Overheat diagnosis method, overheat diagnosis device providing same, and battery system

Abstract

The present disclosure relates to an overheat diagnosis method, an overheat diagnosis apparatus providing the same, and a battery system. The overheating diagnosis apparatus of the present invention includes: a measurement unit configured to measure a temperature of an object; a storage unit configured to store the temperature value measured by the measurement unit; and a control unit configured to: extract, at each diagnosis point at which the object is diagnosed to be overheated, a plurality of previous diagnosis points corresponding to a predetermined number of samples based on the diagnosis point; calculating a moving average value which is an average of the plurality of temperature values corresponding to each of the plurality of diagnosis points; calculating a standard deviation average value which is an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points; calculating an overheat reference value by adding an error value to the moving average value when the error value calculated by multiplying the standard deviation average value by a predetermined multiple is greater than or equal to a predetermined error reference value; and diagnosing the occurrence of an overheating event of the object by comparing the temperature value measured at each diagnosis point with the overheating reference value calculated at each diagnosis point.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0185631 filed on December 27, 2022 and Korean Patent Application No. 10-2023-0185646 filed on December 19, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a method of diagnosing overheating of an object (eg, a battery, etc.), and an overheating diagnosis device and a battery system providing the method. Background Art

[0004] Recently, as the demand for portable electronic products such as laptops, video cameras, and portable phones has increased dramatically, and as the development of electric vehicles, energy storage batteries, robots, satellites, etc. has officially started, research on high-performance batteries that can be repeatedly charged and discharged is being actively conducted.

[0005] Currently commercialized batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium batteries, etc. Among these batteries, lithium batteries have attracted much attention because they have almost no memory effect compared to nickel-based batteries, and they are freely charged and discharged, have a very low self-discharge rate, and have the advantages of high energy density.

[0006] Meanwhile, the temperature of the battery is a factor that significantly affects the performance of the battery. Generally, when the temperature distribution of the battery is at an appropriate temperature, the battery can operate efficiently. For example, when the temperature of the battery is too high, the safety of the cathode lattice of the battery is reduced, which may lead to performance degradation of the battery or accidents such as explosion. Therefore, it is necessary to accurately monitor the temperature of the battery.

[0007] Conventionally, overheating of a battery is diagnosed by comparing the measured temperature of the battery with a preset reference value. In the conventional method, the time interval between when an overheating event is diagnosed and when the battery explodes or the like is too short, making it difficult to take appropriate measures. In addition, the conventional method has the problem of misdiagnosing a temperature increase due to battery aging as an overheating event. Summary of the invention

[0008] [Technical issues]

[0009] The present disclosure relates to an overheat diagnosis method capable of diagnosing abnormal heating behavior (hereinafter referred to as overheating) of an object with high accuracy, and an overheat diagnosis device and a battery system providing the method.

[0010] [Technical solution]

[0011] According to one aspect of the present disclosure, an overheat diagnosis device includes: a measuring unit configured to measure a temperature of an object; a storage unit configured to store a temperature value measured by the measuring unit; and a control unit configured to: at each diagnosis point for diagnosing overheat of the object, extract a plurality of previous diagnosis points corresponding to a predetermined number of samples based on the diagnosis point; calculate a moving average value as an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; calculate a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points; calculate an overheat reference value by adding the error value to the moving average value when an error value calculated by multiplying the standard deviation average value by a predetermined multiple is greater than or equal to a predetermined error reference value; and diagnose the occurrence of an overheat event of the object by comparing the temperature value measured at each diagnosis point with the overheat reference value calculated at each diagnosis point.

[0012] The control unit may correct the plurality of temperature values ​​according to a result of comparing each of the plurality of temperature values ​​corresponding to the plurality of diagnosis points with the moving average value when the error value is less than the error reference value, and calculate the overheat reference value based on the plurality of corrected temperature values.

[0013] The control unit may correct the temperature value for each of the plurality of temperature values ​​by adding a predetermined correction value to the temperature value when the temperature value is greater than a moving average value, and by subtracting the correction value from the temperature value when the temperature value is less than the moving average value.

[0014] The control unit may diagnose that an overheating event has occurred in the object when the measured temperature value exceeds an overheating reference value.

[0015] According to another aspect of the present disclosure, a battery system includes: a battery including a plurality of battery cells; a measuring unit configured to measure a temperature of the battery; a storage unit configured to store a temperature value measured by the measuring unit; and a control unit configured to: at each diagnostic point for diagnosing overheating of the battery, extract a plurality of previous diagnostic points corresponding to a predetermined number of samples based on the diagnostic point; calculate a moving average value as an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnostic points; calculate a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnostic points; calculate an overheat reference value by adding the error value to the moving average value when an error value calculated by multiplying the standard deviation average value by a predetermined multiple is greater than or equal to a predetermined error reference value; and diagnose the occurrence of an overheat event of the battery by comparing the temperature value measured at each diagnostic point with the overheat reference value calculated at each diagnostic point.

[0016] The control unit may correct the plurality of temperature values ​​according to a result of comparing each of the plurality of temperature values ​​corresponding to the plurality of diagnosis points with the moving average value when the error value is less than the error reference value, and calculate the overheat reference value based on the plurality of corrected temperature values.

[0017] The control unit may correct the temperature value for each of the plurality of temperature values ​​by adding a predetermined correction value to the temperature value when the temperature value is greater than a moving average value, and by subtracting the predetermined correction value from the temperature value when the temperature value is less than the moving average value.

[0018] The control unit may diagnose that an overheat event has occurred in the battery when the measured temperature value exceeds an overheat reference value.

