Battery system diagnostic apparatus and method

Abstract

The invention relates to a battery system diagnostic apparatus and method. Disclosed is a battery diagnosis technique capable of effectively diagnosing a defective battery cell among a plurality of battery cells included in a battery system in an early stage. The battery system diagnostic device diagnoses a battery system including a plurality of battery cells having electrode tabs therein, and includes: a cell measurement unit configured to measure a voltage or a current for each of the plurality of battery cells; and a processor configured to calculate an SOH for each battery cell multiple times over time by using the voltage or current measured by the cell measurement unit, and detect a battery cell having a defect in the electrode tab among the plurality of battery cells based on the SOH of each battery cell calculated multiple times.

Description

[0001] This application is a divisional application of Chinese invention patent application "Battery System Diagnostic Device and Method", which entered the Chinese national phase on August 9, 2022, with PCT application number PCT / KR2022 / 000094, international filing date of January 4, 2022, and Chinese application number 202280002612.7. Technical Field

[0002] This application claims priority to Korean Patent Application No. 10-2021-0004822, filed in Korea on January 13, 2021, the disclosure of which is incorporated herein by reference.

[0003] This disclosure relates to a battery diagnostic technique, and more specifically, to a battery diagnostic technique capable of diagnosing defective battery cells in a battery system comprising multiple battery cells. Background Technology

[0004] Currently commercially available rechargeable batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), nickel-zinc (NiZn), and lithium-ion batteries. Among them, lithium-ion batteries have attracted much attention because they have virtually no memory effect compared to nickel-based batteries, and their very low discharge rate and high energy density ensure free charging and discharging.

[0005] Lithium-ion secondary batteries primarily use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively. Additionally, a lithium-ion secondary battery includes: an electrode assembly containing positive and negative electrode plates coated with positive and negative electrode active materials, respectively, with a separator inserted between the positive and negative electrode plates; and an external casing for enclosedly housing the electrode assembly along with the electrolyte.

[0006] Generally, based on their external shape, lithium secondary batteries can be classified into can-type secondary batteries, in which the electrode components are built into a metal can, and pouch-type secondary batteries, in which the electrode components are built into a pouch made of aluminum laminated sheets. In particular, pouch-type secondary batteries tend to be more widely used due to their advantages such as ease of stacking and light weight.

[0007] Pouch-type secondary batteries can be manufactured by injecting electrolyte while the electrode assembly is housed outside the pouch and then sealing the outside of the pouch.

[0008] Figure 1 This is an exploded perspective view showing a typical pouch-type secondary battery, and Figure 2 It is shown Figure 1 A perspective view of a pouch-shaped secondary battery.

[0009] like Figure 1 and Figure 2As shown, the pouch-type secondary battery 1 may include an electrode assembly 20 and a pouch exterior 30 for housing the electrode assembly 20.

[0010] Here, the electrode assembly 20 has a basic structure including a positive electrode plate, a negative electrode plate, and a separator inserted between the positive and negative electrode plates, and can be housed in an internal space I formed inside the bag exterior 30. At this time, the bag exterior 30 can be formed with an upper bag 31 and a lower bag 32, and a sealing portion S is provided on the outer peripheral surfaces of the upper bag 31 and the lower bag 32, such that the sealing portions S adhere to each other to seal the internal space I in which the electrode assembly 20 is housed.

[0011] Here, at least one positive terminal piece 11 and at least one negative terminal piece 12 may extend from the positive and negative electrode plates, respectively. Additionally, the positive terminal piece 11 and the negative terminal piece 12 may be coupled to plate-shaped electrode leads—that is, plate-shaped positive lead 41 and plate-shaped negative lead 42—respectively. Furthermore, a portion of the positive lead 41 and a portion of the negative lead 42 may be exposed outside the bag exterior 30 to provide externally configured electrode terminals for electrical connection to, for example, another secondary battery or an external device.

[0012] As the applications of rechargeable batteries have expanded, in recent years they have become widely used not only in small devices such as portable electronic devices but also in medium to large devices such as vehicles and energy storage systems (ESS) for driving or energy storage. In the case of such medium to large devices, a large number of rechargeable batteries can be connected in series and / or parallel to increase output or capacity. In particular, in the case of energy storage systems, a very large number of rechargeable batteries can be included. For example, an energy storage system may include multiple battery racks, and each battery rack can be configured to house multiple battery modules within the rack frame. Furthermore, each battery module may include several rechargeable batteries, and each rechargeable battery may be referred to as a battery cell. Therefore, an energy storage system may include a very large number of battery cells, such as thousands to tens of thousands of battery cells.

[0013] In such a battery system, diagnosing the condition of each individual cell is crucial. However, as the number of cells increases, it becomes difficult to diagnose the condition of specific cells and detect defective ones. Furthermore, many different types of failures can occur in individual cells. For example, various problems can arise within a cell, such as external damage, separator damage, the formation of metallic foreign objects, electrolyte leakage, and terminal defects. Among these, terminal defects can occur when at least one positive terminal 11 or negative terminal 12—i.e., electrode terminal 10—located inside the cell is disconnected or causes a contact error. If such a terminal defect occurs, the performance of the corresponding cell may deteriorate or it may fail, thus potentially degrading the overall performance and reliability of the battery system. Additionally, if a problem such as a terminal defect occurs in a specific cell, that cell may catch fire and cause a fire throughout the battery system.

[0014] Therefore, it is crucial to identify which battery cell among the numerous individual cells in a battery system is faulty and what type of defect has occurred. In particular, diagnosing a defective cell at an early stage is essential. However, an effective method for diagnosing such defective cells, or even specific defect types, at an early stage has yet to be proposed. Summary of the Invention

[0015] Technical issues

[0016] This disclosure is designed to solve the problems of related technologies, and therefore this disclosure is committed to providing a battery system diagnostic apparatus and method that can effectively diagnose defective battery cells among multiple battery cells included in a battery system at an early stage, as well as a battery system including the battery system diagnostic apparatus.

[0017] These and other objects and advantages of this disclosure may be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure may be achieved by the means shown in the appended claims and combinations thereof.

[0018] Technical solution

[0019] In one aspect of this disclosure, a battery system diagnostic apparatus is provided for diagnosing a battery system comprising a plurality of battery cells having electrode terminals. The apparatus includes: a cell measurement unit configured to measure voltage or current for each of the plurality of battery cells; and a processor configured to calculate the state of equilibrium (SOH) for each battery cell multiple times over time using the voltage or current measured by the cell measurement unit, and to detect, based on the multiple calculated SOH for each battery cell, a battery cell among the plurality of battery cells that has a defect in the electrode terminals.

