Battery diagnosis device and operation method thereof

Abstract

A battery diagnosis device according to an embodiment disclosed in the present document may comprise: an acquisition unit for acquiring voltage data in resting periods of a plurality of battery cells included in a battery module; a deviation calculation unit for, on the basis of the voltage data, calculating voltage deviations between adjacent cycles at a designated time interval from a designated time point in units of cell groups connected in parallel to each other among the plurality of battery cells; a cumulative calculation unit for, if a maximum voltage deviation among a plurality of voltage deviations in a target cycle of a plurality of cell groups is greater than or equal to a first threshold value, calculating a cumulative deviation by cumulatively summing the voltage deviations in units of the cell groups; and a diagnosis unit for, on the basis of the voltage deviations and the cumulative deviation, diagnosing, as abnormal battery cells, battery cells included in a cell group satisfying a designated condition among the plurality of cell groups.

Description

Battery diagnostic device and its operating method

[0001] Cross-citation with related applications

[0002] This invention claims the benefit of priority from Korean Patent Application No. 10-2023-0101177, filed on August 2, 2023, and all contents of the document in that Korean Patent Application are incorporated herein by reference.

[0003] Technology field

[0004] The embodiments disclosed in this document relate to a battery diagnostic device and an operating method thereof.

[0005] Recently, research and development on secondary batteries has been actively conducted. Here, secondary batteries are rechargeable and include both conventional Ni / Cd and Ni / MH batteries, as well as recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them suitable for use as power sources for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, attracting attention as a next-generation energy storage medium.

[0006] Additionally, secondary batteries can be utilized as battery packs, which typically include battery modules in which multiple battery cells are connected in series and / or parallel. Furthermore, secondary batteries can be utilized as battery racks, which include multiple battery modules and a rack frame that accommodates these battery modules.

[0007] Battery cells, battery modules, battery packs, or battery racks like these can be utilized in a variety of devices. For example, batteries can be used in mobile devices such as cell phones, laptops, smartphones, and tablets, as well as in electric vehicles (EVs, HEVs, PHEVs) and large-capacity energy storage systems (ESS).

[0008] Batteries can sometimes catch fire during use, and one of the most likely causes of this is an internal short circuit caused by lithium precipitation on the surface of the battery's cathode. In a healthy battery, lithium ions released from the cathode enter the cathode during charging. However, in a defective battery, some lithium ions precipitate as lithium metal on the cathode surface. When this precipitated lithium continues to grow through repeated charging, it comes into contact with the battery's cathode or cathode collector, causing an internal short circuit. If this internal short circuit worsens, it can lead to thermal runaway and a fire.

[0009] Accordingly, a method is required to detect abnormalities in batteries in advance and reduce the possibility of damage to devices containing batteries.

[0010] The embodiments disclosed in this document can provide a battery diagnostic device and an operating method thereof that can diagnose whether lithium deposition and / or a negative tab disconnection of a battery is present by using a battery voltage deviation and an accumulated deviation obtained by accumulating the voltage deviation.

[0011] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the descriptions below.

[0012] According to an embodiment disclosed in the present document, a battery diagnosis device may include an acquisition unit that acquires voltage data in an idle period of a plurality of battery cells included in a battery module, a deviation calculation unit that calculates a voltage deviation between adjacent cycles from a specified time point at a specified time interval in units of cell groups connected in parallel among the plurality of battery cells based on the voltage data, an accumulation calculation unit that calculates an accumulated deviation by cumulatively adding up the voltage deviations in units of the cell groups when a maximum voltage deviation among a plurality of voltage deviations in a target cycle of the plurality of cell groups is equal to or greater than a first threshold value, and a diagnosis unit that diagnoses battery cells included in a cell group that satisfies a specified condition among the plurality of cell groups as abnormal battery cells based on the voltage deviation and the accumulated deviation.

[0013] In a battery diagnostic device according to an embodiment disclosed in this document, the cumulative calculation unit can calculate the cumulative deviation by cumulatively adding up the voltage deviations only for a section in which the average value of the plurality of cumulative deviations of the plurality of cell groups is less than a second threshold value.

[0014] A battery diagnosis device according to an embodiment disclosed in this document further includes a ratio calculation unit that calculates a first ratio by dividing the accumulated deviation by a larger value between the average value of the plurality of accumulated deviations and the second threshold value, for each cell group, and the diagnosis unit can diagnose battery cells included in the cell group that satisfy the specified condition as abnormal battery cells based on the first ratio.

[0015] A battery diagnosis device according to an embodiment disclosed in this document further includes a correction unit that corrects the first ratio to a second ratio by using an OCV (Open Circuit Voltage) deviation according to a change in SOC (State of Charge) for each cell group, and the diagnosis unit can diagnose battery cells included in the cell group that satisfy the specified condition as abnormal battery cells based on the second ratio.

[0016] In a battery diagnosis device according to an embodiment disclosed in this document, the correction unit may calculate, for each cell group, an OCV deviation ratio by dividing the OCV deviation by an average value of a plurality of OCV deviations of the plurality of cell groups, and may calculate, for each cell group, the second ratio by dividing the first ratio by a larger value between the OCV deviation ratio and a specified value.