[0019] According to another aspect of the present disclosure, an overheating diagnosis method includes: a temperature data collection step of receiving a temperature value as a temperature measurement value of a battery from a measurement unit at a predetermined diagnosis point for diagnosing overheating of the battery, the battery including a plurality of battery cells; a sample group determination step of extracting a plurality of previous diagnosis points corresponding to the number of samples based on the diagnosis point; an overheating reference value calculation step, including: a step of calculating a moving average value as an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; a step of calculating a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points, and calculating an error value by multiplying the standard deviation average value by a predetermined multiple; and a step of calculating an overheating reference value by adding the error value to the moving average value when the calculated error value is greater than or equal to a predetermined error reference value; and an overheating diagnosis step of diagnosing the occurrence of an overheating event of the battery by comparing the temperature value with the overheating reference value.

[0020] The overheat reference value calculation step may further include, when the error value is less than the error reference value: a temperature value correction step, correcting the multiple temperature values ​​according to the result of comparing each of the multiple temperature values ​​corresponding to the multiple diagnostic points with the moving average value, and in the overheat reference value calculation step, the overheat reference value may be calculated based on the multiple corrected temperature values.

[0021] The temperature value correction step may include: a step of extracting a plurality of temperature values ​​corresponding to each of a plurality of diagnostic points; a step of comparing each of the plurality of temperature values ​​with a moving average; a first correction step of correcting the temperature value by adding a predetermined correction value to the temperature value when the temperature value is greater than or equal to the moving average as a result of the comparison; and a second correction step of correcting the temperature value by subtracting the predetermined correction value from the temperature value when the temperature value is less than the moving average.

[0022] The overheat diagnosis step may include: a step of comparing the measured temperature value with an overheat reference value; a first diagnosis step of diagnosing that an overheat event has occurred in the battery when the measured temperature value exceeds the overheat reference value as a result of the comparison; and a second diagnosis step of diagnosing the battery as a normal state in which no overheat event has occurred when the measured temperature value is less than or equal to the overheat reference value as a result of the comparison.

[0023] [Beneficial Effects]

[0024] Unlike conventional diagnostic methods that use fixed reference values, according to the present disclosure, by calculating an overheat reference value that reflects the temperature trend of an object at each overheat diagnostic point, and comparing the calculated overheat reference value with the measured temperature to perform overheat diagnosis, it is possible to determine with high accuracy whether an overheat event has occurred.

[0025] According to the present disclosure, by calculating the overheat reference value based on the moving average and standard deviation at each diagnosis point, the problem of misdiagnosing a temperature rise due to aging of an object (eg, a battery, etc.) as an overheat event can be prevented.

[0026] According to the present disclosure, when the interval between the overheat reference value and the moving average value is significantly narrow, the accuracy of diagnosis can be significantly improved by correcting a plurality of temperature values ​​that are a basis for calculating the overheat reference value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a block diagram describing an overheat diagnosis apparatus according to an embodiment.

[0028] Figure 2 is a block diagram illustrating a battery system according to another embodiment.

[0029] Figure 3 is a flowchart describing an overheat diagnosis method according to an embodiment.

[0030] Figure 4 is a detailed description Figure 3 Flow chart of the superheat reference value determining step (S300).

[0031] Figure 5 is a detailed description Figure 4 Flow chart of the temperature value correction step (S370).

[0032] Figure 6 is an example diagram showing temperature changes of a non-defective battery in a charging mode.

[0033] Figure 7 is an example diagram showing temperature changes of a defective battery in a charging mode. DETAILED DESCRIPTION

[0034] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar parts are given the same, similar figure marks, and will not be described repeatedly. The suffixes "module" and / or "unit" of the parts used in the following description are given or mixed only in consideration of the ease of writing the specification, and therefore, they themselves do not have different meanings or functions from each other. In addition, when it is determined that the detailed description of the known technology related to the present disclosure may blur the main points of the present disclosure, the detailed description will be omitted. In addition, it should be understood that the accompanying drawings are provided only to enable easy understanding of the exemplary embodiments of the present disclosure, and the spirit of the present disclosure is not limited by the accompanying drawings, but includes all modifications, equivalents and substitutions included in the spirit and scope of the present disclosure.

[0035] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited to these terms. The above terms are used only for the purpose of distinguishing one component from another.

[0036] It should be understood that when a component is referred to as being “connected to” or “coupled to” another component, it may be directly connected or coupled to the other component, or connected to the other component with another component interposed therebetween. On the other hand, it should be understood that when an element is referred to as being “directly connected to” or “directly coupled to” another element, it may be connected or coupled to the other element without another element interposed therebetween.

[0037] It will be further understood that the terms “including” or “having” used in this specification explicitly indicate the existence of the features, numbers, steps, operations, components, parts or a combination thereof mentioned in this specification, but do not exclude the existence or addition of one or more other features, numbers, steps, operations, components, parts or a combination thereof.

[0038] Figure 1 is a block diagram describing an overheat diagnosis apparatus according to an embodiment.

[0039] Reference Figure 1 The overheat diagnosis device 1 includes a measuring unit 11 , a storage unit 13 and a control unit 15 .

[0040] The measuring unit 11 may measure the temperature of the object at each point (hereinafter referred to as a diagnosis point) where the object is diagnosed to be overheated, and send the measurement result to the control unit 15. For example, the measuring unit 11 may include a temperature sensor that measures the temperature of the object. In this case, the object may include, but is not limited to, a battery, and may include various devices that need to be predicted in advance before an overheating event occurs.

[0041] The storage unit 13 may store the temperature value of the object measured by the measuring unit 11 at each diagnostic point. In addition, the storage unit 13 may store the moving average value MA, the standard deviation SD, the standard deviation average value SD_ave, and the overheat reference value Th calculated by the control unit 15 at each diagnostic point. For example, the temperature value T of the object corresponding to a certain diagnostic point, the moving average value MA, the standard deviation SD, the standard deviation average value SD_ave, and the overheat reference value Th may be stored in the storage unit 13 in the form of a lookup table.

