Abnormal cell diagnosis apparatus and method using cell voltage deviation

Abstract

Disclosed herein are an abnormal cell diagnosis apparatus and method using a cell voltage deviation, which uses a method of comparing with an intermediate value of all battery cell data to acquire battery cell information according to a point in time and a situation in which a battery system is operated and using a voltage difference to find an abnormal value, and it increases the efficiency of abnormal cell detection by applying conditions according to the characteristics of the state of charge in each section. The abnormal cell diagnosis apparatus includes: a voltage measurement module configured to measure an initial open circuit voltage (OCV) or closed circuit voltage (CCV) of each battery cell; a timer configured to count a minimum rest time of each battery cell; and a processor configured to calculate a quartile distance (IQR) based on the initial OCV or CCV depending on whether the minimum rest time is satisfied, set an abnormal value criterion, and detect an abnormal cell based on the set abnormal value criterion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0030745, filed on March 4, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Aspects of the embodiments of the present disclosure relate to an apparatus and method capable of diagnosing an abnormal cell using cell voltage deviation. Background Art

[0004] The battery management system (BMS) has the function of evaluating the battery charge and discharge status and continuously measuring the temperature and battery voltage to detect and control faults. The purpose of this function is to detect abnormal phenomena from battery cells in advance and prevent dangerous situations.

[0005] There is a high probability of a problem occurring in an abnormal cell, but there are cases where it cannot be pinned down to specific conditions. Numerous tests are conducted to identify these specific conditions, but most test results fall within a wide range of values ​​that can also be found in normal cells, and these values ​​cannot be used as absolute criteria for a problem.

[0006] When the causes of a problem are diverse and the exact cause cannot be identified, abnormal monomers can be detected by a set threshold by assuming a worst-case scenario, but the probability of over-detection of normal monomers determined by the threshold may be accompanied by problems in the monomer detection method.

[0007] The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute related (or prior) art. Summary of the Invention

[0008] The present invention aims to provide an abnormal cell diagnosis device and method using cell voltage deviation, which involves using comparison with a median value of all battery cell data to obtain battery cell information according to the time point and situation in which the battery system is operated and using the voltage difference between cells to thereby discover abnormal values, and which improves the efficiency of abnormal cell detection by applying conditions according to the characteristics of the charge state in each interval.

[0009] However, the objects that the present invention is intended to achieve are not limited to the above-mentioned objects, and other objects that are not described can be clearly understood by those skilled in the art from the following description.

[0010] According to aspects of the present invention, there is provided an abnormal cell diagnostic device using cell voltage deviation, which includes: a voltage measurement module configured to measure an initial open circuit voltage (OCV) or closed circuit voltage (CCV) of each battery cell; a timer configured to count a minimum rest time for each battery cell; and a processor configured to calculate an interquartile range (IQR) based on the initial OCV or CCV depending on whether the minimum rest time is met, set an abnormal value standard, and detect abnormal cells based on the set abnormal value standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following drawings attached to this specification illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe various aspects and features of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the accompanying drawings, in which:

[0012] Figure 1 is a diagram illustrating an example of a battery module according to one embodiment of the present invention;

[0013] Figure 2 is a block diagram for describing an abnormal cell diagnosis apparatus using cell voltage deviation according to one embodiment of the present invention;

[0014] Figures 3 to 5 is an exemplary diagram for describing a method for setting an outlier criterion according to one embodiment of the present invention;

[0015] Figure 6 is a flowchart for describing an abnormal cell diagnosis method using cell voltage deviation according to one embodiment of the present invention; and

[0016] Figure 7 is a flowchart for describing an abnormal cell diagnosis method using cell voltage deviation according to another embodiment of the present invention. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be interpreted as limited to the usual or dictionary meanings, but should be interpreted as meanings and concepts consistent with the technical idea of ​​the present disclosure based on the principle that the inventor can be his / her own lexicon compiler to appropriately define the concept of the term so as to best explain his / her invention.

[0018] The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure and do not represent all technical ideas, aspects and features of the present disclosure. Accordingly, it should be understood that at the time of filing this application, there may be various equivalents and modifications that can replace or modify the embodiments described herein.