[0017] In a battery diagnostic device according to an embodiment disclosed in this document, the specified condition may include a first condition in which a difference value between the voltage deviation in the diagnostic period and an average value of the plurality of voltage deviations in the diagnostic period of the plurality of cell groups is less than or equal to a third threshold value.

[0018] In a battery diagnostic device according to an embodiment disclosed in this document, the specified condition may include a second condition in which the second ratio in the diagnostic period is a maximum value among a plurality of second ratios in the diagnostic period of the plurality of cell groups.

[0019] In a battery diagnostic device according to an embodiment disclosed in this document, the specified condition may include a third condition in which the second ratio in the diagnostic cycle is equal to or greater than a fourth threshold value.

[0020] In a battery diagnostic device according to an embodiment disclosed in the present document, the specified condition may include a fourth condition in which the second ratio in the diagnostic period is a maximum value among a plurality of second ratios in the diagnostic period of the plurality of cell groups, and a difference value between the second ratio in the diagnostic period and a second largest value among the plurality of second ratios is greater than or equal to a fifth threshold value.

[0021] A battery diagnosis method according to an embodiment disclosed in the present document may include an operation of acquiring voltage data of a plurality of battery cells included in a battery module in the idle period, an operation of calculating a voltage deviation between adjacent periods from a specified time point at a specified time interval in units of cell groups connected in parallel among the plurality of battery cells based on the voltage data, an operation of calculating an accumulated deviation by cumulatively adding up the voltage deviations in units of the cell groups when a maximum voltage deviation among a plurality of voltage deviations in a target period of the plurality of cell groups is equal to or greater than a first threshold value, and an operation of diagnosing battery cells included in a cell group satisfying a specified condition among the plurality of cell groups as abnormal battery cells based on the voltage deviation and the accumulated deviation.

[0022] In a battery diagnosis method according to an embodiment disclosed in this document, the operation of calculating the cumulative deviation may include an operation of calculating the cumulative deviation by cumulatively adding up the voltage deviations only for a section in which the average value of the plurality of cumulative deviations of the plurality of cell groups is less than a second threshold value.

[0023] A battery diagnosis method according to an embodiment disclosed in the present document may further include an operation of calculating a first ratio by dividing the accumulated deviation by a larger value between the average value of the plurality of accumulated deviations and the second threshold value, for each cell group, and the diagnosing operation may include an operation of diagnosing battery cells included in the cell group that satisfy the specified condition as abnormal battery cells based on the first ratio.

[0024] A battery diagnosis method according to an embodiment disclosed in this document may further include an operation of correcting the first ratio to a second ratio by using an OCV (Open Circuit Voltage) deviation according to a change in SOC (State of Charge) for each cell group, and the diagnosing operation may include an operation of diagnosing battery cells included in a cell group that satisfy the specified condition as abnormal battery cells based on the second ratio.

[0025] A battery diagnosis method according to an embodiment disclosed in the present document may further include an operation of calculating an OCV deviation ratio by dividing the OCV deviation by an average value of a plurality of OCV deviations of the plurality of cell groups, in units of the cell groups, and the operation of correcting the first ratio by a second ratio may include an operation of calculating the second ratio by dividing the first ratio by a larger value between the OCV deviation ratio and a specified value, in units of the cell groups.

[0026] In a battery diagnosis method according to an embodiment disclosed in the present document, the specified condition may include at least one of a first condition in which a difference value between the voltage deviation in the diagnosis period and an average value of the voltage deviations in the diagnosis period of the plurality of cell groups is less than or equal to a third threshold value, a second condition in which the second ratio in the diagnosis period is a maximum value among the plurality of second ratios in the diagnosis period of the plurality of cell groups, a third condition in which the second ratio in the diagnosis period is greater than or equal to a fourth threshold value, or a fourth condition in which the second ratio in the diagnosis period is a maximum value among the plurality of second ratios in the diagnosis period of the plurality of cell groups, and a difference value between the second ratio in the diagnosis period and a second largest value among the plurality of second ratios is greater than or equal to a fifth threshold value.

[0027] According to embodiments disclosed in this document, by diagnosing a battery in which a negative tab short circuit has occurred and / or a battery in which a negative tab short circuit and lithium deposition have occurred, a battery that may subsequently progress to an internal short circuit can be tracked and managed.

[0028] In addition, various effects may be provided, either directly or indirectly, through this document.

[0029] FIG. 1 is a block diagram of a battery diagnostic device according to one embodiment.

[0030] Figure 2 is a block diagram of a production unit in a battery diagnostic device according to one embodiment.

[0031] FIG. 3 is a diagram showing a resting section voltage obtained by a battery diagnostic device according to one embodiment.

[0032] FIG. 4 is a diagram showing a voltage deviation calculated by a battery diagnostic device according to one embodiment.

[0033] FIG. 5 is a diagram showing a cumulative deviation calculated by a battery diagnostic device according to one embodiment.

[0034] FIG. 6 is a diagram showing a second ratio calculated by a battery diagnostic device according to one embodiment.