[0042] When the diagnostic point according to the preset condition is reached, the control unit 15 calculates the moving average MA and the overheat reference value Th having a predetermined value greater than the moving average. For example, when the object is a battery, the diagnostic point may be a point when charging of the battery starts or a point when discharging of the battery ends. However, the diagnostic point is not limited thereto, and various settings may be made.

[0043] First, the control unit 15 may extract a plurality of diagnostic points included in a preset sample number SN to determine a sample group, while counting diagnostic points in the direction of the previous diagnostic point based on the current diagnostic point N. In this case, the sample number SN is the number of the plurality of diagnostic points included in the sample group, and may be determined as an optimal number based on experiments or the like.

[0044] The sample group is a subgroup of a plurality of past diagnosis points as a whole, and may be a group used for calculating a moving average MA and a standard deviation average SD_ave, etc., which will be described below.

[0045] (Table 1)

[0046]

[0047] Table 1 above shows an example of a lookup table of a temperature value T, a moving average MA, a standard deviation SD, a standard deviation average SD_ave, an error value ER, an overheat reference value Th, etc., about an object corresponding to each of a plurality of diagnosis points. Hereinafter, calculation of the overheat reference value Th required for overheat diagnosis at the Nth diagnosis point will be described in detail. N In addition, the sample number SN is assumed to be 5. However, the sample number SN is not limited thereto and may be determined as various positive integers.

[0048] For reference, at the first diagnostic point 1 in Table 1, there is no previous diagnostic point to constitute the sample group, so the moving average MA, the standard deviation SD, the standard deviation average SD_ave, and the overheat reference value Th may be difficult to calculate directly (therefore, the corresponding values ​​in Table 1 are represented as empty). In addition, since the number of previous diagnostic points for constituting the sample group is insufficient at the predetermined diagnostic points adjacent to the first diagnostic point 1 (e.g., 2, 3, 4, and 5), it may be difficult to calculate the moving average MA, the standard deviation SD, the standard deviation average SD_ave, and the overheat reference value Th. In this case, the designer may provide the moving average MA, the standard deviation SD, the standard deviation average SD_ave, and the overheat reference value Th at the initial diagnostic point and the adjacent diagnostic points (e.g., 1, 2, 3, 4, and 5) with values ​​calculated according to experimental averaging.

[0049] While counting the diagnostic points in the previous direction based on the Nth diagnostic point N as the current diagnostic point, the control unit 15 can extract the N-1th diagnostic point, the N-2nd diagnostic point, the N-3rd diagnostic point, the N-4th diagnostic point and the N-5th diagnostic point corresponding to 5 as the sample number SN to determine the sample group.

[0050] The control unit 15 may extract a plurality of diagnosis points N-1, N-2, N-3, N-4, and N-5 to determine a sample group, and calculate an overheat reference value Th for overheat diagnosis based on a temperature value measured at each of the plurality of diagnosis points N-1, N-2, N-3, N-4, and N-5 belonging to the sample group. N .

[0051] For example, when the object is a battery, if the battery is used for a long period of time, the internal resistance value increases due to aging, and the temperature may gradually increase with the increase in the internal resistance value. N When diagnosing battery overheating, it can prevent the problem of misdiagnosing a temperature rise due to long-term use as an overheating event. In addition, it can solve the problem of misdiagnosing a temporary temperature rise as an overheating event.

[0052] Next, the control unit 15 calculates an overheat reference value Th corresponding to the Nth diagnosis point based on the temperature value T measured at each of the plurality of diagnosis points N-1, N-2, N-3, N-4, and N-5 belonging to the sample group. N .

[0053] According to an embodiment, the control unit 15 converts the temperature value T measured at the Nth diagnosis point into N and the overheat reference value Th calculated at the Nth diagnostic point NFor example, referring to Table 1, the moving average MA N and standard deviation of the mean value SD N _ave is the calculated superheat reference value Th N Required value. Standard deviation SD N is not the value required when diagnosing an overheat condition at the Nth diagnostic point, but is the value required for determining an overheat event at subsequent diagnostic points N+1, N+2, ..., and therefore, the standard deviation SD N It can be calculated from the Nth diagnosis point and stored in the storage unit 13.

[0054] In the following, referring to Table 1, the moving average MA calculated by the control unit 15 at the Nth diagnosis point will be described. N , standard deviation SD N , standard deviation mean SD N _ave, error value ER N and overheat reference value Th N .

[0055] The control unit 15 may average the multiple temperature values ​​29.4°C, 29.3°C, 29.4°C, 29.3°C and 29.5°C corresponding to each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group (29.4°C + 29.3°C + 29.4°C + 29.3°C + 29.5°C / 5 = 29.38°C) to calculate the moving average value MA corresponding to the Nth diagnostic point N N (29.38°C). That is, the moving average MA at the Nth diagnostic point N It can be calculated by the following formula 1.

[0056]

[0057] Referring to Table 1 above and Table 2 below, the control unit 15 may calculate the moving average value MA corresponding to the Nth diagnostic point N based on the temperature value T corresponding to each of the plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group and the moving average value MA corresponding to the Nth diagnostic point N. N To calculate the standard deviation SD corresponding to the Nth diagnostic point N .

[0058] (Table 2)

[0059]

[0060] As mentioned above, the standard deviation SD corresponding to the Nth diagnostic point NIt is not a value necessary for diagnosing an overheating condition at the Nth diagnostic point, but a value necessary for diagnosing whether an overheating event of an object has occurred at subsequent diagnostic points N+1, N+2, ... Therefore, at the Nth diagnostic point, the standard deviation SD corresponding to the Nth diagnostic point can be calculated. N And the standard deviation SD N Stored in the storage unit 13.