[0020] Here, the processor can be configured to compare the SOH calculation value with a threshold, so that disconnection defects and incomplete contact defects are detected separately as defects in the electrode terminals.

[0021] In addition, when the calculated SOH value is equal to or less than the threshold for more than the number of times the first criterion is met, the processor can be configured to detect that the corresponding battery cell has a disconnection defect.

[0022] In addition, when the number of times the SOH calculated value switches up / down relative to the threshold continuously exceeds the number of times the second criterion is applied, the processor can be configured to detect that the corresponding battery cell has an incomplete contact defect.

[0023] Additionally, the processor can be configured to indicate whether the number of up / down switches is increasing or decreasing.

[0024] Alternatively, the threshold can be set based on the state of harmonics (SOH) of at least some of the multiple battery cells.

[0025] Additionally, the processor can be configured to detect defective battery cells by distinguishing between the charging and discharging processes for each individual cell.

[0026] Additionally, the processor can be configured to set preconditions for calculating SOH for each battery cell, such that the preconditions for the charging process and the preconditions for the discharging process are set differently from each other.

[0027] In another aspect of this disclosure, a battery system is also provided, which includes a battery system diagnostic device according to this disclosure.

[0028] In another aspect of this disclosure, a battery system diagnostic method is also provided for diagnosing a battery system comprising a plurality of battery cells having electrode terminals in the battery cells. The method includes: measuring voltage or current for each of the plurality of battery cells; calculating state of equilibrium (SOH) for each battery cell multiple times over time using the voltage or current measured in the measurement step; and detecting, based on the SOH of each battery cell calculated multiple times in the calculation step, a battery cell among the plurality of battery cells that has a defect in the electrode terminals.

[0029] Beneficial effects

[0030] According to this disclosure, in a battery system comprising multiple battery cells, defective battery cells can be effectively diagnosed.

[0031] In particular, according to embodiments of this disclosure, problematic battery cells in the electrode terminals within internal components can be detected quickly.

[0032] Furthermore, according to embodiments of this disclosure, the types of problems that have occurred in the electrode terminals can be specifically classified.

[0033] Therefore, according to embodiments of this disclosure, appropriate follow-up measures, such as separation, repair, and replacement, can be performed on defective battery cells, particularly those with abnormalities in the electrode terminals.

[0034] Furthermore, according to embodiments of this disclosure, since specific information regarding the defect types of battery cells can be obtained, the battery cell manufacturing process can be appropriately modified based on the obtained information. Therefore, in this case, the defect rate of battery cells can be reduced.

[0035] Furthermore, this disclosure can have various other effects, which will be described in more detail below. Additionally, any effect that can be readily understood by one skilled in the art will not be described in detail with respect to each component. Attached Figure Description

[0036] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are intended to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as limited to the drawings.

[0037] Figure 1 This is an exploded perspective view showing a typical pouch-type secondary battery.

[0038] Figure 2 It is shown Figure 1 A perspective view of a pouch-shaped secondary battery.

[0039] Figure 3 This is a block diagram schematically illustrating the functional configuration of a battery system diagnostic apparatus according to an embodiment of the present disclosure.

[0040] Figure 4 It is a graph showing the SOH calculated by the processor according to an embodiment of the present disclosure for any single cell, together with a threshold to be compared.

[0041] Figure 5 It is a graph showing the SOH calculated by the processor according to an embodiment of the present disclosure for another battery cell, together with a threshold to be compared with it.

[0042] Figure 6 This is a graph showing the SOH calculated by a processor according to an embodiment of the present disclosure for a single battery cell.

[0043] Figure 7 This is a graph showing the calculated SOH values ​​of several battery cells included in a battery system according to an embodiment of the present disclosure.

[0044] Figure 8 This is a flowchart illustrating, schematically, a battery system diagnostic method according to an embodiment of the present disclosure. Detailed Implementation

[0045] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but rather interpreted based on the meaning and concepts corresponding to the technical aspects of the present disclosure, on the basis that the inventors are permitted to appropriately define the terminology to obtain the best description.

[0046] Therefore, the description presented herein is merely a preferred example for illustrative purposes only and is not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0047] Figure 3 This is a block diagram schematically illustrating the functional configuration of a battery system diagnostic apparatus according to an embodiment of the present disclosure.

[0048] like Figure 3 As shown, the battery system may include multiple battery cells 1. Here, battery cell 1 may refer to a secondary battery. The secondary battery may be one of them, such as... Figure 1 and Figure 2The electrode assembly 20 shown is housed within a pouch-type secondary battery in an outer pouch 30, and the secondary battery can also be a can-type secondary battery in which the electrode assembly is housed in a cylindrical or prismatic metal can. The battery cell 1, which is to be diagnosed by the battery system diagnostic apparatus of this disclosure, can be selected from various secondary batteries known as of the filing date of this application.

[0049] Specifically, the battery cell 1 may include electrode terminals 10. For example, refer to... Figure 1 The electrode assembly 20 of the battery cell 1 may include at least one positive electrode plate and at least one negative electrode plate. Additionally, a positive electrode terminal 11 and a negative electrode terminal 12 may be respectively disposed on the positive electrode plate and the negative electrode plate. Furthermore, the positive electrode terminal 11 may be connected to the positive electrode lead 41, and the negative electrode terminal 12 may be connected to the negative electrode lead 42. This is well known as of the filing date of this application, therefore the internal configuration of the battery cell 1 will not be described in detail here.

[0050] A battery system may include multiple such secondary batteries (cell 1). That is, a battery system is a system comprising multiple cell 1, and can refer to a system configured to charge and discharge electricity. Battery systems can include various types of systems, such as battery modules, battery packs, battery racks, and energy storage systems (ESS). Specifically, in a battery system, multiple secondary batteries may be connected in series and / or in parallel.

[0051] The battery system diagnostic apparatus according to this disclosure can be considered as an apparatus for diagnosing a battery system comprising a plurality of battery cells 1 having electrode terminals therein, as described above.

[0052] In particular, the battery system diagnostic device according to this disclosure may include a single cell measurement unit 100 and a processor 200.

[0053] The cell measurement unit 100 can be configured to measure the voltage or current for each of the plurality of battery cells 1 included in the battery system. For example, the cell measurement unit 100 may include a voltage sensor and can be configured to measure the voltage across each battery cell 1 included in the battery system. Alternatively, the cell measurement unit 100 may include a current sensor and can be configured to measure the current flowing in each battery cell 1. Here, the cell measurement unit 100 may measure only one of the voltage or current of each battery cell 1, or it may be configured to measure both the voltage and current of each battery cell 1.