[0019] It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or one or more intervening elements or layers may be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers. For example, when a first element is described as being “coupled to” or “connected to” a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0020] In each figure, for clarity of illustration, the sizes of various elements, layers, etc. can be magnified. The same figure mark represents the same element. As used in this article, the term "and / or" includes any and all combinations of one or more of the associated listed items. Further, when describing an embodiment of the present disclosure, the use of "can" relates to "one or more embodiments of the present disclosure". When before / after a list of elements, expressions such as "at least one of ... " and "any one of ... " modify the entire list of elements and do not modify the individual elements of the list. When using phrases such as "at least one of A, B and C", "at least one selected from the group of A, B and C" or "at least one selected from the middle of A, B and C" to represent a list of elements A, B and C, the phrase can refer to any and all suitable combinations or subsets of A, B and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used in this article, the terms "using", "being used" and "being used" can be considered to be synonymous with the terms "utilizing", "being utilized" and "being utilized" respectively. As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than terms of degree, and are intended to take into account the inherent variations in measurements or calculations that would be recognized by one of ordinary skill in the art.

[0021] It will be understood that although the terms first, second, third, etc. can be used in this article to describe various elements, components, regions, layers and / or intervals, these elements, components, regions, layers and / or intervals should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or interval from another element, component, region, layer or interval. Therefore, the first element, component, region, layer or interval discussed below can be referred to as the second element, component, region, layer or interval without departing from the teachings of the exemplary embodiments.

[0022] For ease of description, spatially relative terms such as "below," "beneath," "lower," "above," and "upper" may be used herein to describe the relationship of one element or feature to another element or feature illustrated in the figures. It will be understood that, in addition to the orientation depicted in the figures, the spatially relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as being "below" or "below" other elements or features will then be oriented "above" or "on" the other elements or features. Thus, the term "below" can encompass both the above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0023] The terms used in this article are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used in this article, the singular form "a" and "an" are also intended to include the plural form, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "comprise" and / or "include" and their variations specify the presence of the features, integers, steps, operations, elements and / or parts described, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0024] In addition, any numerical range disclosed and / or recorded in this article is intended to include all sub-ranges of the same numerical precision included in the recorded range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the minimum value of 1.0 recorded and the maximum value of 10.0 recorded (and including the minimum value of 1.0 recorded and the maximum value of 10.0 recorded), that is, there is a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit recorded in this article is intended to include all lower numerical limits contained therein, and any minimum numerical limit recorded in this specification is intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to amend this specification (including claims) to explicitly record any sub-range contained in the range explicitly recorded in this article.

[0025] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same." Thus, the phrase "substantially the same" may include variations that are considered low in the art, for example, 5% or less. Additionally, when a parameter is referred to as uniform in a given area, this may mean that it is uniform with respect to the average value.

[0026] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0027] When any element is referred to as being arranged (or located or positioned) “on (or under)” or “on (or under)” a component, this may mean that the any element is placed in contact with the upper (or lower) surface of the component, and may also mean that another component may be inserted between the component and any element arranged (or located or positioned) on (or under) the component.

[0028] In addition, it will be understood that when an element is referred to as being “coupled,” “linked,” or “connected” to another element, the elements may be directly “coupled,” “linked,” or “connected” to each other, or intervening elements may exist between them through which the element may be “coupled,” “linked,” or “connected” to the other element. In addition, when a part is referred to as being “electrically coupled” to another part, the part may be directly connected to the other part, or intervening parts may exist between them such that the part and the other part are indirectly connected to each other.

[0029] Throughout the specification, when "A and / or B" is stated, this means A, B, or A and B, unless otherwise stated. That is, "and / or" includes any and all combinations of the listed items. When "C to D" is stated, this means C or greater and D or less, unless otherwise stated.

[0030] Figure 1 is a diagram illustrating an example of a battery module according to one embodiment of the present invention.

[0031] refer to Figure 1 The battery module 100 according to the present invention includes a plurality of battery cells 10 provided with terminals 11 and 12 and arranged in one direction, a connection tab 20 connecting the battery cell 10a to the adjacent battery cell 10b, and a protection circuit module 30 having one end connected to the connection tab 20. The protection circuit module 30 may be a battery management system (BMS). In addition, the connection tab 20 includes a main body that contacts the terminals 11 and 12 between the adjacent battery cells 10a and 10b and an extension extending from the main body to connect to the protection circuit module 30. The connection tab 20 may be a bus bar.

