Battery system diagnostic apparatus and method

Abstract

Disclosed is a battery diagnosis technology capable of effectively diagnosing a defective battery cell among a plurality of battery cells included in a battery system at an early stage. A battery system diagnosis device diagnoses a battery system including a plurality of battery cells having electrode tabs therein, and includes a voltage measurement unit configured to measure an end voltage of each charge or discharge for each of the plurality of battery cells; and a processor configured to accumulate the end voltage of each battery cell measured by the voltage measurement unit over time, and detect a battery cell having a defect in the electrode tab among the plurality of battery cells based on a trend of the accumulated end voltage.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0007559, filed in Korea on January 19, 2021, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to battery diagnostic technology, and more specifically, to battery diagnostic technology 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, ensuring free charging and discharging, as well as extremely low discharge rates and high energy densities.

[0005] Lithium-ion secondary batteries primarily use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively. Furthermore, a lithium-ion secondary battery includes an electrode assembly containing positive and negative electrode plates coated with the positive and negative electrode active materials, respectively, with spacers inserted between them; and an external casing, which sealably houses 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 housed in a metal can, and pouch-type secondary batteries, in which the electrode components are housed in 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 3D diagram of a pouch-shaped secondary battery.

[0009] like Figure 1 and Figure 2 As 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 between them, 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 part S is provided on the outer peripheral surface of the upper bag 31 and the lower bag 32, such that the sealing parts 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—i.e., 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 electrode terminals for electrical connection to external configurations of the secondary battery—such as another secondary battery or an external device.

[0012] With the expansion of applications for rechargeable batteries, in recent years they have been widely used not only in small devices such as portable electronic devices, but also in medium and large devices such as vehicles and energy storage systems (ESS) for driving or energy storage. In the case of such medium and 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 can include multiple battery racks, and each battery rack can be configured to house multiple battery modules within the rack frame. In addition, each battery module can include several rechargeable batteries, and each rechargeable battery can be referred to as a battery cell. Therefore, an energy storage system can 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, diagnosing the condition of specific cells and detecting defective ones becomes challenging. Furthermore, individual cells can exhibit many different types of failures. For example, various problems can occur within a cell, such as external damage, separator damage, the formation of metallic foreign objects, electrolyte leakage, and terminal defects. Terminal defects can occur when at least one positive terminal 11 or negative terminal 12—i.e., electrode terminal 10—located inside the cell breaks or causes a contact error. If such a terminal defect occurs, the performance of the corresponding cell may deteriorate or fail, and consequently, the overall performance and reliability of the battery system may deteriorate. Additionally, if a problem such as a terminal defect occurs in a specific cell, that cell may ignite and cause the entire battery system to catch fire.

[0014] Therefore, it is crucial to identify which of the numerous individual cells in a battery system is problematic and what type of defect has occurred. In particular, early diagnosis of a defective cell is essential when it occurs. However, no effective method has yet been proposed for diagnosing such defective cells, or even for the early diagnosis of specific defect types. Summary of the Invention

[0015] Technical issues

[0016] This disclosure is designed to address the problems of related technologies. Therefore, this disclosure aims to provide a battery system diagnostic apparatus and method that can effectively diagnose defective battery cells among a plurality of battery cells included in a battery system at an early stage; and 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 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 manner 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 voltage measuring unit configured to measure the end voltage of each of the plurality of battery cells for each charge or discharge cycle; and a processor configured to accumulate the end voltage of each battery cell measured by the voltage measuring unit over time, and to detect, based on the accumulated end voltage trend, 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 separately detect disconnection defects and incomplete contact defects as defects of electrode terminals.

[0021] Additionally, the processor can be configured to obtain the deviation trend between the end voltage trend and the reference trend, and based on the obtained deviation trend, detect whether each cell has defects in the electrode terminals.

[0022] Additionally, the processor can be configured to obtain an average trend of the end voltage of the multiple battery cells included in the battery system as a reference trend, and compare the reference trend with the end voltage trend.

[0023] Additionally, when the deviation trend is equal to or greater than the standard deviation, the processor can be configured to detect a disconnection defect in the corresponding battery cell.

