Battery diagnostic device and its operating method

Abstract

A battery diagnostic device according to one embodiment disclosed herein may include: an acquisition unit that acquires voltage data of a plurality of battery cells included in a battery module during a rest period; a deviation calculation unit that calculates the voltage deviation between adjacent periods at a specified time interval from a specified point in time, for cell groups connected in parallel among the plurality of battery cells, based on the voltage data; a cumulative calculation unit that calculates a cumulative deviation by cumulatively summing the voltage deviations for each cell group if the maximum voltage deviation among the plurality of voltage deviations in the target period of the plurality of cell groups is equal to or greater than a first threshold; and a diagnostic unit that diagnoses a battery cell included in a cell group that satisfies a specified condition among the plurality of cell groups as an abnormal battery cell, based on the voltage deviation and the cumulative deviation.

Description

Technical Field

[0001] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2023-0101177 filed on August 2, 2023, and all the contents disclosed in the literature of the Korean patent application are incorporated herein as part of this specification. The embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

Background Art

[0002] In recent years, research and development on secondary batteries have been actively conducted. Here, a secondary battery is a battery capable of charging and discharging, and includes both conventional Ni / Cd batteries, Ni / MH batteries, etc. and recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density compared to conventional Ni / Cd batteries, Ni / MH batteries, etc. In addition, since lithium-ion batteries can be manufactured in a small and lightweight manner, they are used as a power source for mobile devices, and in recent years, their usage range has been extended to the power source of electric vehicles, and they have attracted attention as a next-generation energy storage medium.

[0003] In addition, a secondary battery can generally be used as a battery pack including a battery module in which a plurality of battery cells are connected in series and / or in parallel. And a secondary battery can be used as a battery rack including a plurality of battery modules and a rack frame for accommodating such battery modules.

[0004] Such battery cells, battery modules, battery packs, or battery racks can be utilized in various devices. As an example, a battery can be utilized not only in mobile devices such as mobile phones, laptop computers, smartphones, and smart pads, but also in fields such as electrically driven vehicles (EV, HEV, PHEV) and large-capacity power storage devices (ESS).

Summary of the Invention

Problems to be Solved by the Invention

[0005] Batteries can catch fire during use, and one of the most likely causes is internal short circuits resulting from lithium deposition on the negative electrode surface. In a normal battery, lithium ions released from the positive electrode enter the negative electrode during charging. However, in a defective battery, some lithium ions are deposited from the negative electrode surface in the form of lithium metal. 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. If such an internal short circuit in a battery becomes severe, it can lead to a fire due to thermal runaway. Therefore, measures are needed to detect in advance whether or not there is a battery abnormality and reduce the possibility of damage to the device, including the battery.

[0006] The embodiments disclosed in this document provide a battery diagnostic device and a method for operating it that can diagnose the presence or absence of lithium deposition in a battery and / or the presence or absence of a break in the negative electrode tab using the voltage deviation of the battery and the cumulative deviation obtained by accumulating and summing these deviations.

[0007] The technical problems of the embodiments disclosed in this document are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A battery diagnostic device according to one embodiment disclosed herein may include: an acquisition unit that acquires voltage data of a plurality of battery cells included in a battery module during a rest period; a deviation calculation unit that calculates the voltage deviation between adjacent periods at a specified time interval from a specified point in time, for cell groups connected in parallel among the plurality of battery cells, based on the voltage data; a cumulative calculation unit that calculates a cumulative deviation by cumulatively summing the voltage deviations for each cell group if the maximum voltage deviation among the plurality of voltage deviations in the target period of the plurality of cell groups is equal to or greater than a first threshold; and a diagnostic unit that diagnoses a battery cell included in a cell group that satisfies a specified condition among the plurality of cell groups as an abnormal battery cell, based on the voltage deviation and the cumulative deviation.

[0009] In a battery diagnostic device according to one embodiment disclosed in this document, the cumulative calculation unit can calculate the cumulative deviation by cumulatively summing the voltage deviations only for intervals in which the average value of the multiple cumulative deviations of the multiple cell groups is less than a second threshold.

[0010] A battery diagnostic device according to one embodiment disclosed herein further includes a ratio calculation unit that calculates a first ratio for each cell group by dividing the cumulative deviation by the larger of the average value of the plurality of cumulative deviations and the second threshold value, and the diagnostic unit can diagnose a battery cell included in a cell group that satisfies the specified conditions as an abnormal battery cell based on the first ratio.

[0011] A battery diagnostic device according to one embodiment disclosed herein further includes a correction unit that corrects the first ratio to a second ratio using the OCV (Open Circuit Voltage) deviation due to the change in SOC (State of Charge) on a cell group basis, and the diagnostic unit can diagnose a battery cell included in a cell group that satisfies the specified conditions as an abnormal battery cell based on the second ratio.

[0012] In a battery diagnostic device according to one embodiment disclosed in this document, the correction unit can calculate an OCV deviation ratio for each cell group by dividing the OCV deviation by the average value of the multiple OCV deviations of the multiple cell groups, and can calculate a second ratio for each cell group by dividing the first ratio by the larger of the OCV deviation ratio and a specified value.

