Battery management device and method of operation thereof

Abstract

A battery management device according to one embodiment disclosed in this document may include an information acquisition unit that acquires open circuit voltages of a plurality of battery cells, and a controller that calculates a first voltage of each of the plurality of battery cells relating to a change in the open circuit voltage of the plurality of battery cells over a predetermined time period, calculates a second voltage that is an average of the first voltages of each of the plurality of battery cells, calculates a deviation based on the first voltage and the second voltage of each of the plurality of battery cells, and diagnoses the plurality of battery cells based on the ratio of the first voltage to the second voltage of each of the plurality of battery cells and the deviation.

Description

[Technical Field]

[0001] The present invention claims the benefit of priority based on Korean Patent Application Nos. 10-2022-0151067, filed November 11, 2022, and 10-2022-0151066, filed November 11, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. SUMMARY OF THE INVENTION The embodiments disclosed herein relate to a battery management device and method of operation. [Background technology]

[0002] In recent years, research and development into secondary batteries has been actively pursued. Here, secondary batteries are batteries that can be charged and discharged, and include both conventional Ni / Cd batteries, Ni / MH batteries, and more recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni / Cd batteries, Ni / MH batteries, and other batteries. Furthermore, because lithium-ion batteries can be manufactured to be compact and lightweight, they are used as power sources for mobile devices. In recent years, their range of use has expanded to include power sources for electric vehicles, and they are attracting attention as a next-generation energy storage medium.

[0003] Batteries used in vehicles or ESS (Energy Storage Systems) can pose a major risk if they catch fire during use. If an internal short circuit in a battery becomes severe, it can lead to thermal runaway and cause a fire. One cause of an internal short circuit is lithium deposition on the surface of the battery's negative electrode. In a normal battery, lithium ions released from the positive electrode are reduced into the negative electrode during charging. However, in a defective battery, some lithium ions are deposited in the form of lithium metal from the surface of the negative electrode. If the deposited lithium continues to grow through repeated charging, it can come into contact with the positive electrode or positive electrode current collector, causing an internal short circuit. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the embodiments disclosed herein is to provide a battery management device and an operating method thereof that can diagnose disconnection of tabs of multiple battery cells.

[0005] One objective of the embodiments disclosed in this document is to provide a battery management device and an operating method thereof that can diagnose the state of multiple battery cells based on the voltages of the multiple battery cells during a rest period after charging and discharging.

[0006] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] A battery management device according to one embodiment disclosed in this document may include an information acquisition unit that acquires open circuit voltages of a plurality of battery cells, and a controller that calculates a first voltage of each of the plurality of battery cells relating to a change in the open circuit voltage of the plurality of battery cells over a predetermined time period, calculates a second voltage that is an average of the first voltages of each of the plurality of battery cells, calculates a deviation based on the first voltage and the second voltage of each of the plurality of battery cells, and diagnoses the plurality of battery cells based on the ratio of the first voltage to the second voltage of each of the plurality of battery cells and the deviation.

[0008] In one embodiment, the controller can diagnose the plurality of battery cells a plurality of times, and finally diagnose the battery cells that have been diagnosed a set number of times or more as defective battery cells.

[0009] In one embodiment, the controller may diagnose the plurality of battery cells after discharging the plurality of battery cells multiple times.

[0010] In one embodiment, the controller may diagnose, as a defective battery cell, a battery cell among the plurality of battery cells, in which a ratio of a first voltage to the second voltage is not within a preset range. In one embodiment, the first voltage may be an open circuit voltage value that is restored after use of the battery cell.

[0011] In one embodiment, the information acquisition unit can acquire open circuit voltages of the plurality of battery cells after a preset time has elapsed since the charging or discharging of the plurality of battery cells.

[0012] In one embodiment, the controller can diagnose as a defective battery cell any battery cell among the plurality of battery cells in which the ratio of the first voltage to the second voltage is not within a preset range and the deviation between the first voltage and the second voltage is equal to or greater than a preset value.

[0013] In one embodiment, the controller may finally diagnose a battery cell as defective if the battery cell is diagnosed a set number of times in succession as having the ratio outside a preset range and the second voltage deviation greater than or equal to a set value.

[0014] In one embodiment, when a change in the open circuit voltage of one of the plurality of battery cells is equal to or greater than a threshold, the controller can determine that the change is noise without performing a diagnosis.

[0015] In one embodiment, the controller can define a ranking of each of the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells, and diagnose the plurality of battery cells based on the ranking of each of the plurality of battery cells.