[0024] In addition, when the deviation trend is equal to or greater than the standard deviation and the deviation trend is equal to or less than the standard deviation, the processor can be configured to detect incomplete contact defects in the corresponding battery cell.

[0025] In addition, the standard deviation can include the first standard deviation and the second standard deviation.

[0026] Additionally, the processor can be configured to detect defective battery cells by distinguishing between the charging and discharging processes for each individual cell.

[0027] In another aspect of the invention, a battery system including a battery system diagnostic device according to the present disclosure is also provided.

[0028] In another aspect of this disclosure, a battery system diagnostic method is also provided, the method diagnosing a battery system comprising a plurality of battery cells having electrode terminals, the method comprising: measuring the end voltage of each of the plurality of battery cells for each charge or discharge; accumulating the end voltage of each battery cell measured in the measurement step over time to form an end voltage trend; and detecting, based on the end voltage trend formed in the formation step, a battery cell among the plurality of battery cells that has defects in its 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 categorized.

[0033] Therefore, according to embodiments of this disclosure, appropriate follow-up measures, such as separation, repair, or 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 the 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 is readily understood by those skilled in the art will not be described in detail with respect to the components. Attached Figure Description

[0036] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

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

[0038] Figure 2 It is shown Figure 1 A 3D diagram 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 charging end voltage trend of a plurality of battery cells obtained by the processor according to an embodiment of the present disclosure.

[0041] Figure 5 It is a graph showing the discharge end voltage trend of a plurality of battery cells obtained by the processor according to an embodiment of the present disclosure.

[0042] Figure 6 This is a graph illustrating an example of a deviation trend obtained according to embodiments of the present disclosure.

[0043] Figure 7 It is a graph showing the deviation trend and standard deviation of a specific battery cell according to an embodiment of the present disclosure.

[0044] Figure 8 This is a graph showing the deviation trend and standard deviation of a specific battery cell according to another embodiment of the present disclosure.

[0045] Figure 9 This is a graph showing the deviation trend and standard deviation of a specific battery cell according to yet another embodiment of the present disclosure.

[0046] Figure 10 This is a flowchart schematically illustrating a battery system diagnostic method according to an embodiment of the present disclosure. Detailed Implementation

[0047] 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 as being interpreted based on the meaning and concepts corresponding to the technical aspects of the present disclosure, on the basis of allowing the inventors to properly define the terminology for the best interpretation.

[0048] Therefore, the descriptions presented herein are preferred examples for illustrative purposes only and are 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.

[0049] 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.

[0050] 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 a pouch-type secondary battery, wherein the electrode assembly 20 is housed in the outer pouch 30, as shown. Figure 1 and 2 As shown, the secondary battery can also be a can-type secondary battery, wherein 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 device of this disclosure, can be selected from various secondary batteries known at the filing date of this application.

[0051] 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.

[0052] A battery system may include multiple such secondary batteries (cell batteries). That is, a battery system is a system comprising multiple battery cells 1, and can refer to a system configured to charge and discharge a power source. 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.

[0053] 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 10 as described above.

[0054] In particular, the battery system diagnostic device according to this disclosure may include a voltage measurement unit 100 and a processor 200.

[0055] The voltage measurement unit 100 can be configured to measure the voltage of each of the plurality of battery cells 1 included in the battery system. For example, the voltage measurement unit 100 may include a voltage sensor and can be configured to measure the voltage across the terminals of each battery cell 1 included in the battery system.

[0056] Specifically, the voltage measurement unit can be configured to measure the end voltage during each charge or discharge cycle. For example, the voltage measurement unit can be configured to measure the voltage (charge end voltage) whenever each battery cell 1 finishes charging. Additionally, the voltage measurement unit can be configured to measure the voltage (discharge end voltage) whenever each battery cell 1 finishes discharging.

[0057] The battery system diagnostic apparatus according to this disclosure can employ various voltage measuring devices or components known at the time of filing this application as the voltage measuring unit of this disclosure. Therefore, the specific configuration of the voltage measuring unit will not be described in detail.

[0058] The processor 200 can be electrically connected to the voltage measurement unit to receive measurement data from the voltage measurement unit. In particular, since the voltage measurement unit can measure the charge / discharge end voltage (charge end voltage and / or discharge end voltage) of each of the plurality of battery cells 1, the processor 200 can receive information from the voltage measurement unit about the voltage measured for each battery cell 1 in this manner.