[0013] In a battery diagnostic device according to one embodiment disclosed herein, the specified conditions may include a first condition in which the difference between the voltage deviation in the diagnostic cycle and the average value of the multiple voltage deviations of the multiple cell groups in the diagnostic cycle is less than or equal to a third threshold.

[0014] In a battery diagnostic device according to one embodiment disclosed herein, the specified condition may include a second condition in which the second ratio in the diagnostic cycle is the maximum value among a plurality of second ratios in the diagnostic cycle of the plurality of cell groups.

[0015] In a battery diagnostic device according to one embodiment disclosed herein, the specified conditions may include a third condition in which the second ratio in the diagnostic cycle is equal to or greater than a fourth threshold.

[0016] In a battery diagnostic device according to one embodiment disclosed herein, the specified conditions may include a fourth condition in which the second ratio in the diagnostic cycle is the maximum value among a plurality of second ratios in the diagnostic cycle of the plurality of cell groups, and the difference between the second ratio in the diagnostic cycle and the second largest value among the plurality of second ratios is greater than or equal to a fifth threshold.

[0017] A battery diagnostic method according to one embodiment disclosed herein may include: an operation to acquire voltage data of a plurality of battery cells included in a battery module during the idle period; an operation to calculate the voltage deviation between adjacent periods at a specified time interval from a specified point in time, for cell groups connected in parallel among the plurality of battery cells, based on the voltage data; an operation to calculate a cumulative deviation by cumulatively summing the voltage deviations for each cell group if the maximum voltage deviation among the plurality of voltage deviations in the target period of the plurality of cell groups is equal to or greater than a first threshold; and an operation to diagnose a battery cell that is included in a cell group among the plurality of cell groups that satisfies a specified condition as an abnormal battery cell, based on the voltage deviation and the cumulative deviation.

[0018] In a battery diagnostic method according to one embodiment disclosed in this document, the operation for calculating the cumulative deviation may include an operation to calculate the cumulative deviation by cumulatively summing the voltage deviations only for intervals in which the average value of the multiple cumulative deviations of the multiple cell groups is less than a second threshold.

[0019] A battery diagnostic method according to one embodiment disclosed herein further includes an operation to calculate a first ratio for each cell group by dividing the cumulative deviation by the larger of the average value of the plurality of cumulative deviations and the second threshold, and the diagnostic operation may include an operation to diagnose battery cells included in a cell group that satisfy the specified conditions as abnormal battery cells based on the first ratio.

[0020] A battery diagnostic method according to one embodiment disclosed herein further includes an operation to correct the first ratio to a second ratio using the OCV (Open Circuit Voltage) deviation due to the change in SOC (State of Charge) on a cell group basis, and the diagnostic operation may include an operation to diagnose battery cells included in a cell group that satisfy the specified conditions as abnormal battery cells based on the second ratio.

[0021] The battery diagnosis method according to one embodiment disclosed in this document further includes an operation of calculating, for each cell group, an OCV deviation ratio obtained by dividing the OCV deviation by the average value of the OCV deviations of the plurality of cell groups. The operation of correcting the first ratio to the second ratio can include an operation of calculating, for each cell group, the second ratio obtained by dividing the first ratio by the larger value between the OCV deviation ratio and a specified value.

[0022] In the battery diagnosis method according to one embodiment disclosed in this document, the specified conditions can include at least one of the following: a first condition that a difference value between the voltage deviation in a diagnosis cycle and the average value of the plurality of voltage deviations in the diagnosis cycle of the plurality of cell groups is not more than a third threshold value; a second condition that the second ratio in a diagnosis cycle is the maximum value among the plurality of second ratios of the plurality of cell groups in the diagnosis cycle; a third condition that the second ratio in a diagnosis cycle is not less than a fourth threshold value; or a fourth condition that the second ratio in a diagnosis cycle is the maximum value among the plurality of second ratios of the plurality of cell groups in the diagnosis cycle, and a difference value between the second ratio in the diagnosis cycle and the second largest value among the plurality of second ratios is not less than a fifth threshold value.

Advantages of the Invention

[0023] According to the embodiment disclosed in this document, by diagnosing a battery in which a disconnection of a negative electrode tab has occurred and / or a battery in which a disconnection of a negative electrode tab and lithium precipitation have occurred, it is possible to track and manage a battery that may progress to an internal short circuit thereafter. In addition, according to this document, various effects that can be grasped directly or indirectly can be provided.

Brief Description of the Drawings

[0024] [Figure 1] It is a block diagram of a battery diagnosis device according to one embodiment. [Figure 2] It is a block diagram of a calculation unit in a battery diagnosis device according to one embodiment. [Figure 3]It is a diagram showing the voltage of a rest period acquired by a battery diagnostic device according to an embodiment. [Figure 4] It is a diagram showing the voltage deviation calculated by a battery diagnostic device according to an embodiment. [Figure 5] It is a diagram showing the cumulative deviation calculated by a battery diagnostic device according to an embodiment. [Figure 6] It is a diagram showing the second ratio calculated by a battery diagnostic device according to an embodiment. [Figure 7] It is an operation flowchart of a battery diagnostic device according to an embodiment. [Figure 8] It is an operation flowchart of a battery diagnostic device according to an embodiment. [Figure 9] It is an operation flowchart of a battery diagnostic device according to an embodiment.