[0054] In addition, for each battery cell 1, the cell measurement unit 100 can be configured to measure battery characteristics other than voltage or current, such as the temperature of the battery cell 1, charging time, discharging time, or number of charge / discharge cycles.

[0055] The cell measurement unit 100 can be configured to measure the characteristics of all the battery cells 1 included in the battery system, such as the voltage of all the battery cells 1. However, this disclosure is not limited to this configuration, and the cell measurement unit 100 can be configured to measure the voltage or current of only some of the battery cells 1 included in the battery system.

[0056] The battery system diagnostic apparatus according to this disclosure can employ various battery measurement devices known as of the filing date of this application as the single-cell measurement unit 100 of this disclosure. Therefore, the single-cell measurement unit 100 will not be described in detail herein.

[0057] The processor 200 can be electrically connected to the cell measurement unit 100 and receive measurement data from the cell measurement unit 100. In particular, since the cell measurement unit 100 can measure the voltage or current for each of the plurality of cell 1, the processor 200 can receive information from the cell measurement unit 100 about the voltage or current measured in this manner for each cell 1.

[0058] Additionally, the processor 200 can calculate the State of Health (SOH) for each battery cell 1 using the voltage or current measurement value of each battery cell 1 sent as described above. Here, the SOH of each battery cell 1 refers to its state of health and can be calculated based on the voltage or current of the battery cell 1. SOH calculation methods are widely known in various forms as of the filing date of this application, and therefore will not be described in detail here. Furthermore, in the battery system diagnostic apparatus according to this disclosure, the processor 200 can employ an SOH calculation method known as of the filing date of this application to calculate the SOH.

[0059] Processor 200 can calculate SOH multiple times for each battery cell 1. Specifically, processor 200 can be configured to calculate SOH multiple times over time for each battery cell 1. For example, processor 200 can be configured to calculate SOH daily, weekly, or monthly for each battery cell 1. Alternatively, processor 200 can be configured to calculate SOH for each battery cell 1 whenever the cycle count increases by a predetermined number of times. For example, processor 200 can be configured to calculate SOH for each battery cell 1 whenever the cycle count increases by 10.

[0060] Therefore, since the processor 200 obtains the SOH calculation result for each battery cell 1 over time, the processor 200 can have multiple SOH calculation results for each battery cell 1. For example, the processor 200 can have 50 SOH calculation results for each battery cell 1 within a predetermined time period.

[0061] Furthermore, the processor 200 can be configured to detect defective battery cells 1 based on multiple calculations of the State of Health (SOH) for each battery cell 1. That is, the processor 200 can be configured to obtain multiple SOH calculation results for each battery cell 1 and use these multiple obtained SOH calculation results to detect which of the multiple battery cells 1 included in the battery system is problematic.

[0062] Specifically, the processor 200 can be configured to detect battery cells 1 with defects in the electrode terminals by using the SOH calculation results for each battery cell 1. For example, as Figure 3 As shown, when the battery system includes multiple battery cells 1, the processor 200 can diagnose which of the multiple battery cells 1 has a defect in the electrode terminals.

[0063] According to this configuration of the present disclosure, defective battery cells can be diagnosed early by using the state of harmonics (SOH) of each battery cell 1. In particular, according to this configuration, battery cells 1 with defects in the electrode terminals 10 can be accurately detected at an early stage. Therefore, problems caused by defects in the electrode terminals 10, such as overall performance degradation, malfunctions, or fires of the battery system, can be effectively prevented.

[0064] Processor 200 may optionally include a central processing unit (CPU), application-specific integrated circuit (ASIC), chipset, logic circuit, register, communication modem, data processing device, etc., known in the art, to run the various control logics executed in this disclosure, or these terms may be used to express the same idea. Alternatively, when the control logic is implemented in software, processor 200 may be implemented as a set of program modules. In this case, the program modules may be stored in internal memory or external memory module 400, etc., and run by processor 200. Memory module 400 may be located inside or outside processor 200 and may be connected to processor 200 by various known means.

[0065] In particular, if the battery system includes a control device called a microcontroller unit (MCU) or a battery management system (BMS), the processor 200 can be implemented by a component such as the configured MCU or BMS.

[0066] Furthermore, in this specification, terms such as “for” or “configured to” for the operation or function of the processor 200 may include the meaning of “programmed to”.

[0067] In addition, the battery system diagnostic device according to this disclosure may also include, for example: Figure 3 The notification unit 300 shown.

[0068] The notification unit 300 can be configured to send the detection results performed by the processor 200 to a user or the like. For example, the notification unit 300 may include a display monitor, speaker, warning light, etc., and display the defective cell detection results to the user in various ways, such as visual and auditory methods. Specifically, the notification unit 300 can be configured to send the user information about which of the plurality of battery cells 1 included in the battery system has a defect in its electrode terminals, such as identification information or location information of the defective battery cell. Furthermore, the notification unit 300 can be connected to various wired or wireless communication networks known as of the filing date of this application, and can be connected to a user's mobile terminal or an external server. In this case, the notification unit 300 can send defective cell detection information to a portable terminal or server via a communication network.

[0069] Furthermore, the battery system diagnostic device according to this disclosure may further include, for example: Figure 3 The memory unit 400 shown.

[0070] The memory unit 400 may store programs and data necessary for the cell measurement unit 100 or the processor 200 to perform their functions. That is, the memory unit 400 may store data or programs necessary for at least some components of the battery system diagnostic apparatus according to embodiments of the present disclosure to perform their operations and functions, or data generated during the performance of their operations and functions. For example, the memory unit 400 may store multiple SOH calculation values ​​measured each time for each battery cell 1.

[0071] The memory unit 400 can employ any information storage means known in the art capable of unlimited writing, erasing, updating, and reading of data. As examples, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. Furthermore, the memory unit 400 may store program code defining processes that can be executed by the unit measurement unit 100 and / or the processor 200.

[0072] The processor 200 can be configured to compare a calculated SOH value with a threshold. Here, the threshold is the value to be compared with the calculated SOH value, and can be a criterion value used to determine whether the calculated SOH value of the corresponding battery cell 1 is normal. In particular, the threshold can be considered as an SOH value capable of distinguishing whether an electrode terminal defect has occurred in the corresponding battery cell 1. The threshold can be expressed as a specific value or as a specific range.

[0073] The threshold can be pre-stored in the processor 200 itself or in the memory unit 400 for use by the processor 200.