[0016] In one embodiment, the controller determines, among the plurality of battery cells, a first battery cell having the largest ratio of the first voltage to the second voltage, a second battery cell having the second largest ratio, and a third battery cell having the smallest ratio, calculates a first difference that is the difference between the ratio of the first battery cell and the ratio of the second battery cell, calculates a second difference that is the difference between the ratio of the second battery cell and the ratio of the third battery cell, and can diagnose the state of the first battery cell based on the ratio of the first battery cell, the first difference, and the second difference.

[0017] In one embodiment, the controller can diagnose as a faulty battery cell a battery cell in which the ratio of the first battery cell is equal to or greater than a first threshold, the ratio of the first difference to the second difference is equal to or greater than a second threshold, and the deviation is equal to or greater than a set value.

[0018] An operating method of a battery management device according to one embodiment disclosed in this document may include the steps of acquiring open circuit voltages of a plurality of battery cells, calculating a first voltage of each of the plurality of battery cells relating to a change in the open circuit voltage of the plurality of battery cells over a predetermined time period, calculating a second voltage that is an average of the first voltages of each of the plurality of battery cells, calculating a deviation based on the first voltage and the second voltage of each of the plurality of battery cells, and diagnosing the plurality of battery cells based on the ratio of the first voltage to the second voltage of each of the plurality of battery cells and the deviation.

[0019] In one embodiment, the step of diagnosing the plurality of battery cells based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells may include the steps of diagnosing the plurality of battery cells multiple times, and finally diagnosing the battery cells that have been diagnosed a set number of times or more as defective battery cells.

[0020] In one embodiment, the step of diagnosing the plurality of battery cells a plurality of times may include diagnosing the plurality of battery cells for each discharge after the plurality of battery cells are discharged a plurality of times.

[0021] In one embodiment, the step of diagnosing the plurality of battery cells based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells may diagnose, as a defective battery cell, any battery cell among the plurality of battery cells whose ratio between the first voltage and the second voltage is not within a predetermined range.

[0022] In one embodiment, the step of acquiring the open circuit voltages of the plurality of battery cells can acquire the open circuit voltages of the plurality of battery cells after a predetermined time has elapsed since the charging or discharging of the plurality of battery cells.

[0023] In one embodiment, the method may further include the steps of: defining a ranking of each of the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells; and diagnosing the plurality of battery cells based on the ranking of each of the plurality of battery cells.

[0024] In one embodiment, the step of diagnosing the plurality of battery cells based on the ranking of each of the plurality of battery cells may include the steps of determining a first battery cell having the highest ratio of the first voltage to the second voltage, a second battery cell having the second highest ratio, and a third battery cell having the lowest ratio among the plurality of battery cells; calculating a first difference that is the difference between the ratio of the first battery cell and the ratio of the second battery cell; calculating a second difference that is the difference between the ratio of the second battery cell and the ratio of the third battery cell; and diagnosing the state of the first battery cell based on the ratio of the first battery cell, the first difference, and the second difference. [Effects of the Invention]

[0025] A battery management device and its operating method according to an embodiment disclosed herein can accurately diagnose disconnection of tabs of multiple battery cells. A battery management device and its operating method according to one embodiment disclosed in this document can diagnose the state of multiple battery cells by calculating the voltage change of each battery cell based on the voltage of the multiple battery cells during a rest period after charging and discharging.

[0026] A battery management device and its operating method according to one embodiment disclosed in this document can diagnose a broken tab of at least one battery cell among a plurality of battery cells based on the ratio of the open circuit voltage change of the plurality of battery cells to the average of the open circuit voltage change.