[0059] Additionally, the processor 200 can be configured to accumulate the end voltage of each battery cell 1 transmitted in this manner over time. The processor 200 can obtain a charge / discharge end voltage trend based on this accumulation. Here, the charge / discharge end voltage trend can be data continuously indicating the daily acquired charge / discharge end voltages in the form of a graph. For example, for each battery cell 1, the processor 200 can record each charge end voltage measured periodically or irregularly and display it as a point, connecting these points to obtain a line for each battery cell. In this case, the line obtained for each battery cell can be the end voltage trend line for the corresponding battery cell.

[0060] Figure 4 It is a graph showing the charging end voltage trend of a plurality of battery cells 1 obtained by the processor 200 according to an embodiment of the present disclosure, and Figure 5This is a discharge end voltage trend curve of multiple battery cells 1 obtained by the processor 200 according to an embodiment of the present invention.

[0061] First, refer to Figure 4 The end-of-charge voltage (EOC; end of charging) measured over a specific period (March to April) is displayed as a point for each date (time). Additionally, reference... Figure 5 The discharge end voltage (EOD) measured over a specific period (March to April) is displayed as a point for each date (time). Furthermore, by connecting the end voltage points obtained for each individual battery cell, the end voltage trend for each battery cell can be obtained.

[0062] If the charge / discharge end voltage of each battery cell 1 is measured and transmitted from the voltage measurement unit, the processor 200 can accumulate the transmitted values ​​to generate a voltage measurement unit such as... Figure 4 The charging end voltage trend line shown or as shown Figure 5 The discharge termination voltage trend line is shown.

[0063] Additionally, the processor 200 can be configured to detect which of the multiple battery cells 1 included in the battery system is defective based on the charge termination voltage trend and / or discharge termination voltage trend generated as described above. Specifically, the processor 200 can be configured to detect battery cells 1 with defects in the electrode terminals 10 based on the termination voltage trend obtained 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 terminal 10.

[0064] According to this configuration of the present disclosure, defective battery cells 1 can be diagnosed early and easily using the charge / discharge termination voltage of each battery cell 1. In particular, according to this configuration, battery cells 1 with defects in the electrode terminals 10 can be detected quickly. Therefore, problems caused by defects in the electrode terminals 10, such as overall performance degradation, malfunction, or fire of the battery system, can be effectively prevented.

[0065] 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 execute the various control logics performed in this disclosure, or these terms may be used to refer to them. Alternatively, when the control logic is implemented in software, processor 200 may be implemented as a collection of program modules. In this case, the program modules may be stored in internal memory or external memory, etc., and executed by processor 200.

[0066] In particular, if a control device, referred to as a microcontroller unit (MCU) or battery management system (BMS), is included in the battery system, the processor 200 may be implemented by a component such as the provided MCU or BMS.

[0067] Additionally, in this specification, terms such as “for” or “configured to” used for the operation or function of the processor 200 may include the meaning of “programmed to”.

[0068] In addition, the battery system diagnostic device according to this disclosure may also include, for example: Figure 3 The notification unit 300 shown.

[0069] The notification unit 300 can be configured to transmit the detection results of the processor 200 to a user, etc. 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. Specifically, the notification unit 300 can be configured to transmit information to the user about which of the plurality of battery cells 1 included in the battery system has a defect in the electrode terminals, such as identification information or location information of the defective battery cell 1. Furthermore, the notification unit 300 can be connected to various wired or wireless communication networks known at 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 transmit defective cell detection information to a portable terminal or server via a communication network.

[0070] Additionally, the battery system diagnostic device according to this disclosure may also include, for example: Figure 3 The storage unit 400 shown.

[0071] Storage unit 400 may store programs and data required for voltage measurement unit 100 or processor 200 to perform their functions. That is, storage 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 operations and functions. For example, storage unit 400 may store multiple end voltages measured for each battery cell 1 each time.

[0072] The storage unit 400 can employ any information storage device known in the art capable of writing, erasing, updating, and reading data, without limitation. As examples, the information storage device may include RAM, flash memory, ROM, EEPROM, registers, etc. Furthermore, the storage unit 400 may store program code defining procedures that can be executed by the voltage measurement unit 100 and / or the processor 200.