[0074] Furthermore, multiple thresholds can be set based on the passage of time. That is, the SOH of each battery cell 1 is calculated multiple times over time, and a threshold corresponding to each SOH calculated in this way can be set. For example, when the SOH is calculated for each battery cell 1 monthly, such as January, February, March, etc., thresholds such as January threshold, February threshold, March threshold, etc., can also be set monthly. In this case, the thresholds can be set differently from each other, but at least some thresholds can be set the same as each other.

[0075] The processor 200 can diagnose defects in the electrode terminals based on a comparison between the calculated SOH value and a threshold. Specifically, the processor 200 can be configured to detect whether the defect in the electrode terminals is a disconnection defect or an incomplete contact defect. Here, a disconnection defect can mean a state where one or more electrode terminals 10 included in the battery cell 1 are completely severed at a specific location. For example, in a battery cell 1 including ten electrode terminals 10, a disconnection defect can mean a state where at least one electrode terminal 10 is completely severed. An incomplete contact defect can mean a state where one or more electrode terminals 10 included in the battery cell 1 are severed at a specific location and then repeatedly come into contact. For example, an incomplete contact defect can mean a state where there is a severed portion in at least one electrode terminal 10, but intermittent contact occurs at the severed portion.

[0076] According to this configuration of the present disclosure, electrode terminal defects in the battery cell 1 are detected using SOH calculation values, and the type of electrode terminal defect can even be diagnosed separately. Therefore, in this case, more appropriate measures can be taken based on the type of electrode terminal defect.

[0077] In particular, since incomplete contact defects are characterized by repeated attachment and separation of the cut portion of the electrode connector 10, it is predictable that physical external forces will be applied to the electrode connector 10 or the battery cell 1. Therefore, in such cases, more appropriate actions can be taken relative to the external force applied to the corresponding battery cell 1. For example, when a battery cell 1 with an incomplete contact defect exists, the corresponding situation can be sent to the user through the notification unit 300. At this time, the user can identify the cause of the external force and take appropriate measures to eliminate the cause of the external force, such as stopping the battery system or improving the fixing force of the battery frame.

[0078] In this embodiment, the processor 200 can be configured to determine whether the number of times the calculated SOH value is less than or equal to a threshold has continuously exceeded a first criterion. Furthermore, when the number of times the calculated SOH value is less than or equal to the threshold has continuously exceeded the first criterion, the processor 200 can be configured to detect the corresponding battery cell 1 as having a disconnection defect. (Refer to...) Figure 4 This will be described in more detail.

[0079] Figure 4 It is a graph showing the SOH calculated by the processor 200 according to an embodiment of the present disclosure for any single battery cell 1, together with a threshold to be compared with it.

[0080] refer to Figure 4 The graph B1 indicates the SOH calculated for a specific cell 1 during a predetermined time period—that is, between d1 and d2. Specifically, in graph B1, the SOH values ​​calculated for the time period between d1 and d2 are indicated by points, and such points are connected by lines.

[0081] In addition, Figure 4 In this context, the threshold to be compared with the calculated SOH value B1 is indicated by A1. Specifically, threshold A1 can be set to correspond to each of the calculated SOH values ​​during the time period d1 to d2 in order to compare with multiple calculated SOH values, such as... Figure 4 As shown. Furthermore, the threshold A1 can be configured to change during the time period between d1 and d2, rather than remaining constant. That is, the threshold corresponding to each calculation cycle of SOH can be configured differently.

[0082] In this embodiment, the processor 200 can determine whether the calculated SOH B1 is equal to or less than the threshold A1. Furthermore, if there are portions of the calculated SOH B1 that are equal to or less than the threshold A1, the processor 200 can determine whether the situation where the calculated SOH B1 is equal to or less than the threshold A1 continues for more than a first criterion number of times. Here, the first criterion number can be appropriately set according to various factors such as the specifications of the battery cell 1 or the operating conditions of the battery system. The first criterion number can be preset and stored in the memory unit 400 or the processor 200. As an example, the first criterion number can be set to 5 times. In this case, the processor 200 can determine whether the situation where the calculated SOH B1 is equal to or less than the threshold A1 continues for 5 or more times.

[0083] As a more specific example, see [reference] Figure 4 As time progresses from d1 to d2, processor 200 can identify portions where the calculated SOH value B1 is less than the threshold A1. In this case, processor 200 can extract portions e1, e2, and e3 as consecutive segments from these portions. Furthermore, processor 200 can determine whether the portion where the calculated SOH value B1 is less than the threshold A1 continues for more than a first criterion number of times. For example, when the first criterion number is set to 5 times, processor 200 can identify portions where the calculated SOH value B1 is less than the threshold A1 for 5 or more consecutive times.

[0084] exist Figure 4 In part e1, the SOH calculated value B1 being less than the threshold A1 lasts only once, while in part e2, the SOH calculated value B1 being less than the threshold A1 lasts only twice. Therefore, when part e1 or part e2 is identified, the processor 200 may not determine that an electrode connection defect has occurred in battery cell 1. However, in part e3, the SOH calculated value B1 being less than the threshold A1 lasts five or more times. Therefore, when part e3 is identified, the processor 200 can determine that an electrode connection defect has occurred in battery cell 1. Specifically, the processor 200 can detect a disconnection defect relative to the corresponding battery cell 1 from the first time point da when part e3 begins. That is, if the state of SOH calculated value B1 being less than the threshold A1 lasts for a predetermined time or longer, the processor 200 can determine that the electrode connection is disconnected for the corresponding battery cell 1. In addition, when the SOH calculated value B1 being less than the threshold A1 lasts for more than the first criterion number of times, the processor 200 can determine that the capacity of the corresponding battery cell 1 has deteriorated. In addition, the processor 200 can send the capacity degradation judgment result to the user through the notification unit 300.

[0085] At the same time, Figure 4 In the embodiments described, a disconnection defect or capacity degradation of battery cell 1 is detected based on the number of times the SOH calculated value B1 is equal to or less than the threshold A1. However, it can also be configured to detect the disconnection defect of battery cell 1 based on the time when the SOH calculated value B1 is equal to or less than the threshold A1. For example, if the SOH calculated value B1 of a particular battery cell 1 is less than or equal to the threshold A1 for a certain number of days (e.g., 4 days), the processor 200 can be configured to detect the disconnection defect for the corresponding battery cell 1.