[0027] A battery management device and its operating method according to one embodiment disclosed in this document can diagnose whether the tab of at least one of a plurality of battery cells is broken based on the ranking of the ratio between the voltage change of the plurality of battery cells and the average voltage change. In addition, this document can provide various other benefits that can be perceived directly or indirectly. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a block diagram showing the configuration of a typical battery pack. [Figure 2] 1 is a block diagram illustrating a battery management device according to one embodiment disclosed herein. [Figure 3] FIG. 1 is a diagram illustrating an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. [Figure 4a] FIG. 1 is a diagram illustrating an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. [Figure 4b] FIG. 1 is a diagram illustrating an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. [Figure 4c] FIG. 1 is a diagram illustrating an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. [Figure 5] 1 is a flowchart illustrating a method of operation of a battery management device according to one embodiment disclosed herein. [Figure 6] 1 is a flowchart illustrating a method of operating a battery management device according to an embodiment disclosed herein. [Figure 7] 10 is a flowchart illustrating a method of operating a battery management device according to another embodiment disclosed herein. [Figure 8] 10 is a flowchart illustrating a method of operating a battery management device according to another embodiment disclosed herein. [Figure 9] FIG. 1 is a block diagram illustrating a hardware configuration of a computing system for performing an operation method of a battery management device according to an embodiment disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, the embodiments disclosed herein will be described in detail with reference to the exemplary drawings. When assigning reference numerals to components in each drawing, it should be noted that the same reference numerals are assigned to the same components when they appear in other drawings as much as possible. Furthermore, when describing the embodiments disclosed herein, if a detailed description of related known structures or functions is deemed to hinder understanding of the embodiments disclosed herein, such detailed description will be omitted.

[0030] In describing components of the embodiments disclosed herein, terms such as first, second, A, B, (a), (b), etc. may be used. Such terms are merely used to distinguish the component from other components and do not limit the nature, order, or sequence of the components. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed herein belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0031] FIG. 1 is a block diagram showing the configuration of a typical battery pack. Referring to FIG. 1, a battery control system including a battery pack 1 according to an embodiment of the present invention and a host controller 2 included in the host system is schematically shown.

[0032] 1, the battery pack 1 includes a plurality of battery cells 10, each of which is made up of one or more battery cells and is capable of being charged and discharged, a switching unit 14 connected in series to the (+) terminal side or (-) terminal side of the plurality of battery cells 10 for controlling the flow of charge and discharge current of the plurality of battery cells 10, and a battery management system (BMS) 20 that monitors the voltage, current, temperature, etc. of the battery pack 1 and controls and manages the battery pack 1 to prevent overcharging, overdischarging, etc. In this case, the battery pack 1 may be provided with a plurality of the plurality of battery cells 10, sensors 12, switching units 14, and battery management systems 20.

[0033] Here, the switching unit 14 is an element for controlling the flow of current for charging or discharging the multiple battery cells 10, and may be, for example, at least one relay, electromagnetic contactor, or the like, depending on the specifications of the battery pack 1.

[0034] The battery management system 20 is an interface that receives input of measured values ​​of the various parameters described above, and may include a plurality of terminals and circuits connected to the terminals and processing the received values. The battery management system 20 may also control the ON / OFF of a switching unit 14, such as a relay or contactor, and may be connected to a plurality of battery cells 10 to monitor the status of each of the plurality of battery cells 10. According to an embodiment, the battery management system 20 may include the battery management device 100 of FIG. 2. According to another embodiment, the battery management system 20 may be a system different from the battery management device 100 of FIG. 2. That is, the battery management device 100 of FIG. 2 may be included in the battery pack 1, or may be configured as a separate device external to the battery pack 1.

[0035] The upper controller 2 can transmit control signals for the plurality of battery cells 10 to the battery management system 20. As a result, the operation of the battery management system 20 can be controlled based on the signals applied from the upper controller 2.

[0036] FIG. 2 is a block diagram illustrating a battery management device according to one embodiment disclosed herein. Referring to FIG. 2, a battery management device 100 according to an embodiment disclosed herein may include an information acquisition unit 110 and a controller 120.

[0037] According to an embodiment, the battery management device 100 may be included in the battery management system 20 of Fig. 1. According to another embodiment, the battery management device 100 may be included in the upper controller 2 of Fig. 1. According to yet another embodiment, the battery management device 100 may be included in a separate device not shown in the battery pack 1 of Fig. 1.

[0038] The information acquiring unit 110 can acquire the open circuit voltages of the plurality of battery cells. For example, the information acquiring unit 110 can acquire the open circuit voltages of the plurality of battery cells in chronological order.

[0039] According to an embodiment, the information acquisition unit 110 may acquire the voltages of the battery cells during a rest period after a predetermined time has elapsed since the charging or discharging of the battery cells. During the rest period, a battery cell with a disconnected tab may experience a faster and larger voltage change than a normal battery cell, so the information acquisition unit 110 may acquire the voltages of the battery cells during the rest period.

[0040] According to the embodiment, the information acquisition unit 110 can acquire the open circuit voltages of the plurality of battery cells after a preset time has elapsed since the charging or discharging of the plurality of battery cells.