[0035] Figure 7 is a flowchart of the operation of a battery diagnostic device according to one embodiment.

[0036] Figure 8 is a flowchart of the operation of a battery diagnostic device according to one embodiment.

[0037] Figure 9 is a flowchart illustrating the operation of a battery diagnostic device according to one embodiment.

[0038] Hereinafter, various embodiments of the present invention will be described with reference to the attached drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention encompasses various modifications, equivalents, and / or alternatives of the embodiments.

[0039] The various embodiments and terminology used in this document are not intended to limit the technical features described in this document to specific embodiments, but should be understood to encompass various modifications, equivalents, or alternatives of the embodiments. In connection with the description of the drawings, similar reference numerals may be used to refer to similar or related components. The singular form of a noun corresponding to an item may include one or more of the items, unless the context clearly indicates otherwise.

[0040] In this document, the phrases "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" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", "first", "second", "A", "B", "(a)", or "(b)" may be used merely to distinguish the corresponding element from other corresponding elements, and do not limit the corresponding elements in any other respect (e.g., importance or order) unless specifically stated otherwise.

[0041] In this document, whenever a component (e.g., a first component) is referred to as being “connected,” “coupled,” or “connected,” with or without the terms “functionally” or “communicatively,” or “coupled” or “connected,” it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or via a third component.

[0042] According to various embodiments, each component (e.g., a module or a program) of the above-described components may include one or more entities, and some of the entities may be separated and placed in other components. According to various embodiments, one or more components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., a module or a program) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to various embodiments, the 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.

[0043] Hereinafter, the configurations of the battery diagnostic device will be described with reference to FIGS. 1 and 2.

[0044] Fig. 1 is a block diagram of a battery diagnostic device according to one embodiment. Fig. 2 is a block diagram of a calculation unit in a battery diagnostic device according to one embodiment.

[0045] The battery diagnostic device (101) described below can be implemented as a BMS (Battery Management System) in an electronic device including a battery module (102), and can also be implemented as various external devices such as a server, cloud, charger, or charger / discharger.

[0046] Referring to FIG. 1, the battery diagnostic device (101) may include a communication circuit (110), a sensor (120), a memory (130), and a processor (140). According to an embodiment, the battery diagnostic device (101) illustrated in FIG. 1 may further include at least one component (e.g., a display, an input device, or an output device) other than the components illustrated in FIG. 1, or may omit at least one component (e.g., a sensor (120)) among the components illustrated in FIG. 1.

[0047] According to one embodiment, the battery module (102) includes a plurality of cell groups (150, 160, 170), and each cell group (150, 160, or 170) may include a plurality of battery cells connected in parallel to each other. For example, a first cell group (150) may include a plurality of battery cells (151, 153, 155) connected in parallel to each other, a second cell group (160) may include a plurality of battery cells (161, 163, 165) connected in parallel to each other, and a third cell group (170) may include a plurality of battery cells (171, 173, 175) connected in parallel to each other.

[0048] According to one embodiment, the battery diagnostic device (101) can obtain data related to the status (e.g., voltage, current, or temperature) of a plurality of cell groups (150, 160, 170) included in a battery module (102) using a communication circuit (110) and / or a sensor (120).

[0049] According to one embodiment, the communication circuit (110) establishes a wired communication channel and / or a wireless communication channel between a battery diagnostic device (101) and an electronic device including a battery module (102) and / or a user terminal (103), and transmits and receives data with the electronic device including the battery module (102) and / or the user terminal (103) through the established communication channel. Here, the electronic device including the battery module (102) may be a mobile device (e.g., a mobile phone, a laptop computer, a smart phone, a smart pad), an electric vehicle (e.g., an electric vehicle (EV), a hybrid EV (HEV), a plug-in HEV (PHEV), a fuel cell EV (FCEV)), an energy storage system (ESS), or a battery swapping system (BSS).

[0050] For example, when the battery diagnostic device (101) is implemented as an external device such as a server or a cloud, the battery diagnostic device (101) can obtain data related to the status of a plurality of cell groups (150, 160, 170) from an electronic device including a battery module (102) using a communication circuit (110). In this case, the battery diagnostic device (101) may not include a sensor (120).

[0051] According to one embodiment, the user terminal (103) may be a mobile device (e.g., a mobile phone, a laptop computer, a smart phone, a smart pad), or a personal computer (PC). According to one embodiment, the battery diagnostic device (101) may transmit data related to the diagnostic results for a cell group (150, 160, or 170) to the user terminal (103) using the communication circuit (110).

[0052] According to one embodiment, the sensor (120) can measure status values ​​of a plurality of cell groups (150, 160, 170). For example, when the battery diagnostic device (101) is implemented as a BMS (e.g., a module BMS of the battery module (102)) in an electronic device including a battery module (102), the battery diagnostic device (101) can directly measure status values ​​of a plurality of cell groups (150, 160, 170) using the sensor (120).

[0053] According to one embodiment, the memory (130) may include volatile memory and / or non-volatile memory.