[0073] The charging / discharging end voltage can be the voltage after a certain rest period following the end of charging / discharging.

[0074] For example, the charging end voltage can be the open-circuit voltage (OCV) measured after a given predetermined pause time following the completion of the charging process for each battery cell 1. Similarly, the discharging end voltage can be the open-circuit voltage (OCV) measured after a given predetermined pause time following the completion of the discharging process for each battery cell 1.

[0075] According to this configuration of the present disclosure, defective cells can be detected more effectively. In particular, given the same rest period after charging or discharging, abnormally degraded cells may not be able to fully recover their voltage compared to other cells. Therefore, by comparing the voltage measured after a given predetermined rest period, degraded cells and normal cells can be more clearly distinguished.

[0076] The processor 200 can be configured to separately detect whether the defect of the electrode terminals is a disconnection defect or an incomplete contact defect. Here, a disconnection defect can mean that one or more electrode terminals 10 included in the battery cell 1 are completely cut off at a specific location. For example, in a battery cell 1 including ten electrode terminals 10, a disconnection defect can mean that at least one electrode terminal 10 is completely cut off. An incomplete contact defect can mean that one or more electrode terminals 10 included in the battery cell 1 are cut off at a specific location and then repeatedly contact each other. For example, an incomplete contact defect can mean that there is a cut portion in at least one electrode terminal 10, but intermittent contact occurs at the cut portion.

[0077] According to this configuration of the present disclosure, the trend of the charge / discharge end voltage is used to detect electrode terminal defects in the battery cell 1, and the type of electrode terminal defect can even be diagnosed separately. Therefore, in this case, more appropriate measures can be taken according to the type of electrode terminal defect.

[0078] In particular, since incomplete contact defects are a state of repeated attachment and separation of the cut portion of the electrode terminal 10, it is predictable that physical external forces will be applied to the electrode terminal 10 or the battery cell 1. Therefore, in this case, more appropriate measures can be taken relative to the external force applied to the corresponding battery cell 1. For example, when a battery cell 1 with incomplete contact defects exists, the corresponding situation can be transmitted 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 increasing the fixing force of the frame.

[0079] The processor 200 can be configured to compare the end voltage trend of each battery cell 1 with a reference trend. Here, the reference trend can be pre-calculated or stored data for comparison with the actual end voltage trend. Additionally, the processor 200 can be configured to obtain a deviation trend by using the deviation between the end voltage trend and the reference trend. This will reference... Figure 6 To describe in more detail.

[0080] Figure 6 This is a graph illustrating an example of a deviation trend obtained according to embodiments of the present disclosure.

[0081] refer to Figure 6 The end voltage trend of a specific battery cell 1 is indicated by A1, and the reference trend is indicated by B1. Additionally, the deviation trend obtained by comparing the end voltage trend A1 with the reference trend B1 is indicated by C1. The deviation trend C1 can be considered as data for a specific battery cell 1—that is, battery cell 1 whose end voltage trend is measured as A1.

[0082] Specifically, the deviation trend C1 can be obtained by the difference between the termination voltage trend A1 and the reference trend B1, and as... Figure 6 As shown, it can be represented in sigma terms. That is, the deviation trend C1 of a specific battery cell 1 can be represented to show how much the ending voltage trend A1 of the corresponding battery cell 1 differs from the reference trend B1.

[0083] As an example, the deviation trend C1 can be obtained as follows. For instance, suppose that on a specific date, the average voltage of all battery cells in the battery system is Vm in the B1 curve, the standard deviation of the voltage of all cells is Vs, and the voltage of the battery cell corresponding to the date in the A1 curve is V1. In this case, the deviation trend C1 for the corresponding date can be obtained as follows.

[0084] C1=(Vm-V1) / Vs

[0085] In other words, the deviation trend C1 of a specific cell can be calculated by subtracting the voltage value A1 of the corresponding cell from the overall average voltage value B1 and dividing it by the overall standard deviation.