[0041] The controller 120 can calculate a first voltage of each of the plurality of battery cells, which is a change in the open circuit voltage of each of the plurality of battery cells corresponding to two different times. For example, the controller 120 can calculate the difference between the open circuit voltage of the plurality of battery cells corresponding to the first time and the open circuit voltage of the plurality of battery cells corresponding to the second time, to calculate the first voltage of each of the plurality of battery cells.

[0042] The controller 120 can calculate a second voltage that is an average of the first voltages of the plurality of battery cells. For example, the second voltage may be an average of the open circuit voltage deviations of the plurality of battery cells corresponding to two different times.

[0043] The controller 120 can calculate a deviation based on the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can calculate a standard deviation of the first voltage of each of the plurality of battery cells relative to the second voltage.

[0044] The controller 120 can calculate the ratio between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can divide the first voltage of each of the plurality of battery cells by the second voltage to calculate the ratio of each of the plurality of battery cells.

[0045] The controller 120 can diagnose the plurality of battery cells based on the ratio and deviation between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can diagnose as a defective battery cell any battery cell whose ratio between the first voltage and the second voltage is outside a preset range. According to an embodiment, the controller 120 can diagnose as a defective battery cell any battery cell whose first voltage is outside a range of 0.8 to 1.2 times the second voltage.

[0046] According to an embodiment, the controller 120 may diagnose a plurality of battery cells multiple times. For example, the controller 120 may discharge a plurality of battery cells multiple times and then diagnose the plurality of battery cells for each discharge. In this case, the controller 120 may store the diagnosis results for the plurality of battery cells for each diagnosis. The controller 120 may also diagnose a battery cell that has been diagnosed a predetermined number of times or more as a defective battery cell. For example, when a plurality of battery cells are discharged 10 times, the controller 120 may diagnose the plurality of battery cells after the discharge and may diagnose a battery cell that has been diagnosed as defective seven or more times as a defective battery cell. Therefore, the battery management device 100 disclosed herein may minimize the possibility of misdiagnosis. However, the number of times a battery cell is finally diagnosed is not limited to the above values, and a user may adjust the preset number of times a battery cell is finally diagnosed via the controller 120.

[0047] According to an embodiment, the controller 120 may set two different times to be different from each other by a predetermined time interval. For example, the controller 120 may set two different times to be different from each other by 600 seconds. According to an embodiment, the first voltage may be an open circuit voltage value that is restored after use of the battery cell.

[0048] According to an embodiment, the controller 120 may diagnose, as a defective battery cell, a battery cell in which the ratio between the first voltage and the second voltage is not within a preset range and the deviation between the first voltage and the second voltage is equal to or greater than a preset value. For example, the controller 120 may finally diagnose a battery cell as defective if the battery cell is diagnosed a predetermined number of times consecutively as a battery cell in which the ratio is not within the preset range and the deviation between the second voltage is equal to or greater than a preset value. For example, the predetermined number of times may be two, but may be more to reduce errors.

[0049] According to an embodiment, if a change in the open circuit voltage of a battery cell is equal to or greater than a threshold, the controller 120 may determine the battery cell as noise without performing a diagnosis. For example, if the voltage of a battery cell changes more significantly than other battery cells or a preset threshold, the probability of the change being noise is high, and the controller 120 may perform a diagnosis excluding the value determined to be noise.

[0050] FIG. 3 is a diagram for explaining an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. Referring to FIG. 3, the information acquisition unit 110 can acquire the open circuit voltages 300 of a plurality of battery cells in time series.

[0051] The controller 120 can calculate the change in the open circuit voltage of each of the plurality of battery cells corresponding to two different times. For example, the controller 120 can calculate the change in the open circuit voltage of each of the plurality of battery cells from the difference between the voltage of the plurality of battery cells corresponding to 600 seconds and the voltage of the plurality of battery cells corresponding to 1200 seconds.

[0052] The controller 120 can calculate a second voltage, which is an average of the first voltages of the plurality of battery cells, and can diagnose the states of the plurality of battery cells based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can diagnose a battery cell whose ratio between the first voltage and the second voltage of each of the plurality of battery cells is not within a predetermined range as a defective battery cell. That is, the controller 120 can diagnose a battery cell whose open circuit voltage recovery ratio is higher or lower than the average open circuit voltage recovery ratio as a defective battery cell.

[0053] The battery management device 100 according to one embodiment disclosed in this document can accurately diagnose disconnection of the tabs of multiple battery cells. The battery management device 100 according to one embodiment disclosed in this document can calculate the voltage change of each battery cell based on the voltage of the rest period after charging and discharging of the multiple battery cells, and diagnose the state of the multiple battery cells.