[0032] First, the battery cell 10 may be formed of a battery case and an electrode assembly and an electrolyte housed in the battery case. The electrode assembly and the electrolyte undergo an electrochemical reaction to generate energy. Terminals 11 and 12 electrically connected to the connecting tab 20 and an exhaust port 13 serving as an exhaust passage for the gas generated inside the battery cell 10 may be provided on one side of the battery cell 10. The terminals 11 and 12 of the battery cell 10 may be a positive electrode terminal 11 and a negative electrode terminal 12 having different polarities, and the terminals 11 and 12 of adjacent battery cells 10a and 10b may be electrically connected in series or in parallel through the connecting tab 20. Meanwhile, although an example of series connection has been described, the present invention is not limited to this structure, and of course, various connection structures may be adopted as needed. In addition, the number and arrangement of the battery cells 10 are not limited to Figure 1 The structure shown in , and can be changed as needed.

[0033] A plurality of battery cells 10 may be arranged in a direction such that the wide surfaces of the battery cells 10 face each other, and the arranged plurality of battery cells 10 may be fixed by housings 61, 62, 63, and 64. The housings 61, 62, 63, and 64 may include a pair of end plates 61 and 62 facing the wide surfaces of the battery cells 10, and a side plate 63 and a bottom plate 64 connecting the pair of end plates 61 and 62. The side plate 63 may support the side surfaces of the battery cells 10, and the bottom plate 64 may support the bottom surfaces of the battery cells 10. In addition, the pair of end plates 61 and 62, the side plates 63, and the bottom plate 64 may be connected by members such as bolts 65.

[0034] Electronic components and a protective circuit may be mounted on the protective circuit module 30, and the protective circuit module 30 may be electrically connected to the connection tab 20. The protective circuit module 30 may include a first protective circuit module 30a and a second protective circuit module 30b extending from different positions in the direction in which the plurality of battery cells 10 are arranged. In this case, the first protective circuit module 30a and the second protective circuit module 30b may be spaced apart by a predetermined distance and positioned parallel to each other so that each of the first protective circuit module 30a and the second protective circuit module 30b can be electrically connected to an adjacent connection tab 20. For example, the first protective circuit module 30a may be formed to extend on one upper side of the plurality of battery cells 10 in the direction in which the plurality of battery cells 10 are arranged, and the second protective circuit module 30b may extend on the other upper side of the plurality of battery cells 10 in the direction in which the plurality of battery cells 10 are arranged. The second protective circuit module 30b may be positioned a predetermined distance apart from the first protective circuit module 30a and arranged parallel to the first protective circuit module 30a, with the vent 13 interposed therebetween.

[0035] In this way, the two protection circuit modules are arranged in parallel and separated from each other in the direction in which the multiple battery cells are arranged, so as to minimize the area of ​​the printed circuit board (PCB) constituting the protection circuit module. The protection circuit module is formed by two protection circuit modules in order to minimize unnecessary PCB area. In addition, the first protection circuit module 30a and the second protection circuit module 30b can be connected to each other by a conductive connecting member 50. In this case, one side of the connecting member 50 is connected to the first protection circuit module 30a, and the other side thereof is connected to the second protection circuit module 30b, so that an electrical connection can be made between the two protection circuit modules. The connection can be performed by any one of welding, resistance welding, laser welding and projection welding.

[0036] Alternatively, the connecting member 50 may be, for example, an electrical wire. Furthermore, the connecting member 50 may be made of an elastic or flexible material. The connecting member 50 can be used to check and manage the voltage, temperature, and current of the multiple battery cells 10. Specifically, information such as voltage, current, and temperature received by the first protection circuit module from adjacent connection tabs, as well as information such as voltage, current, and temperature received by the second protection circuit module from adjacent connection tabs, can be integrated and managed by the protection circuit modules via the connecting member.

[0037] In addition, when the battery cell 10 swells, the impact is absorbed by the elasticity or flexibility of the connection member 50 , so that the first and second protection circuit modules 30 a and 30 b are prevented from being damaged.

[0038] In addition, the shape and structure of the connecting member 50 are not limited to Figure 1 Those shown in .

[0039] In this manner, since the protection circuit module 30 is provided as a first protection circuit module 30a and a second protection circuit module 30b, the area of ​​the PCB constituting the protection circuit module can be minimized, thereby ensuring space inside the battery module. This not only improves operating efficiency by connecting the connection tab 20 to the protection circuit module 30, but also makes it easier to perform repairs when an abnormality is detected in the battery module.