[0061] (Table 3)

[0062]

[0063] Referring to Tables 1 and 3 above, the control unit 15 may calculate the standard deviations SD corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group based on the plurality of standard deviations SD corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group. N-5 , SD N-4 , SD N-3 , SD N-2 and SD N-1 To calculate the standard deviation mean SD corresponding to the Nth diagnostic point N _ave(0.0742).

[0064] The control unit 15 can calculate the overheat reference value Th N , the overheat reference value Th N is the moving average MA N First, the control unit 15 can calculate the standard deviation average value SD according to the following formula 2 N _ave is multiplied by the preset multiple α to calculate the error value ER N In this case, the multiple α is a value for reflecting various errors, and can be determined to be various values ​​through experiments. Hereinafter, the multiple α is assumed to be a natural number 3 (α=3).

[0065] ER N =SD N _ave×α-Formula (2)

[0066] For example, referring to Table 3 and Formula 2, the control unit 15 can calculate the standard deviation average value SD N _ave(0.07442) is multiplied by the multiple α,3 to calculate the error value ER N ,0.22326.

[0067] Error value ER N It is a value that reflects the error that may occur in various situations such as temperature measurement. N When it is very small, the moving average MA N and overheat reference value Th NThat is, even if no actual overheating event occurs, an erroneous diagnosis may occur: according to the temperature value T measured at the Nth diagnostic point, N Exceeds the overheat reference value Th calculated at the Nth diagnostic point N In other words, when the arithmetic calculation of the overheating reference value Th is used to calculate N When the basic error value ER is smaller than the normally expected value, there is a high possibility of misdiagnosis.

[0068] According to an embodiment, when the error value ER N Greater than or equal to the predetermined error reference value TH N _ER, the control unit 15 can N With Moving Average MA N Add to calculate the superheat reference value Th N In the following, the error reference value TH N _ER is assumed to be the same as the moving average MA N The value corresponding to 1% of (29.38°C x 0.1 = 0.2938), but is not limited thereto and may be determined as various values.

[0069] According to another embodiment, when the error value ER N Less than the error reference value TH N _ER, the control unit 15 corrects the temperature value T corresponding to each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group. That is, the control unit 15 can correct the temperature data corresponding to each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group.

[0070] According to another embodiment, when the temperature value T corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2 and N-1 is greater than or equal to the moving average value MA N When the temperature value T corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2 and N-1 is less than the moving average MA N When , the temperature value may be corrected by subtracting the correction value β from the temperature value T. Hereinafter, the correction value β is assumed to be 2, but is not limited thereto and may be determined as various values.

[0071] Referring to the above formula 3, the error value ER N (0.22326) is less than the reference value TH NThe control unit 15 can correct the multiple temperature values ​​29.4°C, 29.3°C, 29.4°C, 29.3°C and 29.5°C belonging to the sample group by calculating ±correction value β=2 for each of the multiple temperature values ​​29.4°C, 29.3°C, 29.4°C, 29.3°C and 29.5°C corresponding to the multiple diagnosis points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group.

[0072] According to formula 1, the moving average MA N is 29.38°C. Specifically, since the temperature value T at the N-5th diagnosis point N-5 (29.4℃) is greater than or equal to the moving average MA N (29.38°C), so the control unit 15 can calculate the temperature value T at the N-5th diagnosis point by adding the correction value β=2 to the temperature value T at the N-5th diagnosis point. N-5 (29.4°C) is added to calculate the temperature value T at the processed Nth diagnosis point N-5 29.4+2=31.4℃. Since the temperature value T at the N-4th diagnosis point N-4 (29.3℃) is less than the moving average MA N 29.38°C, so the control unit 15 can calculate the temperature T at the N-4 diagnosis point by N-4 (29.3°C) minus the correction value β=2 to calculate the temperature value T at the processed N-4th diagnosis point N-1 (29.3-2=27.3℃). When the temperature values ​​29.4℃, 29.3℃ and 29.5℃ of the N-3rd, N-2nd and N-1st diagnostic points (N-3, N-2 and N-1) are corrected respectively by the same method, the corrected temperature value T' for each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 can be 31.4℃, 27.3℃, 31.4℃, 27.3℃ and 31.5℃.

[0073] When the temperature value at each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 is corrected, the control unit 15 can calculate the moving average value MA again based on Formula 1, Formula 2, etc. based on the corrected temperature value T'31.4°C, 27.3°C, 31.4°C, 27.3°C and 31.5°C at each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1. N ', standard mean deviation SD N _ave' and error value ER N '.

[0074] Next, the control unit 15 can convert the error value ER intoN With Moving Average MA N Add to calculate the superheat reference value Th N .

[0075] Th N =MA N +ER N – Formula (3)

[0076] For example, when the temperature value T at each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 is corrected, the control unit 15 may calculate the moving average value MA based on the moving average value MA. N ' and error value ER N 'To calculate the superheat reference value Th N , the moving average MA N ' and error value ER N ' is calculated based on the corrected temperature value T' at each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1. For example, the overheat reference value Th calculated based on the corrected temperature value T' at each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 N Assume 32.5℃.

[0077] Next, the control unit 15 can convert the temperature value T measured at the Nth diagnosis point into N and the overheat reference value Th calculated at the Nth diagnostic point N The comparison is performed to diagnose whether an overheating event has occurred in the object.

[0078] For example, referring to Table 1, the temperature value T measured at the Nth diagnostic point is N Assume it is 30℃. Since the temperature value T corresponding to the Nth diagnosis point N (30℃) is less than the overheat reference value Th corresponding to the Nth diagnosis point N (32.5°C), so the control unit 35 can diagnose that no overheating event has occurred. That is, the control unit 35 can diagnose that the temperature of the object is in a normal state.

[0079] Figure 2 is a block diagram illustrating a battery system according to another embodiment.

[0080] Reference Figure 2 , the battery system 2 includes a battery 10 , a relay 20 and a battery management system (BMS) 30 .