[0054] The battery management device 100 according to one embodiment disclosed in this document can diagnose whether the tab of at least one of a plurality of battery cells is broken based on the ratio of the voltage change of the plurality of battery cells to the average voltage change.

[0055] 2 again, according to an embodiment, the information acquiring unit 110 may acquire the voltages of the battery cells during a rest period after a predetermined time has elapsed since the charging or discharging of the battery cells. During the rest period, a battery cell with a disconnected tab may experience a faster and larger voltage change than a normal battery cell, so the information acquiring unit 110 may acquire the voltages of the battery cells during the rest period.

[0056] The controller 120 can calculate a first voltage of each of the plurality of battery cells relating to a voltage change of each of the plurality of battery cells corresponding to two different times. For example, the controller 120 can calculate a difference between the voltage of the plurality of battery cells corresponding to the first time and the voltage of the plurality of battery cells corresponding to the second time, and calculate the first voltage of each of the plurality of battery cells.

[0057] The controller 120 can calculate a second voltage that is an average of the first voltages of the plurality of battery cells. For example, the second voltage may be an average of voltage deviations of the plurality of battery cells corresponding to two different times.

[0058] The controller 120 can calculate the ratio between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can divide the first voltage of each of the plurality of battery cells by the second voltage to calculate the ratio of each of the plurality of battery cells.

[0059] The controller 120 may define a rank for each of the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 may define a rank for each of the plurality of battery cells from first to last based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells. As another example, the controller 120 may determine a first battery cell having the highest ratio between the first voltage and the second voltage, a second battery cell having the second highest ratio, and a third battery cell having the lowest ratio between the first voltage and the second voltage of each of the plurality of battery cells.

[0060] The controller 120 can diagnose the state of the plurality of battery cells based on the rank of each of the plurality of battery cells. For example, the controller 120 can calculate a first difference, which is the difference between the ratio of a first battery cell (the ratio of the first voltage to the second voltage of the first battery cell) and the ratio of a second battery cell (the ratio of the first voltage to the second voltage of the second battery cell). The controller 120 can also calculate a second difference, which is the difference between the ratio of the second battery cell and the ratio of a third battery cell (the ratio of the first voltage to the second voltage of the third battery cell). In this case, the controller 120 can diagnose the state of the first battery cell based on the ratio of the first battery cell, the first difference, and the second difference.

[0061] According to an embodiment, the controller 120 can diagnose that a tab break has occurred in the first battery cell if the ratio of the first battery cell is greater than or equal to a first threshold and the ratio of the first difference to the second difference is greater than or equal to a second threshold.

[0062] According to an embodiment, the controller 120 may set two different times to be separated by a predetermined time. For example, the controller 120 may set two different times to be separated by a 600-second difference. As another example, the controller 120 may periodically set two different times to be separated by a predetermined time, such as 600 seconds, 1200 seconds, or 1800 seconds.

[0063] According to the embodiment, the controller 120 can diagnose the plurality of battery cells based on all of the ratio, rank, and deviation between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can diagnose the battery cell as not abnormal if any of the ratio, rank, and deviation does not meet a standard. As another example, the controller 120 can diagnose the battery cell as abnormal if any of the ratio, rank, and deviation exceeds a standard. That is, the controller 120 can diagnose the plurality of battery cells by comprehensively considering the ratio, rank, and deviation.

[0064] 4a, 4b, and 4c are diagrams for explaining an example in which a battery management device according to an embodiment disclosed herein diagnoses a plurality of battery cells. Referring to FIGS. 4a, 4b, and 4c, the information acquiring unit 110 can acquire the voltages 310 of a plurality of battery cells in time series.

[0065] The controller 120 can calculate the voltage change of each of the plurality of battery cells corresponding to two different times. For example, the controller 120 can calculate the voltage change of each of the plurality of battery cells from the difference between the voltage of each of the plurality of battery cells corresponding to 600 seconds and the voltage of each of the plurality of battery cells corresponding to 1200 seconds. The controller 120 can also calculate the voltage change of each of the plurality of battery cells from the difference between the voltage of each of the plurality of battery cells corresponding to 1200 seconds and the voltage of each of the plurality of battery cells corresponding to 1800 seconds. In other words, the controller 120 can calculate the voltage change 320 of each of the plurality of battery cells every 600 seconds.