[0040] Figure 2 is a block diagram for describing an abnormal cell diagnosis apparatus using cell voltage deviation according to one embodiment of the present invention, and Figures 3 to 5 is an exemplary diagram for describing a method for setting an outlier criterion according to an embodiment of the present invention.

[0041] refer to Figure 2 An abnormal cell diagnosis apparatus 200 using cell voltage deviation according to an embodiment of the present invention may include a voltage measurement module 210 , a timer 220 , and a processor 230 .

[0042] The voltage measuring module 210 may measure an initial open circuit voltage (OCV) or closed circuit voltage (CCV) of each battery cell. For this purpose, the voltage measuring module 210 may include a voltage sensor.

[0043] The timer 220 may count the minimum rest time of each battery cell, where the minimum rest time may be preset to, for example, two hours.

[0044] The processor 230 can basically detect outliers in the voltage distribution of a single battery cell using the interquartile range (IQR). The processor 230 can distinguish between an idle state (battery idle mode) and a charging state (battery charging mode), and add activation conditions and conditions for identification to supplement the IQR method.

[0045] The processor 230 may calculate the IQR based on the initial OCV or CCV depending on whether the minimum rest time is met, and set an abnormal value standard for detecting abnormal monomers. Figures 3 to 5 Describes the process of setting outlier criteria based on battery idle patterns and battery charging patterns.

[0046] In battery idle mode, processor 230 can detect abnormal values ​​when the minimum rest time is met to achieve stable voltage. In this case, the sensing circuit used for measurement should be intact, and the voltage and temperature of each cell can be measured before the high voltage is connected. Processor 230 can calculate the mean value, IQR, and abnormal value criteria for the voltage of the entire battery pack based on the measured voltages.

[0047] To this end, when the minimum rest time is satisfied, the processor 230 may calculate the IQR based on the initial OCV and set an abnormal value standard for detecting an abnormal cell in the battery idle mode.

[0048] Specifically, when the time counted by the timer 220 exceeds the minimum rest time (for example, two hours), the Figure 3 As shown in , the processor 230 can obtain the median value of the voltage of the entire battery pack based on the initial OCV, and calculate the IQR based on the initial OCV based on the first quartile Q1 and the third quartile Q3. The processor 230 can use the calculated IQR to set an abnormal value standard for detecting abnormal cells in the battery idle state.

[0049] In other words, the abnormality value criterion for detecting an abnormal cell in the battery idle state may be set to the calculation result value of the following Equation 1.

[0050] [Equation 1]

[0051] Outlier standard = Q1-4.5*IQR

[0052] In this case, when the IQR (e.g., 10 mV) is greater than or equal to a set voltage (e.g., 8 mV), the outlier criterion may be set to a result value calculated by applying 10 mV to the IQR of Equation 1, and when the IQR (e.g., 6 mV) is less than the set voltage (e.g., 8 mV), the outlier criterion may be set to a result value calculated by applying 6 mV to the IQR of Equation 1.

[0053] The processor 230 can detect abnormal cells in the battery idle state based on a set abnormal value standard. That is, the processor 230 can compare the voltage of each battery cell with the abnormal value standard and detect cells whose voltage is greater than the abnormal value standard as abnormal cells.

[0054] As described above, the processor 230 may set the outlier criteria for the entire interval to Q1-4.5*IQR and Q3+4.5*IQR, and use "Q1-4.5*IQR" corresponding to Median-Min for detecting Min.Cell having a high reduction rate when the battery is idle alone.

[0055] When IQR < 8 mV, processor 230 may set IQR = 8 mV for a small difference between battery cells and process Median-Min so that it is not detected when the battery cell voltage is within 40 mV. In the event that an abnormal cell is eventually detected, processor 230 may restrict high voltage connection and prohibit use of the battery.

[0056] Meanwhile, when the minimum rest time is not satisfied, the processor 230 may calculate the IQR based on the CCV and set an abnormal value standard for detecting an abnormal battery cell in the battery charging mode.

[0057] Specifically, when the time counted by the timer 220 does not exceed the minimum rest time (for example, two hours), as shown in FIG. Figure 3 As shown in , the processor 230 may obtain a median value of the voltage of the entire battery pack based on the CCV, and calculate an IQR based on the CCV based on the first quartile Q1 and the third quartile Q3.