[0086] Simultaneously, even if the number of times the calculated SOH value B1 is equal to or less than the threshold A1 is judged to be greater than or equal to the number of times according to the first criterion, if the calculated SOH B1 within a predetermined time from this point onwards is judged to be greater than the threshold A1, the processor 200 can cancel the judgment on the disconnection defect detected for the corresponding battery cell 1. For example, based on Figure 4 In the embodiment, if the calculated SOH value B1 is equal to or greater than the threshold A1 for more than a predetermined number of times after point e3, the processor 200 can cancel the disconnection defect judgment made at the time point e3. In this case, the disconnection defect can be judged more accurately.

[0087] Furthermore, if the processor 200 determines a disconnection defect, various additional information can be obtained depending on the time point of defect determination. For example, if a cell is determined to have a disconnection defect in the initial stage when it is installed into the battery system, and if the cell is in the BOL (Beginning of Life) state, i.e., if the cell is in a state immediately after manufacturing, it can be determined that a problem existed during the manufacturing process of the corresponding cell. Therefore, in this case, information related to the manufacturing process of the corresponding cell can be sent to help resolve the problem in the manufacturing process of the corresponding cell. If the corresponding cell is in the MOL (Middle of Life) state, i.e., if the cell is in a state of use to some extent, information about the problem can be obtained by tracking the existing usage history, etc. Alternatively, if a cell is determined to have a disconnection defect after being installed into the battery system and in a state of use to some extent, problems with the operating system or operating conditions or problems at the manufacturing time point can be further and comprehensively examined.

[0088] Additionally, the processor 200 can be configured to determine whether the number of up / down switching times of the SOH calculated value relative to a threshold continuously exceeds the number of times a second criterion is applied. Furthermore, the processor 200 can be configured to detect an incomplete contact defect relative to the corresponding battery cell 1 when the number of up / down switching times continuously exceeds the number of times the second criterion is applied. (Refer to...) Figure 5 This will be described in more detail.

[0089] Figure 5 It is a graph showing the SOH calculated by the processor 200 according to an embodiment of the present disclosure for another battery cell 1, together with a threshold to be compared with it.

[0090] refer to Figure 5 Indicates the period from d1 to d2 for targeting and Figure 4 The calculated SOH curve for another battery cell 1, different from cell 1, is illustrated in graph B2. Furthermore, in graph B2, the calculated SOH value at each time point is shown as a point, and these points are connected by a line. Figure 5 The threshold and with Figure 4 The threshold is shown in the same way.

[0091] In this embodiment, when the calculated SOH B2 is compared with a threshold A1, the processor 200 can identify portions greater than or equal to the threshold A1 and switch to portions less than the threshold A1. That is, the processor 200 can count the number of times or time periods when the calculated SOH value B2 increases after being less than the threshold A1 or decreases after being higher than the threshold A1.

[0092] For example, processor 200 can Figure 5The configuration identifies the switching point of the SOH calculated value B2 relative to the threshold A1. Furthermore, the processor 200 can determine whether the number of consecutive switching points is equal to or greater than the second criterion count. Here, the second criterion count can be appropriately set according to various factors such as the specifications of the battery cell 1 or the operating conditions of the battery system. Additionally, the second criterion count can be preset and stored in the memory unit 400 or the processor 200. For example, the second criterion count can be set to 3 times. In this case, when the SOH calculated value B2 switches with respect to the threshold A1 3 times or more consecutively, the processor 200 can determine that there is an incomplete contact defect in the electrode terminals of the corresponding battery cell 1.

[0093] As a more specific example, see Figure 5 As time progresses from d1 to d2, the processor 200 can identify f1, f2, f3, ..., f11 as time points when the calculated SOH value B2 is switched vertically based on a threshold A1. Specifically, the vertical switching time point can be the point where the curves of the calculated SOH value B2 and the threshold A1 intersect. Furthermore, the processor 200 can determine whether each switching time point persists for more than a second criterion number of times, for example, three or more times. Here, the persistence of a switching time point can be considered as meaning that the switching portion relative to the threshold occurs continuously between operation time points at three or more SOH calculation time points.

[0094] exist Figure 5 In the embodiments, at time points f1, f2, and f3, the switching count can be considered not consecutive, but rather a single switching occurrence. Furthermore, at f4 and f5, since two switching portions occur at the three consecutive SOH calculation time points, the consecutive switching count can be considered to correspond to two separate occurrences. Because the consecutive switching count is less than 3 (the second criterion), the processor 200 can disregard the possibility that the battery cell 1 has incomplete contact defects at time points f1 to f5.

[0095] However, the SOH threshold switches continuously from time point f6 to time point f11. That is, starting from time point f6, the number of times the calculated SOH value switches relative to the threshold continues to be as many as 6 times, which can be considered to exceed the second criterion number (3 times). Therefore, in this case, the processor 200 can determine that an incomplete contact defect has occurred in the electrode terminals of the battery cell 1. An incomplete contact defect can be considered as a situation where one electrode terminal repeatedly attaches to another electrode terminal or electrode lead inside the battery cell 1 and then separates from it. If the calculated SOH value B2 fluctuates continuously up and down based on the threshold A1 as described above, the processor 200 can determine that an incomplete contact defect has occurred in the corresponding electrode terminals of the battery cell 1. Furthermore, if the calculated SOH value B2 fluctuates continuously up and down based on the threshold A1, the processor 200 can determine that the capacity of the corresponding battery cell 1 is unstable. Additionally, the processor 200 can send this information to the user through the notification unit 300.

[0096] According to this embodiment, the presence of incomplete contact defects in the electrode terminals of the battery cell 1 can be effectively identified by comparing the calculated SOH value B2 with the threshold A1.

[0097] At the same time, Figure 5 In one embodiment, a configuration is described for identifying the presence of incomplete contact defects in the electrode terminals of battery cell 1 by comparing the calculated SOH value B2 of each battery cell 1 with a threshold A1. However, incomplete contact defects in the electrode terminals can also be identified solely by the calculated SOH value. (Refer to...) Figure 6 This will be described in more detail.

[0098] Figure 6 This is a graph showing the SOH calculated by the processor 200 according to an embodiment of the present disclosure for another battery cell 1.

[0099] refer to Figure 6 The graph B3 illustrates the SOH calculated for any single cell 1 during the time period from d3 to d4. Here, again, the SOH value calculated at each time point is indicated by points, and these points are connected by lines. However, compared to... Figure 4 and Figure 5 Unlike in China, in Figure 6 The threshold is not shown.

[0100] The processor 200 can calculate the change in SOH between each calculation relative to a graph of SOH calculation results. Here, the change in SOH can refer to the difference between consecutive calculated SOH values. Furthermore, the processor 200 can be configured to compare the calculated change in SOH with a graph obtained from... Figure 6The change in SOH is compared with the criterion change indicated by Mt. Next, if the change in SOH is greater than the criterion change Mt for more than a predetermined number of times, such as the third criterion number, the processor 200 can be configured to detect that the corresponding cell 1 has an incomplete contact defect.