Mode for Carrying Out the Invention

[0025] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include various modifications, equivalents, and / or alternatives of the embodiments of the present invention.

[0026] Various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and it should be understood to include various modifications, equivalents, or alternatives of the embodiments. For components that are similar or related in connection with the description of the drawings, similar reference numerals may be used. The singular form of the noun corresponding to an item may include one or more of the said items unless clearly indicated otherwise in the relevant context.

[0027] In this document, each phrase such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C” may include any one of the items listed together with the applicable phrase, or any possible combination thereof. Terms such as “first,” “second,” “first,” “second,” “A,” “B,” “(a),” or “(b)” may be used simply to distinguish one component from other components and, unless otherwise stated, do not limit the component in any other respect (e.g., importance or order).

[0028] Wherever a component (e.g., the first) is referred to as being "coupled," "joined," or "connected" to another component (e.g., the second) with or without such terms, it means that the first component may be connected to the other component directly (e.g., by wire), wirelessly, or via the third component.

[0029] According to various embodiments, each of the aforementioned components (e.g., a module or a program) may include one or more individuals, and some of the individuals may be separated and arranged in other components. According to various embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Alternatively or additionally, multiple components (e.g., a module or a program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the components of the multiple components before the integration. According to various embodiments, operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0030] The configuration of the battery diagnostic device will be described below with reference to Figures 1 and 2. Figure 1 is a block diagram of a battery diagnostic device according to one embodiment. Figure 2 is a block diagram of a calculation unit within the battery diagnostic device according to one embodiment.

[0031] The battery diagnostic device 101, described later, may be implemented in a Battery Management System (BMS) within an electronic device including the battery module 102, or it may be implemented in various external devices such as a server, cloud, charger, or charger / discharger.

[0032] Referring to Figure 1, the battery diagnostic device 101 may include a communication circuit 110, a sensor 120, a memory 130, and a processor 140. According to the embodiment, the battery diagnostic device 101 shown in Figure 1 may further include at least one component other than those shown in Figure 1 (e.g., a display, an input device, or an output device), and at least one component of those shown in Figure 1 (e.g., the sensor 120) may be omitted.

[0033] According to one embodiment, the battery module 102 includes a plurality of cell groups 150, 160, and 170, and each cell group 150, 160, or 170 may include a plurality of battery cells connected in parallel with each other. For example, the first cell group 150 may include a plurality of battery cells 151, 153, and 155 connected in parallel with each other, the second cell group 160 may include a plurality of battery cells 161, 163, and 165 connected in parallel with each other, and the third cell group 170 may include a plurality of battery cells 171, 173, and 175 connected in parallel with each other.

[0034] According to one embodiment, the battery diagnostic device 101 can acquire data related to the status (e.g., voltage, current, or temperature, etc.) of multiple cell groups 150, 160, 170 contained in the battery module 102 using a communication circuit 110 and / or a sensor 120.

[0035] According to one embodiment, the communication circuit 110 establishes a wired communication channel and / or wireless communication channel between the battery diagnostic device 101 and an electronic device including a battery module 102 and / or a user terminal 103, and can send and receive data with the electronic device including the battery module 102 and / or the user terminal 103 via the established communication channel. Here, the electronic device including the battery module 102 may be a mobile device (e.g., a mobile phone, laptop computer, smartphone, smartpad), an electric vehicle (e.g., an EV (electric vehicle), a HEV (hybrid EV), a PHEV (plug-in HEV), a FCEV (fuel cell EV)), an energy storage system (ESS), or a battery swapping system (BSS).

[0036] For example, if the battery diagnostic device 101 is implemented on an external device such as a server or cloud, the battery diagnostic device 101 can use the communication circuit 110 to acquire data related to the status of multiple cell groups 150, 160, and 170 from an electronic device including a battery module 102. In this case, the battery diagnostic device 101 does not need to include the sensor 120.

[0037] According to one embodiment, the user terminal 103 may be a mobile device (e.g., a mobile phone, laptop computer, smartphone, smartpad) or a PC (personal computer). According to one embodiment, the battery diagnostic device 101 can use the communication circuit 110 to transmit data related to the diagnostic results for cell groups 150, 160, or 170 to the user terminal 103.

[0038] According to one embodiment, the sensor 120 can measure the state values ​​of multiple cell groups 150, 160, and 170. For example, if the battery diagnostic device 101 is implemented in a BMS within an electronic device including a battery module 102 (e.g., a module BMS of the battery module 102), the battery diagnostic device 101 can directly measure the state values ​​of multiple cell groups 150, 160, and 170 using the sensor 120.

[0039] According to one embodiment, the memory 130 may include volatile memory and / or non-volatile memory. According to one embodiment, the memory 130 can store data used by at least one component of the battery diagnostic device 101 (e.g., the processor 140). For example, the data may include software (or associated instructions), input data, or output data. In one embodiment, the instructions can cause the battery diagnostic device 101 to perform the operation defined by the instructions when executed by the processor 140.

[0040] According to one embodiment, the memory 130 may include one or more software (for example, an acquisition unit 131, a calculation unit 132, a correction unit 133, and a diagnostic unit 134).

[0041] According to one embodiment, the processor 140 may include a central processing unit, an application processor, a graphics processing unit, an NPU (neural processing unit), an image signal processor, a sensor hub processor, or a communication processor.