[0081] The battery 10 may include a plurality of battery cells connected in series and / or in parallel. Figure 2, three battery cells connected in parallel are shown, but the present disclosure is not limited thereto, and the battery 10 may include various numbers of battery cells connected in series and / or in parallel. In some embodiments, the battery cells may be rechargeable secondary batteries. In addition,

[0082] For example, in the battery 10, a predetermined number of battery cells are connected in parallel to form a battery bank, and a predetermined number of battery banks are connected in series to form a battery pack, so that the desired power can be supplied to an external device. As another example, in the battery 10, a predetermined number of battery cells are connected in parallel to form a battery bank, and a predetermined number of battery banks are connected in parallel to form a battery pack, so that the desired power can be supplied to an external device. However, the present disclosure is not limited to such a connection, and the battery 10 includes a plurality of battery banks including a plurality of battery cells connected in series and / or in parallel, and the plurality of battery banks may also be connected in series and / or in parallel.

[0083] exist Figure 2 In the embodiment, the battery 10 is connected between two output terminals OUT1 and OUT2 of the battery system 2. In addition, the relay 20 is connected between the positive electrode of the battery system 2 and the first output terminal OUT1. Figure 2 The illustrated configurations and connection relationships between these configurations are examples, and the present disclosure is not limited thereto.

[0084] The relay 20 controls the electrical connection between the battery system 2 and the external device. When the relay 20 is turned on, the battery system 2 and the external device are electrically connected for charging or discharging. When the relay 20 is turned off, the battery system 2 is electrically separated from the external device. In this case, the external device may be a charger in a charging cycle in which the battery 10 is charged by supplying power to the battery 10, and may be a load in a discharging cycle in which the battery 10 is discharged to the external device.

[0085] The BMS 30 includes a measuring unit 31 , a storage unit 33 , and a control unit 35 . Figure 1 The overheating diagnostic device 1 shown may correspond to Figure 2 Detailed description, the functions respectively performed by the measuring unit 11, the storage unit 13 and the control unit 15 of the overheat diagnosis device 1 may correspond to the functions respectively performed by the measuring unit 31, the storage unit 33 and the control unit 35 of the BMS 30. For example, the overheat diagnosis device 1 may be configured separately from the battery system 2. As another example, in the case of Figure 2 In the battery system 2 shown, the BMS 30 may perform the function of the overheat diagnosis device 1 .

[0086] Hereinafter, descriptions of the functions of each of the measuring unit 31 , the storage unit 33 , and the control unit 35 of the BMS 30 will be replaced with descriptions of the functions of the measuring unit 11 , the storage unit 13 , and the control unit 15 of the overheat diagnostic device 1 , respectively.

[0087] Figure 3 is a flowchart describing an overheat diagnosis method according to an embodiment. Figure 4 is a detailed description Figure 3 Flow chart of the superheat reference value determining step (S300). Figure 5 is a detailed description Figure 4 Flow chart of the temperature value correction step (S370).

[0088] In the following, reference is made to Figures 1 to 5 , an overheat diagnosis method and an overheat diagnosis device 1 and a battery system 2 providing the method will be described. Hereinafter, a measurement unit 31, a storage unit 33, and a control unit 35 of a BMS 30 will be described, which will be identically applied to the measurement unit 11, the storage unit 13, and the control unit 15 of the overheat diagnosis device 1. In addition, although the battery 10 is described, the present disclosure is not limited thereto and may be identically applied to various objects requiring temperature measurement.

[0089] First, the control unit 35 receives temperature data including information on the measured temperature of the battery 10 from the measurement unit 31 at a predetermined diagnosis point for diagnosing overheating of the battery 10 ( S100 ).

[0090] When a diagnosis point according to a preset condition is reached, the measuring unit 31 may measure the temperature of the battery 10, and send the measurement result to the control unit 35. For example, the measuring unit 31 may include a temperature sensor to measure the temperature of the battery 10 at each diagnosis point, and send the measurement result to the control unit 35. As another example, the measuring unit 31 may receive a temperature value as a result of the temperature sensor measuring the temperature of the battery 10 at predetermined time intervals or in real time, extract temperature data corresponding to the predetermined diagnosis point, and send the extracted temperature data to the control unit 35.

[0091] Next, the control unit 35 extracts a plurality of previous diagnosis points corresponding to the sample number SN based on the current diagnosis point N to determine a sample group (S200).

[0092] Referring to Table 1, while taking into account the diagnostic points in the direction of the previous diagnostic point based on the current diagnostic point N, the control unit 35 can extract the N-5th diagnostic point, the N-4th diagnostic point, the N-3rd diagnostic point, the N-2nd diagnostic point and the N-1th diagnostic point corresponding to 5 as the sample number SN to determine the sample group.

[0093] The control unit 35 may extract a plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 to determine a sample group, and based on the temperature value T measured at each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group. N-5 , T N-4 , T N-3 , T N-2 and T N-1 To calculate the overheat reference value Th for diagnosis N The superheat reference value Th is calculated by using the following method N , can prevent the problem of misdiagnosing temperature rises due to battery aging as overheating events. In addition, it can solve the problem of misdiagnosing temporary temperature rises due to various reasons as overheating events.

[0094] Next, the control unit 35 determines the temperature based on the temperature value T measured at each of the plurality of diagnosis points N-5, N-2, N-3, N-4, and N-1 belonging to the sample group. N-5 , T N-4 , T N-3 , T N-2 and T N-1 To calculate the overheat reference value Th corresponding to the Nth diagnostic point N (S300).

[0095] In step S300, refer to Figure 4 The control unit 35 calculates a moving average MA corresponding to the Nth diagnostic point by averaging a plurality of temperature values ​​corresponding to each of a plurality of diagnostic points belonging to the sample group. N (S310).