[0086] Furthermore, the deviation trend C1 can be displayed in various other forms. For example, the deviation trend C1 can be displayed as a value representing the voltage difference between the end voltage trend A1 and the reference trend B1. In this case, the unit of the deviation trend C1 can be expressed as mV, etc. The deviation trend C1 can also be represented in various other forms indicating the difference between the end voltage trend A1 and the reference trend B1, and the present invention is not limited to a specific form or unit of the deviation trend.

[0087] If the deviation trend is obtained as described above, the processor 200 can be configured to detect whether the electrode terminals of the battery cell 1 are defective based on the obtained deviation trend. That is, if the deviation trend obtained for a specific battery cell 1 is as follows... Figure 6 As indicated by C1, the processor 200 can diagnose whether the electrode terminals of the corresponding battery cell 1 are defective based on the size or shape of the deviation trend C1.

[0088] The processor 200 can be configured to obtain the deviation trend of all battery cells 1 included in the battery system. Alternatively, the processor 200 can be configured to obtain the deviation trend of some battery cells 1 included in the battery system.

[0089] For example, processor 200 can be configured to obtain the deviation trend only for battery cells 1 included in the battery system whose ending voltage trend is less than or equal to a standard value. Alternatively, processor 200 can be configured to obtain the deviation trend again only for cells 1 included in the battery system whose deviation trends have been previously obtained. In this case, since it is not necessary to obtain the deviation trends of all battery cells 1, the computational load of processor 200 is reduced, thereby enabling more efficient diagnosis of the battery system.

[0090] The processor 200 can be configured to obtain the average trend of the end voltages of multiple battery cells 1 included in the battery system as a reference trend. For example, if... Figure 4 As shown, there are multiple charging end voltage trend lines for multiple battery cells 1. The average value of these multiple charging end voltage trend lines can be considered as a reference trend line, such as... Figure 6 As indicated by B1 in the diagram. As a more specific example, a reference trend can be obtained by averaging the values ​​whenever the end voltage of multiple battery cells 1 is measured and then concatenating the average values ​​with each other.

[0091] If an average trend of the end voltage for multiple battery cells 1 is obtained as described above, the processor 200 can diagnose whether the electrode terminals of the corresponding battery cell 1 are defective by comparing the obtained average trend with the end voltage trend of each battery cell 1.

[0092] Furthermore, the processor 200 can determine whether the deviation trend is greater than or equal to the standard deviation. Here, the standard deviation is the value to be compared with the deviation trend and can be considered as a standard value for judging whether the deviation trend is normal. The standard deviation can be appropriately set according to the specifications or type of the battery system or battery cell 1, the operating state of the battery system, or various conditions. The standard deviation can be pre-stored in the storage unit 400 or the processor 200.

[0093] Figure 7 It is a graph showing the deviation trend and standard deviation of a specific battery cell 1 according to an embodiment of the present disclosure.

[0094] refer to Figure 7 The deviation trend obtained for a specific battery cell 1 is indicated by C2. The method for obtaining the deviation trend is as described above, and therefore will not be repeated here. Additionally, in Figure 7 In this context, the standard deviation is indicated as D2, which is the value to be compared with the deviation trend C2. The standard deviation D2 can be stored in storage unit 400, etc., and configured to be accessible by processor 200.

[0095] The processor 200 can be configured to compare the deviation trend C2 with the standard deviation D2, and if the deviation trend C2 is equal to or greater than the standard deviation D2, detect a disconnection defect in the corresponding battery cell 1. For example, in Figure 7 In this embodiment, the deviation trend C2 is formed from the point indicated by E as being higher than the standard deviation D2. Therefore, the processor 200 can diagnose that the electrode terminal of the corresponding battery cell 1 is disconnected at the point indicated by E.

[0096] According to this configuration of the present disclosure, the disconnection defect of the battery cell 1 can be easily identified by comparing the deviation trend obtained for a specific battery cell 1 with the standard deviation.

[0097] Specifically, in this embodiment, if the deviation trend is equal to or greater than the standard deviation for a predetermined period of time or longer, the processor 200 can detect that the corresponding battery cell 1 has a disconnected connector defect. For example, if the deviation trend is equal to or greater than the standard deviation for 3 days or longer, the processor 200 can diagnose that the corresponding battery cell 1 has a disconnected connector defect.