[0054] According to one embodiment, the memory (130) may store data used by at least one component (e.g., processor (140)) of the battery diagnosis device (110). For example, the data may include software (or instructions related thereto), input data, or output data. In one embodiment, the instructions, when executed by the processor (140), may cause the battery abnormality diagnosis device (101) to perform operations defined by the instructions.

[0055] According to one embodiment, the memory (140) may include one or more software (e.g., an acquisition unit (131), a calculation unit (132), a correction unit (133), and a diagnosis unit (134)).

[0056] According to one embodiment, the processor (140) may include a central processing unit, an application processor, a graphics processing unit, a neural processing unit (NPU), an image signal processor, a sensor hub processor, or a communication processor.

[0057] According to one embodiment, the processor (140) may execute software (e.g., an acquisition unit (131), a calculation unit (132), a correction unit (133), and a diagnosis unit (134)) to control at least one other component (e.g., a hardware or software component) of a battery diagnosis device (101) connected to the processor (140) and perform various data processing or operations.

[0058] Hereinafter, with reference to FIGS. 3 to 6, a method for diagnosing a battery diagnostic device (101) through an acquisition unit (131), a calculation unit (132), a correction unit (133), and / or a diagnosis unit (134) is described.

[0059] FIG. 3 is a diagram showing the resting voltage obtained by a battery diagnostic device according to an embodiment. FIG. 4 is a diagram showing the voltage deviation calculated by a battery diagnostic device according to an embodiment. FIG. 5 is a diagram showing the cumulative deviation calculated by a battery diagnostic device according to an embodiment. FIG. 6 is a diagram showing the second ratio calculated by a battery diagnostic device according to an embodiment.

[0060] According to one embodiment, the acquisition unit (131) can acquire idle period voltage data of a plurality of cell groups (150, 160, 170) using the communication circuit (110) and / or the sensor (120). Here, the idle period may mean an idle period after charging or an idle period after discharging of the plurality of cell groups (150, 160, 170). For example, the acquisition unit (131) can acquire idle period voltage data of a first cell group (150), a second cell group (160), and a third cell group (170) such as the graph (300) of FIG. 3.

[0061] According to one embodiment, the deviation calculation unit (210) included in the calculation unit (132) may calculate a voltage deviation at a specified time interval from a specified time point for each cell group (150, 160, or 170) based on the voltage data acquired by the acquisition unit (131). Here, the voltage deviation may mean a voltage deviation between adjacent periods of the cell groups (150, 160, or 170). The adjacent period may mean, for example, a period for which voltage deviation is calculated and a period immediately preceding the target period. That is, the voltage deviation may mean a difference value between the voltage of the cell group (150, 160, or 170) in the target period and the voltage of the cell group (150, 160, or 170) in the immediately preceding period, which is the specified time before the target period.

[0062] For example, the deviation calculation unit (210) can calculate the voltage deviation between adjacent cycles of the first cell group (150), the second cell group (160), and the third cell group (170), as shown in the graph (400) of FIG. 4, at 200-second intervals starting 600 seconds after entering the idle period based on idle period voltage data, as shown in the graph (300) of FIG. 3.

[0063] According to one embodiment, the cumulative calculation unit (220) included in the calculation unit (132) can cumulatively add up the voltage deviations calculated by the deviation calculation unit (210) by cell group (150, 160, or 170) to calculate the cumulative deviation.

[0064] According to one embodiment, the cumulative calculation unit (220) can calculate cumulative deviations corresponding to each of the first cell group (150), the second cell group (160), and the third cell group (170), as in the graph (500) of FIG. 5, based on voltage deviation data such as the graph (400) of FIG. 4.

[0065] According to one embodiment, the cumulative calculation unit (220) can calculate the cumulative deviation by cumulatively adding up the voltage deviations by cell group (150, 160, or 170) only in a period in which the maximum voltage deviation among the voltage deviations of the plurality of cell groups (150, 160, 170) calculated by the deviation calculation unit (210) is greater than or equal to a first threshold value (e.g., 0.5 mV).

[0066] For example, the cumulative calculation unit (220) may calculate the cumulative deviation by cumulatively adding up the voltage deviations in the target period by cell group (150, 160, or 170) only when the maximum voltage deviation among the plurality of voltage deviations in the target period of the calculation of the plurality of cell groups (150, 160, 170) is greater than or equal to the first threshold value. That is, in this case, the cumulative deviation in the target period may be an updated value obtained by adding the voltage deviation in the target period to the cumulative deviation in the previous period.

[0067] As another example, the cumulative calculation unit (220) may exclude the voltage deviation in the target period from the cumulative summation target if the maximum voltage deviation among the plurality of voltage deviations in the target period of calculation of the plurality of cell groups (150, 160, 170) is less than the first threshold value. That is, in this case, the cumulative deviation in the target period may be the same value as the cumulative deviation in the previous period.

[0068] According to one embodiment, the first threshold value may be a value related to a noise level occurring during voltage measurement. That is, the cumulative calculation unit (220) may improve diagnostic accuracy by not accumulating voltage deviations in the cumulative deviations in a period in which the voltage measurement noise level is above the threshold level.