[0096] Specifically, referring to Table 1, the control unit 35 may average a plurality of temperature values ​​29.4°C, 29.3°C, 29.4°C, 29.3°C, and 29.5°C corresponding to each of a plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group (29.4°C + 29.3°C + 29.4°C + 29.3°C + 29.5°C / 5 = 29.38°C) to calculate a moving average value MA corresponding to the Nth diagnostic point. N (29.38℃).

[0097] In step S300, the control unit 35 calculates a standard deviation average value SD by averaging a plurality of standard deviations corresponding to each of a plurality of diagnostic points belonging to the sample group. N _ave, and based on the standard deviation mean SD N _ave to calculate the error value ER N (S330).

[0098] Specifically, referring to Table 3, the control unit 35 may calculate the standard deviation SD corresponding to each of the plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group based on the plurality of standard deviations SD corresponding to each of the plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1. N-5 , SD N-4 , SD N-3 , SD N-2 and SD N-1 , to calculate the standard deviation mean SD corresponding to the Nth diagnostic point N _ave(0.07442).

[0099] The control unit 35 can calculate the standard deviation average value SD according to the above formula 2 N _ave is multiplied by the preset multiple α to calculate the error value ER N In this case, the multiple α can be determined to be various values ​​through experiments. In the following, the multiple α is assumed to be a natural number 3 (α=3). For example, referring to Table 3 and Formula 2, the control unit 35 can calculate the standard deviation average value SD by N _ave(0.07442) is multiplied by the multiple α,3 to calculate the error value ER N ,0.22326.

[0100] In step S300, the control unit 35 sets the error value ER N and the predetermined error reference value TH N _ER is compared (S350).

[0101] Error value ER N It is a value that reflects the error that may occur in various situations such as temperature measurement. N When it is very small, the moving average MA N The interval between the temperature value T and the overheat reference value Th may be very narrow. That is, even if no actual overheat event occurs, the following erroneous diagnosis may occur: according to the temperature value T measured at the Nth diagnosis point N Exceeds the overheat reference value Th calculated at the Nth diagnostic point N In other words, when the error value ER, which is the basis for calculating the overheat reference value Th, is smaller than a normally expected value, there is a high possibility of erroneous diagnosis.

[0102] In step S300, when the error value ER N Less than the error reference value TH N _ER, the control unit 35 corrects the temperature value T corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group (S370).

[0103] For example, the error reference value TH N _ER can be calculated as the moving average MA N The value corresponding to 1% of (29.38°C x 0.1 = 0.2938), but is not limited thereto and may be determined as various values.

[0104] In step S370, refer to Figure 4 , the control unit 15 extracts a plurality of temperature values ​​corresponding to each of a plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group (S371).

[0105] In step S370, the control unit 15 compares each of the plurality of temperature values ​​with the moving average MA. N Perform comparison (S373).

[0106] For example, for each of the plurality of temperature values, the control unit 15 may determine whether the temperature value is greater than or equal to the moving average MA N .

[0107] In step S370, as a result of the comparison, when the temperature value is greater than or equal to the moving average MA N When (S372, YES), the control unit 15 corrects the temperature value by adding a predetermined correction value β to the temperature value (S373).

[0108] In step S370, as a result of the comparison, when the temperature value is less than the moving average MA N When (S372, No), the control unit 15 corrects the temperature value by subtracting a predetermined correction value β from the temperature value (S374).

[0109] For example, referring to Table 1 above, the correction value β=2 can be obtained by comparing the correction value β=2 with the moving average MA among the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group. N The temperature value T is corrected by adding each of the temperature values ​​29.4°C, 29.4°C and 29.5°C at the N-5th diagnostic point, the N-3rd diagnostic point and the N-1th diagnostic point corresponding to the value (29.38°C) or more. In addition, the temperature value T can be corrected by adding each of the temperature values ​​29.4°C, 29.4°C and 29.5°C at the N-5th diagnostic point, the N-3rd diagnostic point and the N-1th diagnostic point corresponding to the value less than the moving average MA from the plurality of diagnostic points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group. NThe temperature value T is corrected by subtracting the correction value β=2 from each of the temperature values ​​29.3°C and 29.3°C at the N-4th diagnostic point and the N-2nd diagnostic point (29.38°C). Then, the temperature values ​​29.4°C, 29.3°C, 29.4°C, 29.3°C and 29.5°C at each of the multiple diagnostic points N-5, N-4, N-3, N-2 and N-1 can be corrected to 31.4°C, 27.3°C, 31.4°C, 27.3°C and 31.5°C.

[0110] Reference Figure 4 and Figure 5 , the control unit 15 can perform steps S310 and S330 again according to the corrected temperature values ​​T'31.4°C, 27.3°C, 31.4°C, 27.3°C and 31.5°C at the multiple diagnosis points N-5, N-4, N-3, N-2 and N-1 to calculate the corrected moving average MA again. N ' and the corrected error value ER N As a result of the determination in step S350, when the corrected error value ER N 'Greater than the corrected error reference value TH N _ER' (S350, yes), the following step S390 may be executed. That is, steps S370, S310 and S330 may be repeated until the determination result of step S350 is yes. In this case, the corrected error reference value TH N _ER' can be calculated as the corrected moving average MA N ' corresponds to a value of 1%.

[0111] In step S370, the determination control unit 15 corrects all of the temperature values ​​corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2 and N-1 belonging to the sample group (S375).

[0112] In step S370, when there is an uncorrected temperature value among the plurality of temperature values ​​as a result of the determination (S375, No), the control unit 15 repeats from step S372.

[0113] In step S370, when the correction is completed for all the temperature values ​​among the plurality of temperature values ​​belonging to the sample group as a result of the determination (S375, Yes), the control unit 15 may store in the storage unit 32 a plurality of corrected temperature values ​​T corresponding to each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 belonging to the sample group. N-5 '、T N-4 '、T N-3 '、T N-2 ' and T N-1', and the correction is completed (S376).