[0098] According to this configuration of the present disclosure, even when the deviation trend is temporarily equal to or greater than the standard deviation, it is possible to prevent the diagnosis of a disconnection defect in the connector. Therefore, in this case, the accuracy of the diagnosis can be further improved.

[0099] At the same time, Figure 7 In the embodiments illustrated, the standard deviation is set uniformly regardless of the date (time), but this disclosure is not limited to this form. In particular, the standard deviation can be configured to vary according to the passage of the date (time).

[0100] First, the standard deviation can be configured to gradually increase over time. As the number of uses increases, individual battery cells 1 may deteriorate. Therefore, even if there are no defective individual battery cells 1 in the electrode terminals, the deviation between individual battery cells 1 may gradually increase. Therefore, if the standard deviation is configured to gradually increase over time as in this embodiment, even if individual battery cells 1 deteriorate, defective individual battery cells 1 in the electrode terminals can be diagnosed more accurately.

[0101] Alternatively, the standard deviation can be configured to vary according to the passage of time, particularly for each season. For example, the year can be divided into four quarters (March-May, June-August, September-November, and December-February), and the standard deviation can be set differently for each quarter of this classification. Specifically, according to this classification, in countries with significant seasonal variations, the standard deviation can change seasonally. Since the battery cell 1 may exhibit variations in its terminal voltage, etc., depending on temperature changes, this can be reflected to more accurately diagnose whether the terminal block is defective.

[0102] Alternatively, the standard deviation can be configured to be set differently based on temperature. In this case, the battery system diagnostic device according to this disclosure may further include a temperature measurement unit (not shown). Therefore, if the temperature inside or around the battery system is measured by the temperature measurement unit, the measured temperature information can be transmitted to the processor 200. The processor 200 can then set the standard deviation based on the temperature information and diagnose whether the deviation trend is abnormal based on the set standard deviation. For example, the processor 200 can be configured to increase the standard deviation at higher temperatures compared to lower temperatures.

[0103] According to this configuration of the present disclosure, terminal block defects can be diagnosed more accurately by directly reflecting the temperature of the battery system.

[0104] Figure 8 This is a graph showing the deviation trend and standard deviation of a specific battery cell 1 according to another embodiment of the present disclosure. Regarding... Figure 8 The foregoing embodiments, in particular, will not be described in detail again. Figure 7 The features of the embodiments are substantially the same or similar.

[0105] refer to Figure 8The deviation trend obtained for a specific battery cell 1 is indicated by C3. Furthermore, the standard deviation is indicated by D3. Specifically, the deviation trend C3 shows a pattern of repeated increases and decreases based on the standard deviation D3. That is, in the portion indicated by F1, the deviation trend C3 is higher than the standard deviation D3, but in the portion indicated by F2, the deviation trend C3 is lower than the standard deviation D3. Additionally, in the portion indicated by F3, the deviation trend C3 is again higher than the standard deviation D3, and in the portion indicated by F4, the deviation trend C3 is again lower than the standard deviation D3. In other words, in... Figure 8 In the embodiments, it can be assumed that the cases where the deviation trend C3 is equal to or greater than the standard deviation D3 and the cases where the deviation trend C3 is equal to or less than the standard deviation D3 occur repeatedly.

[0106] If the deviation trend C3 is equal to or greater than the standard deviation D3 and the deviation trend C3 is equal to or less than the standard deviation D3 are repeated as above, then the processor 200 can be configured to detect that the corresponding battery cell 1 has an incomplete contact defect.

[0107] According to the configuration disclosed herein, by comparing the deviation trend obtained for each battery cell 1 with the standard deviation, the incomplete contact defects of the battery cell 1 can be easily identified.

[0108] In particular, if the number of times the deviation trend switches up / down relative to the standard deviation is repeated a certain number of times or more, the processor 200 can be configured to diagnose incomplete contact defects.