[0066] The controller 120 can calculate a second voltage, which is an average of the first voltages of each of the plurality of battery cells, and can define the ranking of each of the plurality of battery cells based on the ratio 330 between the first voltage and the second voltage of each of the plurality of battery cells. For example, the controller 120 can determine a first battery cell with the highest ratio, a second battery cell with the second highest ratio, and a third battery cell with the lowest ratio based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells corresponding to 3600 seconds. In this case, the controller 120 can calculate a first difference, which is the difference between the ratio between the first voltage and the second voltage of the first battery cell and the ratio between the first voltage and the second voltage of the second battery cell, and a second difference, which is the difference between the ratio between the first voltage and the second voltage of the second battery cell and the ratio between the first voltage and the second voltage of the third battery cell. The controller 120 can also diagnose the state of the first battery cell based on the ratio between the first voltage and the second voltage of the first battery cell, the first difference, and the second difference.

[0067] According to the embodiment, the controller 120 may diagnose that a tab break has occurred in the first battery cell if the ratio of the first voltage to the second voltage of the first battery cell is equal to or greater than a first threshold and the ratio of the first difference to the second difference is equal to or greater than a second threshold. That is, the controller 120 may diagnose that a tab break has occurred in the first battery cell at 3600 seconds.

[0068] FIG. 5 is a flowchart illustrating a method of operating a battery management device according to one embodiment disclosed herein. According to an embodiment, the operations shown in FIG. 5 can be performed via the battery management device 100 of FIG.

[0069] In step S110, the information acquiring unit 110 can acquire the open circuit voltages of the plurality of battery cells. For example, in step S110, the information acquiring unit 110 can acquire the open circuit voltages of the plurality of battery cells after a preset time has elapsed since the charging or discharging of the plurality of battery cells.

[0070] In step S120, the controller 120 may calculate a first voltage of each of the plurality of battery cells, which is related to a change in the open circuit voltage of the plurality of battery cells during a preset time period.

[0071] In step S130, the controller 120 can calculate a second voltage that is an average of the first voltages of the plurality of battery cells. In step S140, the controller 120 can calculate a deviation based on the first voltage and the second voltage of each of the plurality of battery cells.

[0072] In step S150, the controller 120 can diagnose the plurality of battery cells based on the ratio and deviation between the first voltage and the second voltage of each of the plurality of battery cells. For example, in step S150, the controller 120 can diagnose as a defective battery cell any battery cell whose ratio between the first voltage and the second voltage is not within a preset range.

[0073] FIG. 6 is a flowchart specifically illustrating a method of operating a battery management device according to an embodiment disclosed herein. According to an embodiment, the operations shown in FIG. 6 may be performed via the battery management device 100 of FIG.

[0074] 6, in step S210, the controller 120 can diagnose the plurality of battery cells multiple times. For example, the controller 120 can diagnose the plurality of battery cells for each discharge after discharging the plurality of battery cells multiple times.

[0075] In step S220, the controller 120 can finally diagnose a battery cell that has been diagnosed a set number of times or more as a defective battery cell. According to an embodiment, steps S210 to S240 may be executed as being included in step S150 of FIG.

[0076] 7 is a diagram illustrating the operation of a battery management device according to another embodiment disclosed herein. According to an embodiment, the operation illustrated in FIG. 7 can be performed via the battery management device 100 of FIG.

[0077] Referring to FIG. 7, in step S310, the controller 120 may define a ranking for each of the plurality of battery cells based on the ratio between the first voltage and the second voltage of each of the plurality of battery cells.

[0078] In step S320, the controller 120 can diagnose each of the battery cells based on the rank of each of the battery cells. According to an embodiment, step S320 can be performed together with step S150. That is, the controller 120 can diagnose each of the battery cells based on the rank, ratio, and deviation of each of the battery cells.

[0079] 8 is a diagram specifically illustrating the operation of a battery management device according to another embodiment disclosed herein. According to an embodiment, the operation illustrated in FIG. 8 can be performed via the battery management device 100 of FIG. 2.

[0080] Referring to FIG. 8, in step S410, the controller 120 can determine, among the plurality of battery cells, the first battery cell having the largest ratio of the first voltage to the second voltage, the second battery cell having the second largest ratio, and the third battery cell having the smallest ratio.

[0081] In step S420, the controller 120 can calculate a first difference, which is the difference between the ratio of the first battery cell and the ratio of the second battery cell. In step S430, the controller 120 can calculate a second difference, which is the difference between the ratio of the second battery cell and the ratio of the third battery cell.