[0069] According to one embodiment, the cumulative calculation unit (220) may cumulatively add up voltage deviations for each cell group (150, 160, or 170) only for a section in which the average value of the plurality of cumulative deviations of the plurality of cell groups (150, 160, 170) is less than a second threshold value (e.g., 1 mV), thereby calculating the cumulative deviation. Here, the second threshold value may be a value set to prevent the cumulative deviation from continuously increasing without limit.

[0070] For example, in the case of a target period in which the average value of the plurality of accumulated deviations calculated up to the previous period is greater than or equal to the second threshold value, the cumulative calculation unit (220) may no longer add up the voltage deviations and may calculate the cumulative deviation calculated up to the previous period as the final cumulative deviation corresponding to the corresponding section. In addition, the cumulative calculation unit (220) may calculate the final cumulative deviation corresponding to the next section by accumulating the voltage deviations from the target period to the previous period of another period in which the average value is greater than or equal to the second threshold value.

[0071] According to one embodiment, the ratio calculation unit (230) included in the calculation unit (132) can calculate a first ratio for each cell group (150, 160, or 170) using the cumulative deviation calculated by the cumulative calculation unit (220). Here, the first ratio can be a value obtained by dividing the cumulative deviation of the cell group (150, 160, or 170) by a larger value between the average value of the plurality of cumulative deviations of the plurality of cell groups (150, 160, 170) and the second threshold value.

[0072] According to one embodiment, the correction unit (133) may correct the first ratio calculated by the ratio calculation unit (230) to a second ratio by using the OCV (Open Circuit Voltage) deviation according to the SOC (State of Charge) change. Here, the OCV deviation may mean an OCV difference value of a cell group (150, 160, or 170) according to a SOC change (e.g., a 1% SOC change) in a SOC range specified for each cell group (150, 160, or 170).

[0073] Since the resting voltage fluctuations of a battery can be influenced by the slope of the OCV voltage curve, the resting voltage deviations of cell groups within the same battery module may differ depending on the OCV deviation. Accordingly, by compensating the first ratio for cell group-specific diagnosis using the OCV deviation of each cell group, the diagnostic accuracy can be improved.

[0074] According to one embodiment, the correction unit (133) may calculate an OCV deviation ratio by dividing the OCV deviation by an average value of a plurality of OCV deviations of a plurality of cell groups (150, 160, 170) in units of cell groups (150, 160, or 170). The correction unit (133) may calculate a second ratio by dividing the first ratio calculated by the ratio calculation unit (230) by a larger value between the OCV deviation ratio and a specified value (e.g., 1) in units of cell groups (150, 160, or 170).

[0075] For example, the correction unit (133) can calculate the second ratio of the first cell group (150), the second cell group (160), and the third cell group (170) as in the graph (600) of FIG. 6.

[0076] According to one embodiment, the diagnostic unit (134) can diagnose an abnormality in the cell group (150, 160, or 170) based on at least one of 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).

[0077] According to one embodiment, the diagnostic unit (134) can diagnose battery cells included in a cell group (150, 160, or 170) that satisfies a specified condition among a plurality of cell groups (150, 160, 170) as abnormal battery cells.

[0078] According to one embodiment, the specified condition may include a first condition in which a difference value between a voltage deviation calculated by the deviation calculation unit (210) in the diagnosis cycle and an average value of a plurality of voltage deviations calculated by the deviation calculation unit (210) in the diagnosis cycle of the plurality of cell groups (150, 160, 170) is less than or equal to a third threshold value (e.g., 10 mV).

[0079] 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 the plurality of second ratios corrected by the correction unit (133) in the diagnostic cycle of the plurality of cell groups (150, 160, 170).

[0080] According to one embodiment, the specified condition 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 value (e.g., 1.5).

[0081] According to one embodiment, the specified condition may include a fourth condition in which the second ratio corrected by the correction unit (133) in the diagnosis period is the maximum value among the plurality of second ratios corrected by the correction unit (133) in the diagnosis period of the plurality of cell groups (150, 160, 170), and a difference value between the second ratio in the diagnosis period and the second largest value among the plurality of second ratios is equal to or greater than a fifth threshold value (0.5).

[0082] According to one embodiment, the diagnostic unit (134) may diagnose battery cells included in a cell group (150, 160, or 170) that satisfy all conditions included in the specified conditions as abnormal battery cells. According to another embodiment, the diagnostic unit (134) may also diagnose battery cells included in a cell group (150, 160, or 170) that satisfy a specified number of conditions among at least one condition included in the specified conditions among a plurality of cell groups (150, 160, 170) as abnormal battery cells.

[0083] Fig. 7 is a flowchart illustrating the operation of a battery diagnostic device according to an embodiment. Fig. 7 may be an explanation of the operation of the battery diagnostic device (101) of Fig. 1, and may be explained using the configuration of Fig. 1.

[0084] The embodiment illustrated in FIG. 7 is only one embodiment, and the order of steps according to various embodiments of the present invention may be different from that illustrated in FIG. 7, and some of the steps illustrated in FIG. 7 may be omitted, the order between steps may be changed, or steps may be merged.