[0109] For example, if the number of upward / downward switchings of the deviation trend relative to the standard deviation repeats three or more times during a predetermined period—e.g., two months—the processor 200 can be configured to diagnose incomplete contact defects. See also, as an example... Figure 8 In this embodiment, it can be assumed that the deviation trend C3 switches upward / downward relative to the standard deviation D3 three times within a two-month period. In this case, since the number of upward / downward switches (three times) can be considered equal to or greater than the standard number (three times), the processor 200 can diagnose that the corresponding battery cell 1 has an incomplete contact defect. However, if the number of upward / downward switches during this period is only two, then even if there is an upward / downward switch in the deviation trend relative to the standard deviation, the processor 200 may not diagnose that the corresponding battery cell 1 has an incomplete contact defect.

[0110] According to this configuration of the present disclosure, incomplete contact defects can be diagnosed in a more sophisticated manner by additionally applying conditions on the number of switching operations.

[0111] Figure 9This is a graph showing the deviation trend and standard deviation of a specific battery cell 1 according to yet another embodiment of the present disclosure. Regarding... Figure 9 Features that are substantially the same as or similar to those in the foregoing embodiments will not be described in detail.

[0112] refer to Figure 9 The deviation trend obtained for a specific battery cell 1 is indicated by C4. Specifically, in this embodiment, there are two standard deviations. That is, the standard deviation may include a first standard deviation as indicated by D41 and a second standard deviation as indicated by D42. Here, the second standard deviation D42 can be set to be lower than the first standard deviation D41.

[0113] In this embodiment, when the deviation trend C4 is equal to or greater than the first standard deviation D41 and the deviation trend C4 is less than or equal to the second standard deviation D42 are repeated a certain number of times or more, the processor 200 can determine that the corresponding battery cell 1 has an incomplete contact defect.

[0114] In other words, Figure 9 In the case where the deviation trend C4 during the time period is greater than or equal to the first standard deviation D41, it is the same as that indicated by G1 and G3, and the deviation trend C4 is less than or equal to the second standard deviation D42, it is the same as that indicated by G2 and G4. In this case, the number of upward / downward switching of the deviation trend C4 relative to the reference deviations D41 and D42 can be considered as 3 times. In addition, the processor 200 determines whether the number of upward / downward switching is equal to or greater than the standard number (e.g., 3 times), and if the upward / downward switching repeats the standard number or more, it determines that the corresponding battery cell 1 has an incomplete contact defect.

[0115] According to this configuration, incomplete contact defects of the electrode contacts can be detected more accurately. In particular, according to this embodiment, even when the deviation trend repeatedly switches upward / downward at a level approximately similar to a reference deviation, incomplete contact problems can be prevented from being diagnosed.

[0116] Furthermore, the processor 200 can be configured to detect whether the battery cell 1 has a disconnection defect by comparing the termination voltage trend with a threshold trend. Here, the threshold trend is the value to be compared with the termination voltage trend, and can be considered as a standard value used to determine whether the termination voltage is abnormal.

[0117] For example, the threshold trend could be related to... Figure 4 or Figure 5The values ​​corresponding to 3 sigma or 6 sigma obtained from the multiple end voltage data shown are presented. Specifically, the curves corresponding to 3 sigma or 6 sigma can be located at the lower and upper parts, respectively, relative to the average end voltage for the multiple cell 1. In this case, the threshold trend can be selected as the curve located in the lower part of the curve corresponding to 3 sigma or 6 sigma for the multiple end voltage data.

[0118] Additionally, if the termination voltage trend is less than or equal to the threshold trend, and especially if the termination voltage trend is less than or equal to the threshold trend for a predetermined time or more, the processor 200 can be configured to detect that the corresponding battery cell 1 has a disconnection defect.

[0119] Additionally, the processor 200 can be configured to compare the end voltage trend with the threshold trend, and if the number of upward / downward switching of the end voltage trend relative to the threshold trend continues for a standard number of times or more, then the corresponding battery cell 1 is detected to have an incomplete contact defect.

[0120] Furthermore, when a defective battery cell 1 is detected, the processor 200 can be configured to perform a charging and discharging process separately for each battery cell 1.

[0121] For example, for each battery cell 1, the processor 200 can be configured to process the end voltage trend obtained during charging and the end voltage trend obtained during discharging separately. In this case, the aforementioned reference trends or deviation trends can also be processed, managed, and / or stored separately for the charging and discharging processes. For example, the reference trends for charging and the reference trends for discharging can be stored separately in the storage unit 400 and accessed by the processor 200.