[0082] In step S440, the controller 120 can diagnose the state of the first battery cell based on the ratio of the first battery cell, the first difference, and the second difference. Steps S410 to S440 may be performed in conjunction with step S320 of FIG.

[0083] FIG. 9 is a block diagram showing the hardware configuration of a computing system for performing the method of operating a battery management device according to an embodiment disclosed herein.

[0084] Referring to FIG. 9, a computing system 1000 according to one embodiment disclosed in this document may include a microcontroller unit (MCU) 1010, a memory 1020, an input / output I / F 1030, and a communication I / F 1040.

[0085] The MCU 1010 may be a processor that executes various programs stored in the memory 1020 (e.g., a program for collecting voltages and currents of multiple battery cells, a program for calculating voltage changes of multiple battery cells, a program for calculating the average voltage changes of multiple battery cells, a program for diagnosing multiple battery cells, etc.), processes various information including the voltages, currents, voltage changes, average voltage changes, and whether or not tabs are broken through such programs, of multiple battery cells, and performs the functions of the controller included in the battery management device shown in FIG. 2 described above.

[0086] The memory 1020 can store various programs such as a program for collecting voltages and currents of multiple battery cells, a program for calculating voltage changes of multiple battery cells, a program for calculating the average voltage changes of multiple battery cells, a program for diagnosing multiple battery cells, etc. The memory 1020 can also store various information such as the voltages, currents, voltage changes, average voltage changes of multiple battery cells, and whether or not tabs are broken.

[0087] A plurality of such memories 1020 may be provided as necessary. The memories 1020 may be volatile memories or nonvolatile memories. As the volatile memories 1020, RAM, DRAM, SRAM, etc. may be used. As the nonvolatile memories 1020, ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc. may be used. The examples of the memories 1020 listed above are merely illustrative and are not limited to these examples.

[0088] The input / output I / F 1030 can provide an interface that connects input devices (not shown) such as a keyboard, mouse, or touch panel, and output devices such as a display (not shown), to the MCU 1010, enabling data to be sent and received.

[0089] The communication I / F 1040 is configured to be able to send and receive various data to and from a server, and may be any device capable of supporting wired or wireless communication. For example, the battery management device can send and receive information such as the voltage, current, voltage change, average voltage change, and whether or not tabs are broken from a separately provided external server via the communication I / F 1040.

[0090] In this way, the computer program according to one embodiment disclosed in this document may be recorded in memory 1020 and processed by MCU 1010 to be realized, for example, as a module that performs each function shown in FIG. 2.

[0091] The above description is merely an illustrative example of the technical ideas disclosed in this document, and various modifications and variations are possible by a person having ordinary knowledge in the technical field to which the embodiments disclosed in this document belong, without departing from the essential characteristics of the embodiments disclosed in this document.

[0092] Therefore, the embodiments disclosed in this document are intended to illustrate, not limit, the technical ideas disclosed in this document, and such embodiments do not limit the scope of the technical ideas disclosed in this document. The scope of protection of the technical ideas disclosed in this document should be interpreted according to the claims below, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this document. [Explanation of symbols]

[0093] 1 battery pack 2 Upper controller 10 battery cells 12 sensors 14 Switching section 20 Battery Management System (BMS) 100 Battery management device 110 Information Acquisition Department 120 Controller

Claims

1. an information acquisition unit that acquires open circuit voltages of a plurality of battery cells; calculating a first voltage of each of the plurality of battery cells relating to a change in open circuit voltage of the plurality of battery cells during a predetermined time period; calculating a second voltage that is an average of the first voltages of the plurality of battery cells; calculating a deviation based on the first voltage and the second voltage of each of the plurality of battery cells; a controller that diagnoses the plurality of battery cells based on the ratio and the deviation between the first voltage and the second voltage of each of the plurality of battery cells; A battery management device comprising:

2. The controller diagnosing the plurality of battery cells a plurality of times; 2. The battery management device according to claim 1, wherein a battery cell that has been diagnosed a set number of times or more is finally diagnosed as a defective battery cell.

3. The controller The battery management device according to claim 2 , wherein the plurality of battery cells are discharged a plurality of times, and then the plurality of battery cells are diagnosed for each discharge.

4. The controller The battery management device according to claim 1 , wherein a battery cell of the plurality of battery cells, in which a ratio of the first voltage to the second voltage does not fall within a preset range, is diagnosed as a defective battery cell.