[0085] Referring to FIG. 7, in operation 705, the battery diagnostic device (101) can obtain idle period voltage data of a plurality of cell groups (150, 160, 170). Here, the idle period may mean a post-charge idle period or a post-discharge idle period of the plurality of cell groups (150, 160, 170).

[0086] In operation 710, the battery diagnostic device (101) can calculate a voltage deviation at a specified time interval from a specified time point for each cell group (150, 160, or 170) based on the voltage data acquired in operation 705. Here, the voltage deviation may mean a voltage deviation between adjacent periods of the cell groups (150, 160, or 170). The adjacent period may mean, for example, a period for which voltage deviation is calculated and a period immediately preceding the target period. That is, the voltage deviation may mean a difference value between the voltage of the cell group (150, 160, or 170) in the target period and the voltage of the cell group (150, 160, or 170) in the immediately preceding period, which is the specified time before the target period.

[0087] In operation 715, the battery diagnostic device (101) can identify whether the maximum voltage deviation among the plurality of voltage deviations of the plurality of cell groups (150, 160, 170) produced in operation 710 is greater than or equal to a first threshold value (e.g., 0.5 mV).

[0088] If the maximum voltage deviation is identified as being less than the first threshold value in operation 715 ('NO'), the battery diagnostic device (101) may re-perform operation 710 in the next cycle after the specified time has elapsed from the target cycle. That is, in this case, the battery diagnostic device (101) may calculate the voltage deviation between the next cycle and the target cycle in the next cycle.

[0089] If it is identified that the maximum voltage deviation is greater than or equal to the first threshold value in operation 715 ('YES'), in operation 720, the battery diagnostic device (101) may cumulatively add up the voltage deviations calculated in operation 710 by cell group (150, 160, or 170) to calculate an accumulated deviation. For example, the battery diagnostic device (101) may add up the voltage deviation calculated in the target period to the cumulative deviation calculated in the previous period to calculate the cumulative deviation in the target period.

[0090] In operation 725, the battery diagnostic device (101) can identify whether the average value of the plurality of accumulated deviations of the plurality of cell groups (150, 160, 170) produced in operation 720 is greater than or equal to a second threshold value (e.g., 1 mV).

[0091] If the average value is identified as being less than the second threshold value in operation 725 ('NO'), the battery diagnostic device (101) may re-perform operation 710 in the next cycle after the specified time has elapsed from the target cycle. That is, in this case, the battery diagnostic device (101) may calculate the voltage deviation between the next cycle and the target cycle in the next cycle.

[0092] If the average value is identified as being equal to or greater than the second threshold value in operation 725 ('YES'), in operation 730, the battery diagnostic device (101) may diagnose an abnormality in the 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 also diagnose an abnormality in the cell group (150, 160, or 170) further based on the first ratio and / or the second ratio, which will be described later with reference to FIG. 8.

[0093] According to one embodiment, the battery diagnostic device (101) can diagnose battery cells included in a cell group (150, 160, or 170) that satisfies a specified condition among a plurality of cell groups (150, 160, 170) as abnormal battery cells. Here, the specified condition may include the first to fourth conditions described above in FIG. 1.

[0094] According to one embodiment, the battery diagnostic device (101) can diagnose battery cells included in a cell group (150, 160, or 170) that satisfy all conditions included in the specified conditions as abnormal battery cells. With regard to the embodiment, a detailed description can be made through FIG. 9, which will be described later.

[0095] According to another embodiment, the battery diagnostic device (101) may diagnose battery cells included in a cell group (150, 160, or 170) that satisfies a specified number of conditions among at least one of the conditions included in the specified conditions among a plurality of cell groups (150, 160, 170) as abnormal battery cells.

[0096] Fig. 8 is a flowchart illustrating the operation of a battery diagnostic device according to an embodiment. Fig. 8 may be an explanation of the operation of the battery diagnostic device (101) of Fig. 1, and may be explained using the configuration of Fig. 1.

[0097] The embodiment illustrated in FIG. 8 is only one embodiment, and the order of steps according to various embodiments of the present invention may be different from that illustrated in FIG. 8, and some of the steps illustrated in FIG. 8 may be omitted, the order between steps may be changed, or steps may be merged.

[0098] Referring to FIG. 8, in operation 805, the battery diagnostic device (101) may calculate a first ratio for each cell group (150, 160, or 170). According to one embodiment, the battery diagnostic device (101) may calculate the first ratio using the cumulative deviation calculated in operation 720 of FIG. 7. Here, the first ratio may be a value obtained by dividing the cumulative deviation of the cell group (150, 160, or 170) by a larger value between an average value of a plurality of cumulative deviations of a plurality of cell groups (150, 160, 170) and the second threshold value.

[0099] In operation 810, the battery diagnostic device (101) can correct the first ratio calculated in operation 805 to a second ratio by using the OCV deviation according to the SOC change. Here, the OCV deviation may mean an OCV difference value of a cell group (150, 160, or 170) according to a SOC change (e.g., a 1% SOC change) in a SOC range specified for each cell group (150, 160, or 170).