[0122] 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. In particular, the pattern of the terminal voltage of the battery cell 1 can vary depending on whether it is in a charging or discharging state, and according to this embodiment, voltage trends 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.

[0123] 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 within 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 configured to stack multiple battery modules or battery packs, 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.

[0124] Figure 10 This is a schematic diagram illustrating a flowchart of a battery system diagnostic method according to an embodiment of the present disclosure. Figure 10 In this process, each step can be performed by each component of the aforementioned battery system diagnostic device.

[0125] refer to Figure 10 The battery system diagnostic method according to this disclosure is a method for diagnosing a battery system including multiple battery cells having electrode terminals, and may include an end voltage measurement step (S110), an end voltage trend formation step (S120), and a defective cell detection step (S130).

[0126] First, in step S110, for each of the multiple battery cells, the end voltage can be measured for each charge or discharge cycle.

[0127] Next, in step S120, an end voltage trend can be formed by accumulating the end voltage of each battery cell measured in step S110 over time.

[0128] Furthermore, in step S130, a battery cell with a defect in the electrode terminals can be detected among the multiple battery cells based on the end voltage trend formed in step S120.

[0129] For details of the battery system diagnostic method according to this disclosure, the features of the battery system diagnostic device according to the present invention as described above can be applied in the same or similar manner, and therefore will not be repeated here.

[0130] This disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of this disclosure, 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 this detailed description.

[0131] Figure Labels

[0132] 1: Battery cell

[0133] 10: Connector

[0134] 11: Positive terminal piece; 12: Negative terminal piece

[0135] 20: Electrode assembly

[0136] 30: Bag exterior

[0137] 31: upper bag, 32: lower bag

[0138] 41: Positive lead, 42: Negative lead

[0139] 100: Voltage Measurement Unit

[0140] 200: Processor

[0141] 300: Notification Unit

[0142] 400: Storage unit

Claims

1. A battery system diagnostic device, said battery system diagnostic device diagnosing a battery system comprising a plurality of battery cells having electrode terminals, said device comprising: A voltage measurement unit configured to measure the end voltage of each charge or discharge cycle for each of a plurality of battery cells; as well as A processor configured to accumulate the end voltage of each battery cell measured by the voltage measurement unit over time, and to detect, based on the accumulated end voltage trend, battery cells among the plurality of battery cells that have defects in the electrode terminals.

2. The battery system diagnostic device according to claim 1, in, The processor is configured to separately detect disconnection defects and incomplete contact defects as defects of the electrode terminals.

3. The battery system diagnostic device according to claim 1, in, The processor is configured to obtain the deviation trend between the end voltage trend and the reference trend, and to detect whether each battery cell has a defect in the electrode terminal based on the obtained deviation trend.

4. The battery system diagnostic device according to claim 3, in, The processor is configured to obtain an average trend of the end voltage of the plurality of battery cells included in the battery system as the reference trend, and to compare the reference trend with the end voltage trend.

5. The battery system diagnostic device according to claim 3, in, When the deviation trend is equal to or greater than the standard deviation, the processor is configured to detect a disconnection defect in the corresponding battery cell.

6. The battery system diagnostic device according to claim 3, in, When the deviation trend is equal to or greater than the standard deviation and the deviation trend is equal to or less than the standard deviation, the processor is configured to detect that the corresponding battery cell has an incomplete contact defect.

7. The battery system diagnostic device according to claim 6, in, The standard deviation includes a first standard deviation and a second standard deviation.

8. The battery system diagnostic device according to claim 1, in, The processor is configured to detect defective battery cells by distinguishing between the charging and discharging processes for each individual battery cell.

9. A battery system comprising a battery system diagnostic apparatus according to any one of claims 1 to 8.

10. A battery system diagnostic method, the battery system diagnostic method diagnosing a battery system comprising a plurality of battery cells having electrode terminals, the method comprising: For each of the plurality of battery cells, the end voltage of each charge or discharge is measured; The termination voltage of each battery cell measured in the measurement step is accumulated over time to form a termination voltage trend; as well as Based on the end voltage trend formed in the formation step, detect the battery cells with defects in the electrode terminals among the plurality of battery cells.

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