[0042] According to one embodiment, the processor 140 can execute software (e.g., acquisition unit 131, calculation unit 132, correction unit 133, and diagnostic unit 134), control at least one other component (e.g., hardware or software component) of the battery diagnostic device 101 connected to the processor 140, and perform various data processing or calculations.

[0043] The following describes how the battery diagnostic device 101 diagnoses abnormalities in cell groups 150, 160, and 170 via the acquisition unit 131, calculation unit 132, correction unit 133, and / or diagnostic unit 134, with reference to Figures 3 to 6.

[0044] Figure 3 shows the voltage during the idle period acquired by the battery diagnostic device according to one embodiment. Figure 4 shows the voltage deviation calculated by the battery diagnostic device according to one embodiment. Figure 5 shows the cumulative deviation calculated by the battery diagnostic device according to one embodiment. Figure 6 shows the second ratio calculated by the battery diagnostic device according to one embodiment.

[0045] According to one embodiment, the acquisition unit 131 can acquire voltage data of the idle periods of multiple cell groups 150, 160, and 170 using the communication circuit 110 and / or the sensor 120. Here, the idle period may mean the idle period after charging or the idle period after discharging of the multiple cell groups 150, 160, and 170. For example, the acquisition unit 131 can acquire voltage data of the idle periods of the first cell group 150, the second cell group 160, and the third cell group 170, as shown in graph 300 of Figure 3.

[0046] According to one embodiment, the deviation calculation unit 210 included in the calculation unit 132 can calculate the voltage deviation in units of cell groups 150, 160, or 170 at a specified time interval from a specified point in time, based on the voltage data acquired by the acquisition unit 131. Here, the voltage deviation may mean the voltage deviation between adjacent periods of cell groups 150, 160, or 170. Adjacent periods may mean, for example, the period for which the voltage deviation is to be calculated and the period immediately preceding the target period. That is, the voltage deviation may mean the difference between the voltage of cell groups 150, 160, or 170 in the target period and the voltage of cell groups 150, 160, or 170 in the period immediately preceding the specified time before the target period.

[0047] For example, the deviation calculation unit 210 can calculate the voltage deviation between adjacent periods of the first cell group 150, the second cell group 160, and the third cell group 170, as shown in graph 400 of Figure 4, at 200-second intervals starting 600 seconds after entering the pause period, based on the voltage data of the pause period as shown in graph 300 of Figure 3.

[0048] According to one embodiment, the cumulative calculation unit 220 included in the calculation unit 132 can calculate the cumulative deviation by cumulatively summing the voltage deviations calculated by the deviation calculation unit 210 in units of 150, 160, or 170 cell groups.

[0049] According to one embodiment, the cumulative calculation unit 220 can calculate the cumulative deviations corresponding to the first cell group 150, the second cell group 160, and the third cell group 170, respectively, based on voltage deviation data such as graph 400 in Figure 4, as shown in graph 500 in Figure 5.

[0050] According to one embodiment, the cumulative calculation unit 220 can calculate the cumulative deviation by cumulatively summing the voltage deviations in units of cell groups 150, 160, or 170, only for periods in which the maximum voltage deviation among the multiple voltage deviations of multiple cell groups 150, 160, and 170 calculated by the deviation calculation unit 210 is equal to or greater than a first threshold (for example, 0.5 mV).

[0051] For example, the cumulative calculation unit 220 can calculate the cumulative deviation by cumulatively summing the voltage deviations in the target period for each of the cell groups 150, 160, or 170, only if the maximum voltage deviation among the multiple voltage deviations in the target period for each of the cell groups 150, 160, or 170 is equal to or greater than a first threshold. In other words, in this case, the cumulative deviation in the target period may be a value updated by adding the voltage deviation in the target period to the cumulative deviation in the immediately preceding period.

[0052] As another example, the cumulative calculation unit 220 may exclude a voltage deviation in a target period from the cumulative sum if the maximum voltage deviation among the multiple voltage deviations in the target period of a plurality of cell groups 150, 160, and 170 is less than a first threshold. In other words, in this case, the cumulative deviation in the target period may be the same value as the cumulative deviation in the immediately preceding period.

[0053] According to one embodiment, the first threshold value may be a value related to the noise level generated during voltage measurement. That is, the cumulative calculation unit 220 can improve diagnostic accuracy by not accumulating and summing the voltage deviation in the cumulative deviation when the voltage measurement noise level is equal to or greater than the threshold level.

[0054] According to one embodiment, the cumulative calculation unit 220 can calculate the cumulative deviation by cumulatively summing the voltage deviations in units of cell groups 150, 160, or 170, but only for intervals where the average value of multiple cumulative deviations of multiple cell groups 150, 160, and 170 is less than a second threshold (e.g., 1 mV). Here, the second threshold may be a value set to prevent the cumulative deviation from continuously increasing without limit.

[0055] For example, if the cumulative calculation unit 220 finds that the average value of the multiple cumulative deviations calculated up to the immediately preceding period is equal to or greater than the second threshold for a given period, it can calculate the cumulative deviation calculated up to the immediately preceding period as the final cumulative deviation corresponding to that period without further summing of voltage deviations. Alternatively, the cumulative calculation unit 220 can calculate the final cumulative deviation corresponding to the next period by accumulating and summing the voltage deviations from the given period up to the immediately preceding period in which the average value is equal to or greater than the second threshold for another period.