[0101] More specifically, in Figure 6 In the configuration, the portion where the SOH change exceeds the criterion change Mt is indicated by g1 to g7. Among these, the consecutive occurrences in g1 and g2 are 2 times. Additionally, the consecutive occurrences in g3 to g7 are 5 times. If the third criterion occurrence is 3 times, the processor 200 can determine that, given that the SOH change exceeds the criterion change Mt, there are three or more consecutive occurrences of incomplete contact defects in the electrode terminals of the corresponding cell 1 at time points g3 to g7.

[0102] In the above embodiments, the processor 200 can be configured to consider the preceding mode as the number of times the SOH change is greater than the criterion change Mt. More specifically, if the SOH change increases or decreases in the same pattern as the preceding mode, the processor 200 may not count the SOH change being greater than the criterion change Mt, even if the SOH change is greater than the criterion change Mt. That is, the processor 200 can only count the SOH change being greater than the criterion change Mt when the SOH change increases or decreases in a different pattern than the preceding mode. For example, if the SOH change increases in the calculation results of a previous number of times and decreases in the calculation results of a current number of times, or if the SOH change decreases in the calculation results of a previous number of times and increases in the calculation results of a current number of times, the processor 200 can be configured to determine whether the SOH change is greater than the criterion change Mt. In this case, by oscillating the SOH calculated value up and down, the processor 200 can count the number of times when the amplitude of the oscillation is equal to or greater than a certain level (criterion change) and detect the incomplete contact defect of the corresponding battery cell 1 based on the counting results.

[0103] According to this configuration of the present disclosure, even without setting a threshold to be compared with SOH, electrode connection defects of the battery cell 1 can be detected, particularly the presence of incomplete contact defects. Therefore, the process for storing or calculating the threshold may not be necessary.

[0104] Additionally, the processor 200 can be configured to identify whether the number of times the SOH calculated value switches up / down relative to a threshold increases or decreases. That is, the processor 200 can count the number of times the SOH calculated value switches from up to down or from down to up based on a threshold. Furthermore, the processor 200 can record each count and identify whether the number of switches gradually increases or decreases over time.

[0105] Specifically, if the number of switching operations gradually increases over time, the processor 200 can determine that there is a high risk of a problem occurring in the electrode terminals. Furthermore, if the number of switching operations increases over time, the processor 200 can determine that the electrode terminals of the corresponding battery cell 1 are progressing from a normal state to an incomplete contact defect state or from an incomplete contact defect state to a disconnection defect state.

[0106] A threshold can be set based on the SOH of at least some of the multiple battery cells 1. Furthermore, the processor 200 can set the threshold based on SOH values ​​calculated for at least some of the battery cells 1 included in the battery system, particularly all of the battery cells 1. (Refer to...) Figure 7 This will be described in more detail.

[0107] Figure 7 This is a graph showing the calculated SOH values ​​of a plurality of battery cells 1 included in a battery system according to an embodiment of the present disclosure.

[0108] refer to Figure 7 The State of Harm (SOH) is calculated for each of the multiple battery cells 1, and the SOH is calculated multiple times over time. Furthermore, the SOH value calculated for each battery cell 1 is displayed each time. Figure 7 In the diagram, the x-axis represents time based on days, while the y-axis represents the SOH calculations as standard deviations. Furthermore, on the y-axis, with the mean of all SOH calculations centered, the deviation based on the center is shown as σ (sigma). Specifically, in... Figure 7 In this context, S1 and S2 represent the limits corresponding to 3σ. The processor 200 can set the value corresponding to 3σ as the standard deviation of the average value as the threshold for each calculation. Furthermore, the processor 200 can detect electrode terminal defects in each battery cell 1 by comparing the value corresponding to 3σ—that is, the threshold—with the calculated SOH value for each battery cell 1. Specifically, the processor 200 can set the lower limits of the two values ​​corresponding to 3σ located on either side of the average value—that is, the threshold S1 corresponding to +3σ and the threshold S2 corresponding to -3σ—as the threshold values.

[0109] According to this configuration of the present disclosure, problems in a specific battery cell 1 can be effectively diagnosed, taking into account the overall condition of the battery system, particularly whether there are defects in the electrode terminals. Furthermore, the state of harmonics (SOH) of the battery cells 1 included in the battery system can vary depending on various factors such as the operating state of the battery system or the surrounding environment. According to this embodiment, since thresholds are appropriately set based on these factors, electrode terminal defects in a specific battery cell 1 can be diagnosed more accurately. Additionally, according to this embodiment, it is not necessary to pre-store the thresholds in the memory unit 400, processor 200, etc.

[0110] At the same time, Figure 7 In this example, the value corresponding to 3σ is exemplified as a threshold, but this is merely an example, and the threshold can be set to another value such as 6σ. That is, the processor 200 can be configured to compare the value corresponding to 6σ, which serves as the threshold, relative to the average value of all battery cells 1, with the SOH of each battery cell 1. Alternatively, the processor 200 can diagnose whether the SOH of each battery cell 1 is abnormal based on the cell-to-cell variation of the SOH value of each battery cell 1, or based on the difference between the SOH value of each battery cell 1 and the average SOH value of the entire battery system. Furthermore, the processor 200 can evaluate the calculated SOH value of each battery cell 1 in various other forms and can determine whether the electrode terminals of the corresponding battery cell 1 are defective.

[0111] When calculating the State of Health (SOH) for each of the plurality of battery cells 1, the processor 200 can be configured such that the criterion time points for the SOH calculation among the battery cells 1 can be the same or have only a time error within a predetermined level. Here, since the SOH calculation is based on the results measured by the cell measurement unit 100, the cell measurement unit 100 can be configured such that the voltage measurement time point or current measurement time point for each of the plurality of battery cells 1 is made in the same or similar time period. For example, when the battery system includes a plurality of battery cells 1, the cell measurement unit 100 can be configured to measure the voltage or current of all battery cells 1 simultaneously in each measurement cycle or within a time error range of less than 1 second.

[0112] According to this configuration of the present disclosure, the reliability of the threshold setting is ensured by allowing the criterion time points for the SOH calculation of battery cell 1 to be the same or within a certain level, and the accuracy of the diagnosis can be improved by comparing the threshold with the calculated value.

[0113] In addition, when a defective battery cell is detected, the processor 200 can be configured to perform the charging and discharging processes separately for each battery cell 1.