[0100] Since the resting voltage fluctuations of a battery can be influenced by the slope of the OCV voltage curve, the resting voltage deviations of cell groups within the same battery module may differ depending on the OCV deviation. Accordingly, by compensating the first ratio for cell group-specific diagnosis using the OCV deviation of each cell group, the diagnostic accuracy can be improved.

[0101] According to one embodiment, the battery diagnostic device (101) may calculate an OCV deviation ratio by dividing the OCV deviation by an average value of the OCV deviations of the plurality of cell groups (150, 160, 170) in units of cell groups (150, 160, or 170). The battery diagnostic device (101) may calculate a second ratio by dividing the first ratio calculated in operation 805 by a larger value between the OCV deviation ratio and a specified value (e.g., 1) in units of cell groups (150, 160, or 170).

[0102] At operation 815, the battery diagnostic device (101) can diagnose an abnormality in the cell group (150, 160, or 170) based on the second ratio corrected at operation 815.

[0103] According to one embodiment, the battery diagnostic device (101) can diagnose battery cells included in a cell group (150, 160, or 170) that satisfies a specified condition among a plurality of cell groups (150, 160, 170) as abnormal battery cells. Here, the specified condition may include the first to fourth conditions described above in FIG. 1.

[0104] According to one embodiment, the battery diagnostic device (101) can diagnose battery cells included in a cell group (150, 160, or 170) that satisfy all conditions included in the specified conditions as abnormal battery cells. With regard to the embodiment, a detailed description can be made through FIG. 9, which will be described later.

[0105] According to another embodiment, the battery diagnostic device (101) may diagnose battery cells included in a cell group (150, 160, or 170) that satisfies a specified number of conditions among at least one of the conditions included in the specified conditions among a plurality of cell groups (150, 160, 170) as abnormal battery cells.

[0106] Fig. 9 is a flowchart illustrating the operation of a battery diagnostic device according to an embodiment. Fig. 9 may be an explanation of the operation of the battery diagnostic device (101) of Fig. 1, and may be explained using the configuration of Fig. 1.

[0107] The embodiment illustrated in FIG. 9 is only one embodiment, and the order of steps according to various embodiments of the present invention may be different from that illustrated in FIG. 9, and some of the steps illustrated in FIG. 9 may be omitted, the order between steps may be changed, or steps may be merged.

[0108] Referring to FIG. 9, in operation 905, the battery diagnostic device (101) can identify whether a difference value between a voltage deviation in a diagnostic cycle of a diagnostic target cell group (150, 160, or 170) and an average value of a plurality of voltage deviations in diagnostic cycles of a plurality of cell groups (150, 160, 170) is less than or equal to a third threshold value (e.g., 10 mV).

[0109] If the difference value is identified as exceeding the third threshold value in operation 905 ('NO'), in operation 910, the battery diagnostic device (101) can diagnose the diagnosis target cell group (150, 160, or 170) as a normal cell group.

[0110] If the difference value is identified as being less than or equal to the third threshold value in operation 905 ('YES'), 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) to be diagnosed corresponds to a maximum value among the plurality of second ratios in the diagnostic cycles of the plurality of cell groups (150, 160, 170).

[0111] If the second ratio of the diagnosis target cell group (150, 160, or 170) is identified as not being the maximum value in operation 915 ('NO'), in operation 910, the battery diagnosis device (101) can diagnose the diagnosis target cell group (150, 160, or 170) as a normal cell group.

[0112] If the second ratio of the diagnosis target cell group (150, 160, or 170) is identified as being equal to the maximum value in operation 915 ('YES'), then in operation 920, the battery diagnosis device (101) can identify whether the second ratio in the diagnosis cycle of the diagnosis target cell group (150, 160, or 170) is equal to or greater than the fourth threshold value (e.g., 1.5).

[0113] If the second ratio of the diagnosis target cell group (150, 160, or 170) is identified as being less than the fourth threshold value in operation 920 ('NO'), then in operation 910, the battery diagnosis device (101) can diagnose the diagnosis target cell group (150, 160, or 170) as a normal cell group.

[0114] If the second ratio of the diagnosis target cell group (150, 160, or 170) is identified as being greater than or equal to the fourth threshold value in operation 920 ('YES'), then in operation 925, the battery diagnosis device (101) can identify whether a difference value between the second ratio in the diagnosis cycle of the diagnosis target cell group (150, 160, or 170) and a second largest value among the plurality of second ratios in the diagnosis cycles of the plurality of cell groups (150, 160, 170) is greater than or equal to the fifth threshold value (e.g., 0.5).

[0115] If the difference value is identified as being less than the fifth threshold value in operation 925 ('NO'), in operation 910, the battery diagnostic device (101) can diagnose the diagnosis target cell group (150, 160, or 170) as a normal cell group.

[0116] If the difference value is identified as being greater than or equal to the fifth threshold value in operation 925 ('YES'), in operation 930, the battery diagnostic device (101) can diagnose the diagnosis 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 diagnosis target cell group (150, 160, or 170) diagnosed as an abnormal cell group as abnormal battery cells.