[0056] According to one embodiment, the ratio calculation unit 230 included in the calculation unit 132 can calculate a first ratio in units of cell groups 150, 160, or 170 using the cumulative deviation calculated by the cumulative calculation unit 220. Here, the first ratio may be the value obtained by dividing the cumulative deviation of cell groups 150, 160, or 170 by the larger of the average value of the multiple cumulative deviations of the multiple cell groups 150, 160, and 170 and the second threshold.

[0057] According to one embodiment, the correction unit 133 can correct the first ratio calculated by the ratio calculation unit 230 to a second ratio using the OCV (Open Circuit Voltage) deviation due to the change in SOC (State of Charge). Here, the OCV deviation may mean the difference in OCV of cell groups 150, 160, or 170 due to a change in SOC (for example, a 1% change in SOC) within the SOC range specified in units of cell groups 150, 160, or 170.

[0058] Voltage fluctuations during battery idle periods can be affected by the slope of the OCV voltage curve; therefore, voltage deviations in idle periods within cell groups contained in the same battery module can differ from one another depending on the OCV deviation. This allows for improved diagnostic accuracy by correcting the first ratio for cell group-specific diagnosis using the OCV deviation of each cell group.

[0059] According to one embodiment, the correction unit 133 can calculate an OCV deviation ratio by dividing the OCV deviation by the average value of multiple OCV deviations in multiple cell groups 150, 160, or 170, in units of cell groups 150, 160, or 170. The correction unit 133 can also calculate a second ratio by dividing the first ratio calculated by the ratio calculation unit 230 by the larger of the OCV deviation ratio and a specified value (for example, 1), in units of cell groups 150, 160, or 170.

[0060] For example, the correction unit 133 can calculate a second ratio of the first cell group 150, the second cell group 160, and the third cell group 170, as shown in graph 600 of Figure 6.

[0061] According to one embodiment, the diagnostic unit 134 can diagnose abnormalities in cell groups 150, 160, or 170 based on at least one of the following: the voltage deviation calculated by the deviation calculation unit 210, the cumulative deviation calculated by the cumulative calculation unit 220, the first ratio calculated by the ratio calculation unit 230, or the second ratio corrected by the correction unit 133.

[0062] According to one embodiment, the diagnostic unit 134 can diagnose a battery cell that is included in one of the cell groups 150, 160, or 170 that satisfies a specified condition as an abnormal battery cell.

[0063] According to one embodiment, the specified conditions may include a first condition in which the difference between the voltage deviation calculated by the deviation calculation unit 210 during the diagnostic cycle and the average value of multiple voltage deviations calculated by the deviation calculation unit 210 during the diagnostic cycle for multiple cell groups 150, 160, and 170 is less than or equal to a third threshold (e.g., 10 mV).

[0064] According to one embodiment, the specified condition may include a second condition in which the second ratio corrected by the correction unit 133 in the diagnostic cycle is the maximum value among a plurality of second ratios corrected by the correction unit 133 in the diagnostic cycle of a plurality of cell groups 150, 160, and 170.

[0065] According to one embodiment, the specified conditions may include a third condition in which the second ratio corrected by the correction unit 133 in the diagnostic cycle is greater than or equal to a fourth threshold (e.g., 1.5).

[0066] According to one embodiment, the specified conditions may include a fourth condition in which the second ratio corrected by the correction unit 133 in the diagnostic cycle is the maximum value among a plurality of second ratios corrected by the correction unit 133 in the diagnostic cycle for a plurality of cell groups 150, 160, and 170, and the difference between the second ratio in the diagnostic cycle and the second largest value among the plurality of second ratios is greater than or equal to a fifth threshold (0.5).

[0067] According to one embodiment, the diagnostic unit 134 can diagnose a battery cell included in a cell group 150, 160, or 170 that satisfies all of the conditions included in the specified conditions as an abnormal battery cell. According to another embodiment, the diagnostic unit 134 may diagnose a battery cell included in a cell group 150, 160, or 170 from among a plurality of cell groups 150, 160, and 170 that satisfies a specified number of conditions from at least one of the conditions included in the specified conditions as an abnormal battery cell.

[0068] Figure 7 is an operation flowchart of a battery diagnostic device according to one embodiment. Figure 7 may also be an explanation of the operation of the battery diagnostic device 101 in Figure 1, and will be explained using the configuration of Figure 1.

[0069] The embodiment shown in Figure 7 is only one embodiment, and the order of steps in various embodiments of the present invention may differ from that shown in Figure 7. Some of the steps shown in Figure 7 may be omitted, the order of the steps may be changed, or steps may be merged.

[0070] Referring to Figure 7, in operation 705, the battery diagnostic device 101 can acquire voltage data for the idle periods of multiple cell groups 150, 160, and 170. Here, the idle period may refer to the idle period after charging or the idle period after discharging of the multiple cell groups 150, 160, and 170.