[0114] For example, processor 200 can be configured to separately identify a State of Emergency (SOH) mode calculated based on the voltage measured during charging and a State of Emergency (SOH) mode calculated based on the voltage measured during discharging. In this case, thresholds can also be set separately for charging and discharging. For example, thresholds can be set separately as follows: Figure 7 The thresholds shown are in the form of 3σ to correspond to the charging and discharging states, respectively.

[0115] Additionally, the processor 200 can be configured to compare the calculated SOH value during the discharge process with a discharge threshold for each battery cell 1, and to compare the calculated SOH value during the charging process with a charging threshold.

[0116] According to this configuration of the present disclosure, since the charging and discharging processes are compared separately, the state of the battery cell 1 can be diagnosed more accurately. Specifically, the state of harmlessness (SOH) of the battery cell 1 can vary depending on whether it is in a charging or discharging state, and according to this embodiment, SOH can be diagnosed by more appropriately reflecting this situation. Therefore, the accuracy of diagnosing electrode terminal defects in the battery cell 1 can be further improved.

[0117] Specifically, the processor 200 can set preconditions for calculating the State of Health (SOH) for each battery cell 1. That is, the processor 200 can be configured to calculate the SOH only when the predetermined preconditions are met. Alternatively, the processor 200 can be configured not to calculate the SOH if the preconditions are not met.

[0118] For example, processor 200 can use SOC to calculate SOH. Here, the methods for obtaining SOC are well known as of the filing date of this application, and therefore will not be described in detail here.

[0119] More specifically, processor 200 can be configured to calculate SOH via Equation 1 below.

[0120] [Equation 1]

[0121]

[0122] Here, I refers to the current flowing in battery cell 1, f refers to the end time of charging / discharging, and i refers to the start time of charging / discharging. Additionally, SOCf refers to the SOC value at the end of charging / discharging, and SOCi refers to the SOC value at the start of charging / discharging.

[0123] Here, the processor 200 can use the change in SOC during the charging / discharging process as a prerequisite for calculating SOH. In particular, the processor 200 can be configured to calculate the SOH of the corresponding battery cell 1 only when the difference between the SOC value at the beginning of charging and discharging and the SOC value at the end of charging and discharging for each battery cell 1 is equal to or greater than a certain level.

[0124] For example, in Equation 1, regarding the absolute value of the difference between the SOC value at the start of charging and discharging and the SOC value at the end of charging and discharging, the processor 200 can be configured to only when... SOH is only calculated when the charge or discharge process reaches 50% or more. In this case, it can be assumed that SOH is only calculated when the charge or discharge process reaches 50% or more.

[0125] According to this configuration of the present disclosure, SOH can be calculated only when charging or discharging is sufficiently performed above a certain level. In this case, the accuracy and reliability of SOH calculation can be further improved.

[0126] Additionally, the processor 200 can use the time difference between the start and end times of the charging / discharging process as a prerequisite for calculating the State of Harmony (SOH). Specifically, the processor 200 can be configured to calculate the SOH of the corresponding battery cell 1 only when the time difference between the end time of charging / discharging and the start time of charging / discharging for each battery cell 1 is equal to or greater than a certain level.

[0127] For example, in Equation 1, processor 200 can be configured to calculate SOH only when (fi) ≥ 3600s. In this case, SOH can only be calculated if the charging or discharging process lasts for 3600 seconds or longer.

[0128] According to this configuration of the present disclosure, since SOH is only calculated when charging or discharging continues for a predetermined time or longer, the accuracy and reliability of SOH calculation can be further improved.

[0129] Furthermore, the processor 200 can be configured to calculate the SOH when both of the above-mentioned preconditions—namely, the preconditions for the difference between SOCs and the preconditions for the time difference—are satisfied.

[0130] In the above embodiments, the processor 200 can be configured to set different preconditions for the charging process and for the discharging process.

[0131] For example, as a prerequisite during the charging process, processor 200 can be configured to calculate SOH when the SOC is less than or equal to a certain level at the start of charging. That is, processor 200 can be configured not to calculate SOH when the SOC exceeds a predetermined level at the start of charging.

[0132] As a more specific example, processor 200 can be configured to calculate SOH when the battery cell 1 satisfies SOCi ≤ 7 in Equation 1 during the charging process. Here, processor 200 may not calculate SOH when SOCi, which is the SOC at the start of charging, exceeds 7%. According to this embodiment, the problem of deterioration in the accuracy of SOH calculation during charging due to charging only being performed in excessively high SOC ranges can be prevented. Furthermore, in this embodiment, the upper limit of 7% for SOCi can be set differently depending on the specifications of the battery cell 1 or the operating method of the battery system.

[0133] As another example, as a prerequisite during the discharge process, processor 200 can be configured to calculate SOH when the State of Charge (SOC) is greater than or equal to a certain level at the start of the discharge. That is, processor 200 can be configured not to calculate SOH when the SOC is less than a certain level at the start of the discharge.

[0134] As a more specific example, during the discharge process, the processor 200 can be configured to calculate the state of equilibrium (SOH) when SOCi ≥ 50% in Equation 1. Here, if SOCi, which is the state of charge (SOC) at the start of discharge, is less than 50%, the processor 200 may not calculate the SOH. According to this embodiment, the problem of deterioration in the accuracy of SOH calculation during the discharge process due to performing discharge in an excessively low SOC range can be prevented. Furthermore, in this embodiment, the lower limit of 50% for SOCi can be set differently depending on the specifications of the battery cell 1 or the operating method of the battery system.

[0135] According to this configuration, SOH is calculated separately for the charging and discharging processes, and in particular, the preconditions for calculating SOH can be set differently for the charging and discharging processes. In this case, depending on whether the battery cell 1 is in the charging or discharging process, SOH can be calculated under the most suitable conditions. Therefore, the accuracy and reliability of SOH calculation can be further improved.

[0136] Furthermore, an upper limit condition for the start of charging SOC or a lower limit value for the start of discharging SOC can be set together with the other common conditions mentioned above as a prerequisite for SOH calculation. For example, during charging, the processor 200 can be configured to only satisfy the absolute value of the SOC difference (SOCi) when the upper limit condition for the start of charging SOC (SOCi) is met. The SOH during charging is calculated only when both the condition that the SOC (Society of Charge) is equal to or greater than a certain level and the condition that the charging time (fi) is equal to or greater than a certain level are met. Additionally, during discharging, the processor 200 can be configured to only satisfy the absolute value of the SOC difference (SOCi) when, together with the condition of the lower limit of the discharge start SOC (SOCi), the SOC difference is met. SOH during the discharge process is calculated only when both the condition (fi) is equal to or greater than a certain level and the condition (fi) is equal to or greater than a certain level.

