reference SOH, and determining that a defect has occurred in the battery cell based on the SOH of at least one battery cell being lower than the reference SOH; 10. In claim 8, The average value of the above SOH is A battery diagnostic method comprising an average value for a preset upper SOH among the SOH of each of the at least one battery cell.

11. In claim 8, The above standard deviation is, A battery diagnosis method wherein the standard deviation is determined based on the SOH of each of the at least one battery cell and a preset reference standard deviation, whichever is greater.

12. In claim 8, Determining whether at least one battery cell above has failed is: A battery diagnostic method for determining an OCV (Open Circuit Voltage) of at least one battery cell and determining that a defect has occurred in the battery cell based on the OCV being greater than a reference OCV obtained by excluding an OCV standard deviation from an average OCV.

13. In claim 8, Determining the SOH (State Of Health) of each of the at least one battery cell, A battery diagnosis method for determining the SOH (State Of Health) of each of at least one battery cell by applying the current detected by the sensor unit to a current accumulation method.

14. In claim 8, A battery diagnosis method further comprising: transmitting information about a defective battery cell to an external device based on determining that a defect has occurred in at least one battery cell.

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