[0071] In operation 710, the battery diagnostic device 101 can calculate the voltage deviation in units of cell groups 150, 160, or 170 at a specified time interval from a specified point in time, based on the voltage data acquired in operation 705. Here, the voltage deviation may mean the voltage deviation between adjacent periods of cell groups 150, 160, or 170. Adjacent periods may mean, for example, the period for which the voltage deviation is to be calculated and the period immediately preceding the target period. That is, the voltage deviation may mean the difference between the voltage of cell group 150, 160, or 170 in the target period and the voltage of cell group 150, 160, or 170 in the period immediately preceding the specified time before the target period.

[0072] In operation 715, the battery diagnostic device 101 can identify whether the maximum voltage deviation among the multiple voltage deviations of the multiple cell groups 150, 160, and 170 calculated in operation 710 is greater than or equal to a first threshold (e.g., 0.5 mV).

[0073] If operation 715 identifies that the maximum voltage deviation is less than the first threshold ("NO"), the battery diagnostic device 101 can re-execute operation 710 in the next cycle after the specified time has elapsed since the target cycle. In this case, the battery diagnostic device 101 can calculate the voltage deviation between the next cycle and the target cycle in the next cycle.

[0074] If operation 715 identifies that the maximum voltage deviation is greater than or equal to the first threshold ("YES"), in operation 720, the battery diagnostic device 101 can calculate the cumulative deviation by cumulatively summing the voltage deviations calculated in operation 710 in units of 150, 160, or 170 cell groups. For example, the battery diagnostic device 101 can calculate the cumulative deviation for the target period by adding the voltage deviation calculated in the target period to the cumulative deviation calculated in the immediately preceding period.

[0075] In operation 725, the battery diagnostic device 101 can determine whether the average value of multiple cumulative deviations of multiple cell groups 150, 160, and 170 calculated in operation 720 is equal to or greater than a second threshold (e.g., 1 mV).

[0076] If operation 725 identifies that the average value is less than the second threshold ("NO"), the battery diagnostic device 101 can re-execute operation 710 in the next cycle after the specified time has elapsed since the target cycle. In this case, the battery diagnostic device 101 can calculate the voltage deviation between the next cycle and the target cycle in the next cycle.

[0077] If in operation 725 it is identified that the average value is equal to or greater than the second threshold ("YES"), then in operation 730 the battery diagnostic device 101 can diagnose an abnormality in cell group 150, 160, or 170 based on the voltage deviation calculated in operation 710 and the cumulative deviation calculated in operation 720. According to one embodiment, the battery diagnostic device 101 may further diagnose an abnormality in cell group 150, 160, or 170 based on a first ratio and / or a second ratio, which will be described later with reference to Figure 8.

[0078] According to one embodiment, the battery diagnostic device 101 can diagnose a battery cell that is included in cell group 150, 160, or 170 that satisfies specified conditions as an abnormal battery cell. Here, the specified conditions may include the first to fourth conditions described above in Figure 1.

[0079] According to one embodiment, the battery diagnostic device 101 can diagnose battery cells included in cell groups 150, 160, or 170 that satisfy all of the specified conditions as abnormal battery cells. This embodiment will be described in detail with reference to Figure 9, which will be described later.

[0080] According to another embodiment, the battery diagnostic device 101 may diagnose battery cells belonging to a plurality of cell groups 150, 160, or 170 that satisfy a specified number of conditions among at least one of the specified conditions as abnormal battery cells.

[0081] Figure 8 is an operation flowchart of a battery diagnostic device according to one embodiment. Figure 8 may also be an explanation of the operation of the battery diagnostic device 101 in Figure 1, and will be explained using the configuration of Figure 1.

[0082] The embodiment shown in Figure 8 is only one embodiment, and the order of steps in various embodiments of the present invention may differ from that shown in Figure 8. Some of the steps shown in Figure 8 may be omitted, the order of the steps may be changed, or steps may be merged.

[0083] Referring to Figure 8, in operation 805, the battery diagnostic device 101 can calculate the first ratio in units of cell groups 150, 160, or 170. According to one embodiment, the battery diagnostic device 101 can calculate the first ratio using the cumulative deviation calculated in operation 720 of Figure 7. Here, the first ratio may be the value obtained by dividing the cumulative deviation of cell groups 150, 160, or 170 by the larger of the average value of the multiple cumulative deviations of the multiple cell groups 150, 160, and 170 and the second threshold.

[0084] In operation 810, the battery diagnostic device 101 can correct the first ratio calculated in operation 805 to the second ratio using the OCV deviation due to the change in SOC. Here, the OCV deviation may mean the difference in OCV of cell groups 150, 160, or 170 due to a change in SOC (e.g., a 1% change in SOC) within the SOC range specified in units of cell groups 150, 160, or 170.

[0085] Voltage fluctuations during battery idle periods can be affected by the slope of the OCV voltage curve; therefore, voltage deviations in idle periods within cell groups contained in the same battery module can differ from one another depending on the OCV deviation. This allows for improved diagnostic accuracy by correcting the first ratio for cell group-specific diagnosis using the OCV deviation of each cell group.

[0086] According to one embodiment, the battery diagnostic device 101 can calculate an OCV deviation ratio by dividing the OCV deviation by the average value of multiple OCV deviations of multiple cell groups 150, 160, or 170, in units of cell groups 150, 160, or 170. The battery diagnostic device 101 can also calculate a second ratio by dividing the first ratio calculated in operation 805 by the larger of the OCV deviation ratio and a specified value (for example, 1), in units of cell groups 150, 160, or 170.