[0058] In this case, the processor 230 may calculate the IQR based on the closed circuit voltage only when the battery state of charge (SOC) is greater than or equal to the set state of charge. The processor 230 may use the calculated IQR to set an abnormality standard for detecting an abnormal cell in the battery charging mode.

[0059] In other words, the abnormality criterion for detecting an abnormal cell in the battery charging mode may be set to the calculation result value of Equation 1, as with the abnormality criterion for detecting an abnormal cell in the battery idle state.

[0060] In this case, when the IQR is less than a set voltage (eg, 8 mV), the outlier criterion may be set to a result value calculated by applying the set voltage to the IQR of Equation 1.

[0061] The processor 230 can detect abnormal cells in the battery charging mode based on a set abnormal value standard. That is, the processor 230 can compare the voltage of each battery cell with the abnormal value standard and detect cells whose voltage is greater than the abnormal value standard as abnormal cells.

[0062] In the battery charging mode, the processor 230 may limit the SOC interval condition and detect abnormal cells only in the charging mode (plug-in charging) in the region where the SOC is 50% or higher. Figure 4 As shown in , in a section (3.6V to 3.75V section) in which no deviation occurs between cells depending on the SOC section, an abnormal value is detected even with a small deviation, so that detection of a normal value can be prevented based on the minimum condition of the deviation.

[0063] On the other hand, Figure 5 As shown in , it can be seen that in the region where the SOC is low, the difference between cells tends to become worse during discharge. Although outliers are clear in the interval where the difference between cells becomes worse, when the voltage difference between cells is small (such as Figure 4 Even small variations in the specific charging range (3.6V to 3.75V) can increase the probability of false detection (including normal cells). Therefore, it can be confirmed that in order to eliminate the probability of false detection, a conditional, rather than unconditional, statistical analysis is required.

[0064] That is, because the risk is low unless it is a high energy interval, e.g. Figure 5 The region with low SOC shown in can be excluded from abnormal cell diagnosis. On the other hand, since the SOC of 50% or more changes uniformly during charging, the deviation between cells in this section can be used to detect abnormal cells.

[0065] The processor 230 may include any one of a BMS, a battery pack control module (BPCM), a central processing control unit (CPU), an electronic control unit (ECU), and a microcontroller unit (MCU).

[0066] Figure 61 is a flowchart for describing an abnormal cell diagnosis method using cell voltage deviation according to an embodiment of the present invention. Specifically, Figure 6 A flowchart for describing an abnormal cell diagnosis method in a battery idle mode is shown.

[0067] The abnormal monomer diagnosis method described herein is merely one example of the present invention. Furthermore, the present invention is not limited to each of the operations and sequences described below, and various operations may be added as needed, and the operations below may be performed in a different order. This also applies to the other examples below.

[0068] refer to Figure 2 and Figure 6 , in operation 610 , the voltage measurement module 210 may measure an initial OCV of each battery cell.

[0069] Next, in operation 620 , the processor 230 may determine whether the time counted for each battery cell by the timer 220 satisfies a minimum rest time.

[0070] In this case, when the minimum rest time is met (2 hours < minimum rest time) ("Yes" in 620), in operation 630, the processor 230 can obtain the median value of the voltage of the entire battery pack based on the initial OCV, and calculate the IQR based on the first quartile Q1 (-25%) and the third quartile Q3 (25%), and the first quartile Q1 and the third quartile Q3 are determined based on the obtained median value.

[0071] In this case, when the calculated IQR is less than the set voltage (eg, 8 mV) (“Yes” in operation 640 ), the processor 230 may set the IQR to 8 mV in operation 650 .

[0072] Next, in operation 660 , the processor 230 may set an outlier criterion using IQR (Q1-4.5*IQR).

[0073] Next, in operation 670 , the processor 230 may compare the individual cell voltages to an outlier criterion.

[0074] In this case, when the abnormal value criterion is less than the single cell voltage ("Yes" in operation 670), the processor 230 may detect the corresponding cell as an abnormal cell in operation 680. On the other hand, when the abnormal value criterion is not less than the single cell voltage ("No" in operation 670), the processor 230 may determine that the corresponding cell is operating normally.

[0075] Meanwhile, when the minimum rest time is not satisfied ("No" in operation 620), the processor 230 may check whether the current mode is the charging mode in operation 690. When the current mode is checked and found to be the charging mode ("Yes" in operation 690), the processor 230 may execute Figure 7 On the other hand, when the current mode is checked and found not to be the charging mode (“No” in operation 690 ), the processor 230 may determine in operation 695 that the corresponding cell is operating normally.