[0137] According to this configuration of the present disclosure, the accuracy of SOH calculation can be further improved during charging or discharging by allowing SOH to be calculated only when a more accurate SOH can be obtained.

[0138] The battery system according to this disclosure may include a battery system diagnostic device according to this disclosure. Here, the battery system may include various types of systems, such as battery modules, battery packs, battery racks, battery banks, and energy storage systems (ESS). That is, the battery system according to this disclosure may be implemented as a battery module having multiple battery cells 1 inside a module housing, or it may be implemented as a battery pack having multiple battery modules. Additionally, the battery system according to this disclosure may be implemented as a frame having multiple battery modules or battery packs configured to stack, and a battery rack housing multiple battery modules or battery packs within the frame. Alternatively, the battery system according to this disclosure may be implemented as a battery bank including multiple battery racks. Alternatively, the battery system according to this disclosure may be implemented as an energy storage system including multiple battery banks.

[0139] Figure 8 This is a flowchart illustrating, schematically, a battery system diagnostic method according to embodiments of the present disclosure. Figure 8 In this process, each step can be performed by each component of the aforementioned battery system diagnostic device.

[0140] refer to Figure 8 The battery system diagnostic method according to this disclosure is a method for diagnosing a battery system comprising a plurality of battery cells 1 having electrode terminals therein, and may include a measurement step (S110), a calculation step (S120), and a detection step (S130).

[0141] Here, step S110 can be a step of measuring the voltage or current for each of the multiple battery cells 1 included in the battery system.

[0142] Next, step S120 may be a step of calculating SOH multiple times over time for each cell 1 using the voltage or current measured in step S110.

[0143] Alternatively, step S130 can be a step of detecting the defective battery cell in the electrode terminal among multiple battery cells 1 based on the SOH of each battery cell 1 calculated multiple times in step S120.

[0144] For details of the battery system diagnostic method according to this disclosure, the features of the battery system diagnostic apparatus according to this disclosure as described above can be applied in the same or similar manner, and therefore will not be described in detail.

[0145] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various variations and modifications within the scope of this disclosure will become apparent to those skilled in the art based on such detailed description.

[0146] Figure Labels

[0147] 1: Battery cell

[0148] 10: Electrode connector

[0149] 11: Positive terminal piece; 12: Negative terminal piece

[0150] 20: Electrode assembly

[0151] 30: Bag exterior

[0152] 31: upper bag, 32: lower bag

[0153] 41: Positive lead, 42: Negative lead

[0154] 100: Individual Measurement Unit

[0155] 200: Processor

[0156] 300: Notification Unit

[0157] 400: Memory unit

Claims

1. A battery system diagnosis apparatus comprising: at least one sensor; and at least one processor configured to: obtain data including at least one of a voltage and a current of a battery cell from the at least one sensor; calculate an SOH for the battery cell a plurality of times over a period of time by using the voltage or the current of the battery cell, and compare the SOH of the battery cell with a threshold value to determine whether a defect occurs in the battery cell.

2. The battery system diagnosis apparatus according to claim 1, wherein the processor is configured to detect a disconnection defect or an incomplete contact defect of an electrode tab of the battery cell.

3. The battery system diagnosis apparatus according to claim 2, wherein, when a case where the SOH of the battery cell is equal to or less than the threshold value continues more than a first criterion number of times, the processor is configured to detect that the battery cell has the disconnection defect.

4. The battery system diagnosis apparatus according to claim 2, wherein when a number of up / down switches of the SOH of the battery cell with respect to the threshold value continues more than a second criterion number of times, the processor is configured to detect that the battery cell has the incomplete contact defect.

5. The battery system diagnosis apparatus according to claim 4, wherein the processor is configured to identify whether the number of up / down switches is increasing or decreasing.

6. The battery system diagnosis apparatus according to claim 2, wherein, the threshold value is set based on SOH values of a plurality of battery cells.

7. The battery system diagnosis apparatus according to claim 1, wherein the processor is configured to detect whether the battery cell has a defect by distinguishing between a charging process and a discharging process.

8. The battery system diagnosis apparatus according to claim 7, wherein the processor is configured to set a precondition for calculating the SOH for the battery cell so that a precondition for the charging process and a precondition for the discharging process are set differently from each other.

9. The battery system diagnostic apparatus according to claim 1, wherein the threshold value changes over the period of time.

10. The battery system diagnostic apparatus according to claim 9, wherein the threshold value is calculated by taking an average SOH of a plurality of battery cells and adding or subtracting a preset value to the average SOH of the plurality of battery cells.

11. The battery system diagnostic apparatus according to claim 10, wherein the preset value is a value of an SOH of a battery cell corresponding to at least three standard deviations from the average SOH of the plurality of battery cells.

12. The battery system diagnostic apparatus according to claim 1, wherein when a change amount of the calculated SOH is greater than a criterion change amount for more than a predetermined number of times, the processor is configured to detect that the battery cell has the incomplete contact defect.

13. The battery system diagnostic apparatus according to claim 5, wherein the processor is configured to detect whether an electrode tab is progressing from a normal state to an incomplete contact defect state or from the incomplete contact defect state to a disconnection defect state based on whether the number of up / down switches increases over time.

14. A battery system including the battery system diagnosis apparatus according to any one of claims 1 to 13.

15. A battery system diagnosis method comprising: obtaining data including at least one of a voltage and a current of a battery cell; calculating an SOH for the battery cell a plurality of times over time by using the battery cell voltage or current obtained in the obtaining step; and and The SOH of the battery cell is compared with a threshold value to determine whether a defect has occurred in the battery cell.

16. The battery system diagnostic method according to claim 15, wherein The threshold value is changed over a period of time.

17. The battery system diagnostic method of claim 16 wherein, The threshold value is calculated by taking an average SOH of a plurality of battery cells and adding or subtracting a preset value to the average SOH of the plurality of battery cells.

18. The battery system diagnostic method of claim 17 wherein, The preset value is a value corresponding to an SOH of a battery cell that is at least three standard deviations away from the average SOH of the plurality of battery cells.

19. The battery system diagnostic method of claim 15 wherein, When the calculated amount of change in SOH is greater than a criterion amount of change for more than a predetermined number of times, it is detected that the battery cell has an incomplete contact defect.

20. The battery system diagnosis method according to claim 15, further comprising detecting whether an electrode tab is progressing from a normal state to an incomplete contact defect state or from the incomplete contact defect state to a disconnection defect state based on whether the number of up / down switches increases over time.

Images