5. The battery management device according to claim 1 , wherein the first voltage is an open circuit voltage value that is recovered after use of the battery cell.

6. The information acquisition unit The battery management device according to claim 1 , wherein the open circuit voltages of the plurality of battery cells are acquired after a preset time has elapsed since the charging or discharging of the plurality of battery cells.

7. The controller 2. The battery management device according to claim 1, wherein among the plurality of battery cells, a battery cell in which the ratio of the first voltage to the second voltage is not within a predetermined range and the deviation between the first voltage and the second voltage is equal to or greater than a predetermined value is diagnosed as a defective battery cell.

8. The controller 8. The battery management device according to claim 7, wherein a battery cell is finally diagnosed as defective when the ratio is not within a predetermined range and the second voltage deviation is equal to or greater than a set value for a set number of consecutive times.

9. The controller The battery management device according to claim 1 , wherein when a change in the open circuit voltage of one of the plurality of battery cells is equal to or greater than a threshold, the battery management device determines that the change is noise without performing a diagnosis.

10. The controller defining a ranking of each of the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells; The battery management device according to claim 1 , wherein the plurality of battery cells are diagnosed based on the ranking of each of the plurality of battery cells.

11. The controller determining a first battery cell having the highest ratio of the first voltage to the second voltage, a second battery cell having the second highest ratio, and a third battery cell having the lowest ratio of the first voltage to the second voltage among the plurality of battery cells; calculating a first difference between the ratio of the first battery cell and the ratio of the second battery cell; calculating a second difference between the ratio of the second battery cell and the ratio of the third battery cell; The battery management device according to claim 10 , wherein the state of the first battery cell is diagnosed based on the ratio of the first battery cell, the first difference, and the second difference.

12. The controller the ratio of the first battery cell is equal to or greater than a first threshold; The battery management device according to claim 11 , wherein a battery cell for which the ratio of the first difference to the second difference is equal to or greater than a second threshold value and the deviation is equal to or greater than a set value is diagnosed as a defective battery cell.

13. obtaining open circuit voltages of a plurality of battery cells; calculating a first voltage of each of the plurality of battery cells relating to a change in open circuit voltage of the plurality of battery cells over a predetermined time period; calculating a second voltage that is an average of the first voltages of the plurality of battery cells; calculating a deviation based on the first voltage and the second voltage of each of the plurality of battery cells; diagnosing the plurality of battery cells based on the ratio and the deviation between the first voltage and the second voltage of each of the plurality of battery cells; A method of operating a battery management device, comprising:

14. the step of diagnosing the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells, diagnosing the plurality of battery cells a plurality of times; The method for operating a battery management device according to claim 13, further comprising the step of finally diagnosing a battery cell that has been diagnosed a set number of times or more as a defective battery cell.

15. The step of diagnosing the plurality of battery cells a plurality of times includes: The method for operating a battery management device according to claim 14 , further comprising the step of: discharging the plurality of battery cells a plurality of times, and then diagnosing the plurality of battery cells for each discharge.

16. the step of diagnosing the plurality of battery cells based on a ratio between the first voltage and the second voltage of each of the plurality of battery cells, The method of claim 13 , further comprising diagnosing, as a defective battery cell, a battery cell among the plurality of battery cells in which a ratio of a first voltage to the second voltage does not fall within a preset range.

17. The step of acquiring open circuit voltages of the plurality of battery cells includes: The method for operating a battery management device according to claim 13 , further comprising obtaining open circuit voltages of the plurality of battery cells after a preset time has elapsed since the charging or discharging of the plurality of battery cells.

18. defining a ranking of each of the plurality of battery cells based on a ratio between a first voltage and the second voltage of each of the plurality of battery cells; The method of claim 13 , further comprising: diagnosing the plurality of battery cells based on the ranking of each of the plurality of battery cells.

19. The step of diagnosing the plurality of battery cells based on the rankings of the plurality of battery cells includes: determining a first battery cell having the highest ratio of the first voltage to the second voltage, a second battery cell having the second highest ratio, and a third battery cell having the lowest ratio of the first voltage to the second voltage among the plurality of battery cells; calculating a first difference between a ratio of the first battery cell and a ratio of the second battery cell; calculating a second difference between the ratio of the second battery cell and the ratio of the third battery cell; and diagnosing a state of the first battery cell based on the ratio of the first battery cell, the first difference, and the second difference.

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