[0114] According to an embodiment, at the Nth diagnostic point, even if the temperature value is corrected according to step S370, measurement is performed at each of the plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1, and thus the plurality of temperature values ​​29.4° C., 29.3° C., 29.4° C., 29.3° C., and 29.5° C. already stored in the storage unit 32 may not be corrected. That is, at the Nth diagnostic point, even if the temperature value is corrected according to step S370, the temperature value may be corrected based on the corrected moving average MA. N ' and the corrected error value ER N 'Calculate the corrected superheat reference value Th N .

[0115] According to another embodiment, at the Nth diagnostic point, even if the temperature value is corrected according to step S370, the temperature value is measured at each of the plurality of diagnostic points N-5, N-4, N-3, N-2, and N-1, and thus the plurality of temperature values ​​29.4° C., 29.3° C., 29.4° C., 29.3° C., and 29.5° C. already stored in the storage unit 32 may be changed to the plurality of corrected temperature values ​​31.4° C., 27.3° C., 31.4° C., 27.3° C., and 31.5° C. Therefore, when calculating the moving average MA at the N+1 diagnostic point, the N+2 diagnostic point, and so on N+1 、MA N+2 Equal and corrected error value ER N+1 +ER N+2 At the same time, they can be calculated based on a plurality of temperature values ​​corrected at the Nth diagnosis point.

[0116] In step S300, return to reference Figure 4 , the control unit 15 calculates the error value ER N or ER N 'With moving average MA N or MA N 'Add to calculate the superheat reference value Th N or N '(S390).

[0117] For example, when the temperature value T of each of the plurality of diagnosis points N-5, N-4, N-3, N-2, and N-1 is corrected, the control unit 15 can calculate the corrected error value ER by calculating the temperature value T′ of each of the plurality of corrected diagnosis points N-5, N-4, N-3, N-2, and N-1. N ' and the calculated adjusted moving average MA N 'Add to calculate the corrected superheat reference value Th NFor example, the corrected overheat reference value Th calculated based on the temperature value T' of each of the multiple corrected diagnostic points N-5, N-4, N-3, N-2 and N-1 is N 'Assume 32.5℃.

[0118] Next, return to the reference Figure 3 The control unit 35 calculates the temperature value T measured at the Nth diagnosis point by N and overheat reference value Th N The comparison is performed to diagnose whether an overheating event has occurred in the battery 10 ( S400 ).

[0119] In step S400, the control unit 35 determines the temperature value T measured at the Nth diagnosis point. N Whether it exceeds the overheating reference value Th N (S410).

[0120] In step S400, as a result of the determination, when the temperature value T N Exceeding the overheating reference value Th N When (S410, YES), the control unit 35 diagnoses that an overheating event has occurred in the battery 10 (S420).

[0121] In step S400, as a result of the determination, when the temperature value T N Less than or equal to the overheat reference value Th N When the temperature of the battery 10 is in a normal state (S400, No), the control unit 35 diagnoses that the temperature of the battery 10 is in a normal state (S430).

[0122] For example, referring to Table 1, the temperature value T measured at the Nth diagnostic point is N Assume it is 30℃. Since the temperature value T corresponding to the Nth diagnosis point N (30℃) is less than the overheat reference value Th corresponding to the Nth diagnosis point N (32.5°C), the control unit 35 can diagnose that no overheating event has occurred. That is, the control unit 35 can diagnose that the temperature of the object is in a normal state.

[0123] Figure 6 is an example diagram showing temperature changes of a non-defective battery in a charging mode. Figure 7 is an example diagram showing temperature changes of a defective battery in a charging mode.

[0124] exist Figure 6 and Figure 7 , the X-axis represents time (seconds), and the Y-axis represents temperature (° C.).

[0125] Reference Figure 6, which is an example graph showing temperature changes over time when a non-defective battery is charged at various external temperatures.

[0126] For example, when the air temperature is 25° C., in a charging mode in which the battery 10 is charged with power from an external device, a temperature change of the battery 10 over time may correspond to the first graph T A As another example, when the battery 10 is charged at an air temperature of 30° C., the temperature variation of the battery 10 over time may correspond to the second graph T B Similarly, when the air temperature is 35°C and 40°C, the temperature change of the battery 10 may correspond to the third graph T C And the fourth figure T D .

[0127] That is, in the case of the battery 10 in a normal state according to a predetermined standard or an unused new battery 10, when the external temperature changes, the starting temperature value may be different, but as shown in FIG. Figure 6 As shown, the change in temperature over time (ie, the slope) may be constant.

[0128] Reference Figure 7 , which is an example graph showing a change in temperature over time when a defective battery is charged at a predetermined external temperature, is a graph derived from an experiment.

[0129] In this case, the solid line FL is the actually measured battery temperature, and the dotted line DL drawn close to the solid line (FL) is the baseline. According to an embodiment, the baseline may be constructed by connecting the overheat reference values ​​calculated at each diagnosis point. Figure 6 and Figure 7 , the temperature change of defect-free battery can form Figure 6 The straight line graph shown, however, the temperature variation of the defective battery can form Figure 7 The graph shown.

[0130] Conventionally, when the temperature of the battery 10 exceeds a fixed overheat reference value (eg, 60° C.), an overheat event is diagnosed at that point. Figure 7 Conventionally, the occurrence of an overheating event of the battery 10 can be diagnosed for the first time at the second point AD2.

[0131] However, based on the overheating diagnosis method according to the embodiment, the occurrence of an overheating event can be pre-diagnosed before the temperature of the battery 10 exceeds a fixed overheating reference value (e.g., 60° C.). As a result of the experiment, the occurrence of an overheating event of the battery 10 is first diagnosed at the first point AD1. Specifically, as a result of the diagnosis, the overheating event is continuously diagnosed at each diagnosis point from the first point AD1 where the solid line FL exceeds the dotted line DL to the second point AD2.