[0076] Figure 7 1 is a flowchart for describing an abnormal cell diagnosis method using cell voltage deviation according to another embodiment of the present invention. Specifically, Figure 7 A method for diagnosing abnormal cells in a battery charging mode is shown. Figure 6 Flowchart of process A).

[0077] refer to Figure 2 and Figure 7 , in operation 710 , the voltage measurement module 210 may measure the CCV of each battery cell.

[0078] Next, in operation 720 , the processor 230 may check whether the battery state of charge (SOC) of each battery cell is greater than or equal to a set state of charge (eg, 50%).

[0079] In this case, when the SOC is greater than or equal to 50% ("Yes" in operation 720), in operation 730, the processor 230 can obtain the median value of the voltage of the entire battery pack based on the CCV, and calculate the IQR based on the first quartile Q1 (-25%) and the third quartile Q3 (25%), and the first quartile Q1 and the third quartile Q3 are determined based on the obtained median value.

[0080] In this case, when the calculated IQR is less than the set voltage (eg, 8 mV) (“Yes” in operation 740 ), the processor 230 may set the IQR to 8 mV in operation 750 .

[0081] Next, in operation 760 , the processor 230 may set an outlier criterion using IQR (Q1-4.5*IQR).

[0082] Next, in operation 770 , the processor 230 may compare the individual cell voltages to an outlier criterion.

[0083] In this case, when the abnormal value criterion is less than the single cell voltage ("Yes" in operation 770), the processor 230 may detect the corresponding cell as an abnormal cell in operation 780. On the other hand, when the abnormal value criterion is not less than the single cell voltage ("No" in operation 770), the processor 230 may determine whether charging is completed in operation 790.

[0084] Here, even when the SOC is not greater than or equal to 50% ("No" in operation 720), operation 790 may be performed. When it is determined that charging is completed ("Yes" in operation 790), this example may be terminated, but when charging is not completed ("No" in operation 790), the processor 230 may return to operation 710 and perform the process again.

[0085] According to the present invention, a method is used to obtain battery cell information according to the time point and situation in which the battery system is operated by comparing with the median value of all battery cell data and using the voltage difference between cells to thereby discover abnormal values, so that the efficiency of abnormal cell detection can be increased by applying conditions according to the charge state characteristics in each interval.

[0086] According to the present invention, while maintaining the existing diagnostic method of using absolute thresholds alone, a method of discovering outliers compared with the median value of battery cell data known as the interquartile range (IQR) is additionally applied to classify outliers based on the characteristics of the values ​​obtained at the same time point, so that the problem of false detection in the existing method can be solved.

[0087] However, effects that can be achieved by the present invention are not limited to the above-described effects, and other effects that are not described can be clearly understood by those skilled in the art from the detailed description.

[0088] Although the present invention has been described above with reference to the limited embodiments and drawings, the present invention is not limited thereto, and various modifications and changes are possible within the technical spirit of the present invention and within the scope of the described claims by those skilled in the art to which the present invention pertains.

Claims

1. An abnormal cell diagnosis device using cell voltage deviation, the abnormal cell diagnosis device comprising: a voltage measurement module configured to measure an initial open-circuit voltage or a closed-circuit voltage of each battery cell; a timer configured to count a minimum rest time of each battery cell; as well as A processor is configured to calculate an interquartile range based on the initial open-circuit voltage or the closed-circuit voltage depending on whether the minimum rest time is satisfied, set an outlier criterion, and detect an abnormal cell based on the set outlier criterion.

2. The abnormal unit diagnostic device according to claim 1, wherein: When the minimum rest time is satisfied, the processor calculates the interquartile range based on the initial open circuit voltage and sets the abnormal value standard for detecting the abnormal cell in a battery idle mode.

3. The abnormal unit diagnostic device according to claim 2, wherein: The processor obtains a median value of the voltage of the entire battery pack based on the initial open-circuit voltage, and calculates the interquartile range based on a first quartile (Q1) and a third quartile (Q3), wherein the first quartile (Q1) and the third quartile (Q3) are determined based on the obtained median value.

4. The abnormal unit diagnostic device according to claim 3, wherein: The outlier criterion is set to the value calculated by the following equation 1: [Equation 1] Outlier criterion = Q1-4.5*IQR, and Where Q1 is the first quartile and IQR is the interquartile range.