[0117] The terms "include," "comprise," or "have" used herein, unless otherwise specifically stated, imply that the corresponding component may be included, and therefore should be interpreted to include other components rather than to exclude other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document pertain, unless otherwise defined. Commonly used terms, such as terms defined in dictionaries, should be interpreted to be consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense, unless explicitly defined in this document.

Claims

1. An acquisition unit that acquires voltage data in a resting period of a plurality of battery cells included in a battery module; Based on the voltage data, a deviation calculation unit that calculates a voltage deviation between adjacent cycles at a specified time interval from a specified time point in units of cell groups connected in parallel among the plurality of battery cells; An accumulation calculation unit that, if the maximum voltage deviation among the plurality of voltage deviations in the target cycle of the plurality of cell groups is greater than or equal to a first threshold value, calculates an accumulated deviation by cumulatively adding up the voltage deviations for each cell group; and A battery diagnosis device, comprising a diagnosis unit that diagnoses battery cells included in a cell group satisfying a specified condition among the plurality of cell groups as abnormal battery cells based on the voltage deviation and the accumulated deviation.

2. In claim 1, The above-mentioned cumulative calculation unit is a battery diagnostic device that calculates the cumulative deviation by cumulatively adding up the voltage deviations only for a section in which the average value of the plurality of cumulative deviations of the plurality of cell groups is less than the second threshold value.

3. In claim 2, In the above cell group unit, it further includes a ratio calculation unit that calculates a first ratio by dividing the accumulated deviation by a larger value between the average value of the plurality of accumulated deviations and the second threshold value, A battery diagnostic device, wherein the diagnostic unit diagnoses battery cells included in a cell group satisfying the specified condition based on the first ratio as abnormal battery cells.

4. In claim 3, In the above cell group unit, it further includes a correction unit that corrects the first ratio to a second ratio by using the OCV (Open Circuit Voltage) deviation according to the SOC (State of Charge) change, A battery diagnostic device, wherein the diagnostic unit diagnoses battery cells included in a cell group satisfying the specified condition as abnormal battery cells based on the second ratio.

5. In claim 4, The above correction part, For each cell group, an OCV deviation ratio is calculated by dividing the OCV deviation by the average value of multiple OCV deviations of the multiple cell groups, A battery diagnostic device that calculates the second ratio by dividing the first ratio by a larger value between the OCV deviation ratio and a specified value, for each cell group.

6. In claim 4, A battery diagnostic device, wherein the above-mentioned specified condition includes a first condition in which a difference value between the voltage deviation in the diagnostic period and an average value of the plurality of voltage deviations in the diagnostic period of the plurality of cell groups is less than or equal to a third threshold value.

7. In claim 4, A battery diagnostic device, wherein the above-mentioned specified condition includes a second condition in which the second ratio in the diagnostic period is the maximum value among a plurality of second ratios in the diagnostic period of the plurality of cell groups.

8. In claim 4, A battery diagnostic device, wherein the above-mentioned specified conditions include a third condition in which the second ratio in the diagnostic cycle is greater than or equal to a fourth threshold value.

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

10. An operation of acquiring voltage data in the resting period of a plurality of battery cells included in a battery module; An operation of calculating a voltage deviation between adjacent cycles at a specified time interval from a specified point in time, based on the voltage data, for each group of cells connected in parallel among the plurality of battery cells; An operation of calculating an accumulated deviation by cumulatively adding up the voltage deviations in units of the cell groups when the maximum voltage deviation among the plurality of voltage deviations in the target cycle of the plurality of cell groups is greater than or equal to a first threshold value; and A battery diagnosis method, comprising an operation of diagnosing battery cells included in a cell group satisfying a specified condition among the plurality of cell groups as abnormal battery cells based on the voltage deviation and the accumulated deviation.

11. In claim 10, A battery diagnosis method, wherein the operation of calculating the cumulative deviation includes an operation of calculating the cumulative deviation by cumulatively adding up the voltage deviations only for a section in which the average value of the plurality of cumulative deviations of the plurality of cell groups is less than a second threshold value.

12. In claim 11, In the above cell group unit, further comprising an operation of calculating a first ratio by dividing the accumulated deviation by a larger value between the average value of the plurality of accumulated deviations and the second threshold value, A battery diagnosis method, wherein the above-mentioned diagnosing operation includes an operation of diagnosing battery cells included in a cell group satisfying the specified condition as abnormal battery cells based on the first ratio.

13. In claim 12, In the above cell group unit, an operation of correcting the first ratio to a second ratio by using the OCV (Open Circuit Voltage) deviation according to the SOC (State of Charge) change is further included, A battery diagnosis method, wherein the above-mentioned diagnosing operation includes an operation of diagnosing battery cells included in a cell group satisfying the specified condition as abnormal battery cells based on the second ratio.

14. In claim 13, In the above cell group unit, the operation of calculating an OCV deviation ratio by dividing the OCV deviation by an average value of a plurality of OCV deviations of the plurality of cell groups is further included, A battery diagnosis method, wherein the operation of correcting the first ratio to a second ratio includes an operation of calculating the second ratio by dividing the first ratio by a larger value between the OCV deviation ratio and a specified value, for each cell group.

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

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