[0132] Reference Figure 6 The experimental results show a time difference of about 1000 seconds (about 16 minutes) between the first point AD1 and the second point AD2. Based on the overheating diagnosis method according to the embodiment, the occurrence of an overheating event of the battery 10 can be known in advance, which has the advantage of being able to prepare countermeasures.

[0133] Although the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by ordinary technicians in the field to which the present disclosure belongs to belong to the scope of the present disclosure.

Claims

1. An overheating diagnostic device, comprising: a measuring unit configured to measure a temperature of an object; a storage unit configured to store the temperature value measured by the measuring unit; as well as a control unit configured to: extract, at each diagnosis point for diagnosing overheating of the object, a plurality of previous diagnosis points corresponding to a predetermined number of samples based on the diagnosis point; calculating a moving average value that is an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; calculating a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points; calculating an overheat reference value by adding the error value to the moving average value when an error value calculated by multiplying the standard deviation average value by a predetermined multiple is greater than or equal to a predetermined error reference value; And diagnosing the occurrence of an overheating event of the object by comparing the temperature value measured at each diagnosis point with the overheating reference value calculated at each diagnosis point.

2. The overheating diagnostic device according to claim 2, wherein: The control unit When the error value is less than the error reference value, the plurality of temperature values ​​are corrected according to a result of comparing each of the plurality of temperature values ​​corresponding to the plurality of diagnosis points with the moving average value, and the overheat reference value is calculated based on a plurality of corrected temperature values.

3. The overheat diagnosis device according to claim 2, wherein: The control unit For each of the plurality of temperature values, the temperature value is corrected by adding a predetermined correction value to the temperature value when the temperature value is greater than the moving average value, and the temperature value is corrected by subtracting the correction value from the temperature value when the temperature value is less than the moving average value.

4. The overheating diagnostic device according to claim 1, wherein: the control unit, When the measured temperature value exceeds the overheat reference value, It is diagnosed that the overheating event has occurred in the object.

5. A battery system comprising: A battery, the battery comprising a plurality of battery cells; a measuring unit configured to measure a temperature of the battery; a storage unit configured to store the temperature value measured by the measuring unit; as well as a control unit configured to: at each diagnosis point for diagnosing overheating of the battery, extract a plurality of previous diagnosis points corresponding to a predetermined number of samples based on the diagnosis point; calculating a moving average value that is an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; calculating a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points; calculating an overheat reference value by adding the error value to the moving average value when an error value calculated by multiplying the standard deviation average value by a predetermined multiple is greater than or equal to a predetermined error reference value; And diagnosing the occurrence of an overheat event of the battery by comparing the temperature value measured at each diagnosis point with the overheat reference value calculated at each diagnosis point.

6. The battery system according to claim 5, wherein: The control unit When the error value is less than the error reference value, the plurality of temperature values ​​are corrected according to a result of comparing each of the plurality of temperature values ​​corresponding to the plurality of diagnosis points with the moving average value, and the overheat reference value is calculated based on a plurality of corrected temperature values.

7. The battery system according to claim 6, wherein: The control unit For each of the plurality of temperature values, the temperature value is corrected by adding a predetermined correction value to the temperature value when the temperature value is greater than the moving average value, and the temperature value is corrected by subtracting the predetermined correction value from the temperature value when the temperature value is less than the moving average value.

8. The battery system according to claim 5, wherein: the control unit, When the measured temperature value exceeds the overheat reference value, It is diagnosed that the overtemperature event has occurred in the battery.

9. An overheating diagnosis method, comprising: a temperature data collecting step of receiving a temperature value as a temperature measurement value of the battery from a measuring unit at a predetermined diagnosis point for diagnosing overheating of the battery, the battery comprising a plurality of battery cells; a sample group determination step of extracting a plurality of previous diagnostic points corresponding to the number of samples based on the diagnostic points; an overheat reference value calculation step, comprising: a step of calculating a moving average value as an average of a plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; a step of calculating a standard deviation average value as an average of a plurality of standard deviations corresponding to each of the plurality of diagnosis points, and calculating an error value by multiplying the standard deviation average value by a predetermined multiple; and a step of calculating an overheat reference value by adding the error value to the moving average value when the calculated error value is greater than or equal to a predetermined error reference value; and The overheat diagnosis step diagnoses the occurrence of an overheat event of the battery by comparing the temperature value with the overheat reference value.

10. The overheating diagnosis method according to claim 9, wherein: The overheat reference value calculation step further includes, when the error value is less than the error reference value: a temperature value correction step of correcting the plurality of temperature values ​​according to a result of comparing each of the plurality of temperature values ​​corresponding to the plurality of diagnosis points with the moving average value, and In the superheat reference value calculation step, The superheat reference value is calculated based on a plurality of corrected temperature values.

11. The overheating diagnosis method according to claim 10, wherein: The temperature value correction step comprises: a step of extracting the plurality of temperature values ​​corresponding to each of the plurality of diagnosis points; the step of comparing each temperature value of the plurality of temperature values ​​with the moving average; a first correction step of correcting the temperature value by adding a predetermined correction value to the temperature value when the temperature value is greater than or equal to the moving average value as a result of the comparison; and The second correction step is to correct the temperature value by subtracting the predetermined correction value from the temperature value when the temperature value is less than the moving average value.

12. The overheating diagnosis method according to claim 9, wherein: The overheating diagnosis step comprises: The step of comparing the measured temperature value with the overheat reference value; a first diagnostic step of diagnosing that the overheat event has occurred in the battery when the measured temperature value exceeds the overheat reference value as a result of the comparison; and The second diagnosis step is to diagnose the battery as being in a normal state where no overheating event occurs when the measured temperature value is less than or equal to the overheating reference value as a result of the comparison.

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