5. The abnormal unit diagnostic device according to claim 4, wherein: When the interquartile range is less than a set voltage, the outlier criterion is set to a result value calculated by applying the set voltage to the interquartile range of Equation 1.

6. The abnormal unit diagnostic device according to claim 1, wherein: When the minimum rest time is not satisfied, the processor calculates the interquartile range based on the closed-circuit voltage and sets the abnormal value standard for detecting the abnormal cell in a battery charging mode.

7. The abnormal unit diagnostic device according to claim 6, wherein: The processor obtains a median value of the voltage of the entire battery pack based on the closed-circuit voltage, and calculates the interquartile range based on a first quartile (Q1) and a third quartile (Q3), wherein the first quartile (Q1) and the third quartile (Q3) are determined based on the obtained median value.

8. The abnormal unit diagnostic device according to claim 7, wherein: The processor calculates the interquartile range only when the battery charge capacity is greater than or equal to a set charge capacity.

9. The abnormal unit diagnostic device according to claim 7, wherein: The outlier criterion is set to the value calculated by the following equation 1: [Equation 1] Outlier criterion = Q1-4.5*IQR, and Where Q1 is the first quartile and IQR is the interquartile range.

10. The abnormal unit diagnostic device according to claim 9, wherein: When the interquartile range is less than a set voltage, the outlier criterion is set to a result value calculated by applying the set voltage to the interquartile range of Equation 1.

11. A method for diagnosing abnormal cells using cell voltage deviation, the method comprising: The processor measures the initial open circuit voltage or closed circuit voltage of each battery cell through the voltage measurement module; The processor counts the minimum rest time of each battery cell through a timer; calculating, by the processor, an interquartile range based on the initial open circuit voltage or the closed circuit voltage depending on whether the minimum rest time is satisfied, and setting an outlier criterion; as well as The processor detects abnormal cells based on the set abnormal value standard.

12. The abnormal monomer diagnosis method according to claim 11, wherein: The setting of the outlier standard includes: When the minimum rest time is satisfied, calculating the interquartile range based on the initial open circuit voltage; and The calculated interquartile range is used to set the outlier criterion for detecting the abnormal cell in a battery idle mode.

13. The abnormal monomer diagnosis method according to claim 12, wherein: The calculation of the interquartile range based on the initial open circuit voltage includes: Obtaining a median value of the voltage of the entire battery pack based on the initial open circuit voltage; and The interquartile range is calculated based on a first quartile (Q1) and a third quartile (Q3), which are determined based on the obtained median value.

14. The abnormal monomer diagnosis method according to claim 13, wherein: The outlier criterion is set to the value calculated by the following equation 1: [Equation 1] Outlier criterion = Q1-4.5*IQR, and Where Q1 is the first quartile and IQR is the interquartile range.

15. The abnormal monomer diagnosis method according to claim 14, wherein: When the interquartile range is less than a set voltage, the outlier criterion is set to a result value calculated by applying the set voltage to the interquartile range of Equation 1.

16. The abnormal monomer diagnosis method according to claim 11, wherein: The setting of the outlier standard includes: When the minimum rest time is not satisfied, calculating the interquartile range based on the closed-circuit voltage; and The calculated interquartile range is used to set the outlier criterion for detecting the abnormal cell in a battery charging mode.

17. The abnormal monomer diagnosis method according to claim 16, wherein: The calculation of the interquartile range based on the closed-circuit voltage includes: obtaining a median value of the voltage of the entire battery pack based on the closed-circuit voltage; and The interquartile range is calculated based on a first quartile (Q1) and a third quartile (Q3), which are determined based on the obtained median value.

18. The abnormal monomer diagnosis method according to claim 17, wherein: The calculation of the interquartile range based on the closed-circuit voltage is performed only when the battery charge capacity is greater than or equal to a set charge capacity.

19. The abnormal monomer diagnosis method according to claim 17, wherein: The outlier criterion is set to the value calculated by the following equation 1: [Equation 1] Outlier criterion = Q1-4.5*IQR, and Where Q1 is the first quartile and IQR is the interquartile range.

20. The abnormal monomer diagnosis method according to claim 19, wherein: When the interquartile range is less than a set voltage, the outlier criterion is set to a result value calculated by applying the set voltage to the interquartile range of Equation 1.

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