[0087] In operation 815, the battery diagnostic device 101 can diagnose an abnormality in cell group 150, 160, or 170 based on the second ratio corrected in operation 810.

[0088] According to one embodiment, the battery diagnostic device 101 can diagnose a battery cell that is included in cell group 150, 160, or 170 that satisfies specified conditions as an abnormal battery cell. Here, the specified conditions may include the first to fourth conditions described above in Figure 1.

[0089] According to one embodiment, the battery diagnostic device 101 can diagnose battery cells included in cell groups 150, 160, or 170 that satisfy all of the specified conditions as abnormal battery cells. This embodiment will be described in detail with reference to Figure 9, which will be described later.

[0090] According to another embodiment, the battery diagnostic device 101 may diagnose battery cells belonging to a plurality of cell groups 150, 160, or 170 that satisfy a specified number of conditions among at least one of the specified conditions as abnormal battery cells.

[0091] Figure 9 is an operation flowchart of a battery diagnostic device according to one embodiment. Figure 9 may also be an explanation of the operation of the battery diagnostic device 101 in Figure 1, and will be explained using the configuration of Figure 1.

[0092] The embodiment shown in Figure 9 is only one embodiment, and the order of steps in various embodiments of the present invention may differ from that shown in Figure 9. Some of the steps shown in Figure 9 may be omitted, the order of the steps may be changed, or steps may be merged.

[0093] Referring to Figure 9, in operation 905, the battery diagnostic device 101 can determine whether the difference between the voltage deviation of the cell group 150, 160, or 170 to be diagnosed during its diagnostic cycle and the average value of multiple voltage deviations during the diagnostic cycles of multiple cell groups 150, 160, and 170 is less than or equal to a third threshold (e.g., 10 mV).

[0094] If operation 905 identifies that the difference value exceeds the third threshold ("NO"), then in operation 910, the battery diagnostic device 101 can diagnose the target cell group 150, 160, or 170 as a normal cell group.

[0095] If the difference value is identified as being less than or equal to the third threshold in operation 905 ("YES"), then in operation 915, the battery diagnostic device 101 can identify whether the second ratio in the diagnostic cycle of the cell group 150, 160, or 170 corresponds to the maximum value among multiple second ratios in the diagnostic cycles of multiple cell groups 150, 160, and 170.

[0096] If, in operation 915, the second ratio of the cell group to be diagnosed 150, 160, or 170 is identified as not being the maximum value ("NO"), then in operation 910, the battery diagnostic device 101 can diagnose the cell group to be diagnosed 150, 160, or 170 as a normal cell group.

[0097] If operation 915 identifies that the second ratio of the cell group 150, 160, or 170 to be diagnosed corresponds to the maximum value ("YES"), then in operation 920, the battery diagnostic device 101 can identify whether the second ratio of the cell group 150, 160, or 170 in the diagnostic cycle is equal to or greater than the fourth threshold (e.g., 1.5).

[0098] If operation 920 identifies that the second ratio of the cell group 150, 160, or 170 to be diagnosed is less than the fourth threshold ("NO"), then in operation 910, the battery diagnostic device 101 can diagnose the cell group 150, 160, or 170 to be diagnosed as a normal cell group.

[0099] If operation 920 identifies that the second ratio of the cell group 150, 160, or 170 to be diagnosed is greater than or equal to the fourth threshold ("YES"), then in operation 925, the battery diagnostic device 101 can identify whether the difference between the second ratio of the cell group 150, 160, or 170 in the diagnostic cycle and the second largest value among the multiple second ratios in the diagnostic cycles of the multiple cell groups 150, 160, and 170 is greater than or equal to the fifth threshold (e.g., 0.5).

[0100] If the difference value is identified as being less than the fifth threshold in operation 925 ("NO"), then in operation 910, the battery diagnostic device 101 can diagnose the target cell group 150, 160, or 170 as a normal cell group.

[0101] If the difference value is identified as being greater than or equal to the fifth threshold in operation 925 ("YES"), then in operation 930, the battery diagnostic device 101 can diagnose the target cell group 150, 160, or 170 as an abnormal cell group. In this case, the battery diagnostic device 101 can diagnose the battery cells included in the target cell group 150, 160, or 170, which has been diagnosed as an abnormal cell group, as abnormal battery cells.

[0102] The terms “contain,” “constitute,” or “have,” as used above, mean “may contain,” and should not be interpreted as meaning that they may contain, unless otherwise specified, other components, rather than excluding them. All terms, including technical or scientific terms, should have the same meaning as that generally understood by a person of ordinary skill in the art to which the embodiments disclosed herein belong, unless otherwise specified. Commonly used terms, such as those defined in dictionaries, should be interpreted to be consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined herein.

Claims

1. An acquisition unit that acquires voltage data during the idle period of multiple battery cells included in a battery module, Based on the voltage data, a deviation calculation unit calculates the voltage deviation between adjacent periods at a specified time interval from a specified point in time, for each cell group among the plurality of battery cells connected in parallel, When the maximum voltage deviation among multiple voltage deviations in the target period of multiple cell groups is greater than or equal to a first threshold, a cumulative calculation unit calculates a cumulative deviation by cumulatively summing the voltage deviations for each cell group, A diagnostic unit that diagnoses battery cells included in a cell group that satisfies a specified condition among the plurality of cell groups based on the voltage deviation and the cumulative deviation as abnormal battery cells, Battery diagnostic device, including

2. The battery diagnostic device according to claim 1, wherein the cumulative calculation unit calculates the cumulative deviation by cumulatively summing the voltage deviations only for intervals in which the average value of the multiple cumulative deviations of the multiple cell groups is less than a second threshold.

3. The system further includes a ratio calculation unit that calculates a first ratio for each cell group by dividing the cumulative deviation by the larger of the mean value of the plurality of cumulative deviations and the second threshold, The battery diagnostic device according to claim 2, wherein the diagnostic unit diagnoses, based on the first ratio, that a battery cell included in a cell group that satisfies the specified conditions is an abnormal battery cell.

4. The system further includes a correction unit that corrects the first ratio to a second ratio using the OCV deviation due to SOC change for each cell group, The battery diagnostic device according to claim 3, wherein the diagnostic unit diagnoses, based on the second ratio, that a battery cell included in a cell group that satisfies the specified conditions is an abnormal battery cell.

5. The correction unit, For each cell group, the OCV deviation ratio is calculated by dividing the OCV deviation by the average value of the multiple OCV deviations of the multiple cell groups. The battery diagnostic device according to claim 4, wherein, for each cell group, the second ratio is calculated by dividing the first ratio by the larger of the OCV deviation ratio and a specified value.

6. The battery diagnostic device according to claim 4, wherein the specified conditions include a first condition in which the difference between the voltage deviation in the diagnostic cycle and the average value of the multiple voltage deviations of the multiple cell groups in the diagnostic cycle is less than or equal to a third threshold.

7. The battery diagnostic device according to claim 4, wherein the specified conditions include a second condition in which the second ratio in the diagnostic cycle is the maximum value among the plurality of second ratios in the diagnostic cycle of the plurality of cell groups.

8. The battery diagnostic device according to claim 4, wherein the specified conditions include a third condition in which the second ratio in the diagnostic cycle is greater than or equal to a fourth threshold.

9. The battery diagnostic device according to claim 4, wherein the specified conditions include a fourth condition in which the second ratio in the diagnostic cycle is the maximum value among the plurality of second ratios in the diagnostic cycle of the plurality of cell groups, and the difference between the second ratio in the diagnostic cycle and the second largest value among the plurality of second ratios is greater than or equal to a fifth threshold.

10. The operation of acquiring voltage data during the idle period of multiple battery cells contained in a battery module, Based on the voltage data, the operation calculates the voltage deviation between adjacent periods at a specified time interval from a specified point in time, for each cell group connected in parallel among the plurality of battery cells. If the maximum voltage deviation among multiple voltage deviations in the target period of multiple cell groups is greater than or equal to a first threshold, the operation of calculating the cumulative deviation by cumulatively summing the voltage deviations for each cell group, Based on the voltage deviation and the cumulative deviation, the operation involves diagnosing battery cells included in the cell group that satisfies the specified conditions among the plurality of cell groups as abnormal battery cells. Battery diagnostic methods, including those mentioned above.

11. The battery diagnostic method according to claim 10, wherein the operation for calculating the cumulative deviation includes an operation to calculate the cumulative deviation by cumulatively summing the voltage deviations only for intervals in which the average value of the multiple cumulative deviations of the multiple cell groups is less than a second threshold.

12. The operation further includes calculating a first ratio for each cell group by dividing the cumulative deviation by the larger of the mean value of the plurality of cumulative deviations and the second threshold, The battery diagnostic method according to claim 11, wherein the diagnostic operation includes an operation to diagnose a battery cell included in a cell group that satisfies the specified conditions as an abnormal battery cell based on the first ratio.

13. The operation further includes correcting the first ratio to the second ratio using the OCV deviation due to SOC change for each cell group, The battery diagnostic method according to claim 12, wherein the diagnostic operation includes an operation to diagnose a battery cell included in a cell group that satisfies the specified conditions as an abnormal battery cell, based on the second ratio.

14. The process further includes calculating an OCV deviation ratio for each cell group by dividing the OCV deviation by the average value of the multiple OCV deviations of the multiple cell groups, The battery diagnostic method according to claim 13, wherein the operation to correct the first ratio to a second ratio includes the operation to calculate the second ratio by dividing the first ratio by the larger of the OCV deviation ratio and a specified value, on a cell group basis.

15. The aforementioned specified conditions are: The first condition is that the difference between the voltage deviation in the diagnostic cycle and the average value of the multiple voltage deviations of the multiple cell groups in the diagnostic cycle is less than or equal to a third threshold, The second condition is that the second ratio in the diagnostic cycle is the maximum value among the multiple second ratios in the diagnostic cycle of the multiple cell groups, The third condition is that the second ratio in the diagnostic cycle is greater than or equal to the fourth threshold, or The battery diagnostic method according to claim 13, comprising at least one of the fourth conditions, wherein the second ratio in the diagnostic cycle is the maximum value among the plurality of second ratios in the diagnostic cycle of the plurality of cell groups, and the difference between the second ratio in the diagnostic cycle and the second largest value among the plurality of second ratios is greater than or equal to a fifth threshold.

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