Apparatus and method for diagnosing a battery

Abstract

A battery diagnosis device according to an embodiment of the present application includes: a voltage measurement unit configured to measure a voltage of a battery cell; a fitted value calculation unit configured to calculate a fitted voltage of the battery cell in a rest interval after charging and discharging of the battery cell; and a diagnosis unit configured to diagnose an abnormality of the battery cell by comparing a measured voltage measured by the voltage measurement unit with the fitted voltage calculated by the fitted value calculation unit with respect to the rest interval of the battery cell.

Description

TECHNICAL FIELD

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0096308, filed July 31, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0004] The present application relates to a battery diagnosis apparatus and method for diagnosing whether a battery is abnormal by using normal behavior simulation of a battery cell voltage. BACKGROUND

[0005] Recently, research and development on secondary batteries have been actively conducted. Here, the secondary battery includes a battery capable of charging and discharging, and includes all conventional Ni / Cd batteries, Ni / MH batteries, and recent lithium ion batteries. Among the secondary batteries, the lithium ion batteries have an advantage in that their energy density is much higher than that of the conventional Ni / Cd batteries and Ni / MH batteries, and in addition, a lithium ion battery capable of being manufactured to be small in size and light in weight, so they are used as a power source of a mobile device. In addition, the lithium ion battery has attracted attention as a next-generation energy storage medium due to its extended use as a power source of an electric vehicle.

[0006] In addition, the secondary battery is generally used as a battery pack including a battery module in which a plurality of battery cells are connected in series and / or in parallel. Then, the state and operation of the battery pack are managed and controlled by a battery management system.

[0007] Generally, in the case of an energy storage system (ESS), a list for performing diagnosis is provided to prevent a fire. The diagnosis list includes data on voltage, current, temperature, power, etc., and a diagnosis item of each battery cell is mainly performed with respect to overvoltage and undervoltage.

[0008] However, in reality, there is a case where a defect occurs other than an upper section or a lower section of a battery cell voltage, and a fire often occurs even when an overvoltage or undervoltage warning does not occur. Therefore, a new diagnosis item is needed to prevent these problems. SUMMARY

[0009] [TECHNICAL PROBLEM]

[0010] The present application has been designed to solve the above problems, and an object of the present application is to provide an apparatus and method for diagnosing a battery to detect abnormal behavior of a battery cell by simulating a shape of a voltage during a rest period after charging and discharging of the battery cell and comparing it with an actually measured voltage.

[0011] [Technical Solution]

[0012] A battery diagnosis device according to an embodiment of the present application includes a voltage measurement unit configured to measure a voltage of a battery cell, a fitted value calculation unit configured to calculate a fitted voltage of the battery cell in a rest interval after charging and discharging of the battery cell, and a diagnosis unit configured to diagnose an abnormality of the battery cell by comparing a measured voltage measured by the voltage measurement unit and the fitted voltage calculated by the fitted value calculation unit with respect to the rest interval of the battery cell.

[0013] A battery diagnosis method according to an embodiment of the present application includes measuring a voltage of a battery cell, calculating a fitted voltage of the battery cell in a rest interval after charging and discharging of the battery cell, and diagnosing an abnormality of the battery cell by comparing the measured voltage of the battery cell and the fitted voltage of the battery cell with respect to the rest interval of the battery cell.

[0014] [Effects of the Invention]

[0015] According to the battery diagnosis device and method of the present application, an abnormal behavior of a battery cell can be detected by simulating a shape of a voltage during a rest period after charging and discharging of the battery cell and comparing it with an actually measured voltage. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a block diagram showing a configuration of a general battery rack.

[0017] Figure 2 is a block diagram showing a configuration of a battery diagnosis device according to an embodiment of the present application.

[0018] Figure 3 is a view showing an actual voltage shape, a voltage shape of a battery cell calculated by a battery diagnosis device according to an embodiment of the present application, and a voltage shape calculated according to a related art.

[0019] Figure 4 is a graph illustrating a change in a voltage shape according to a fitted time in a battery diagnosis device according to an embodiment of the present application.

[0020] Figure 5 is a graph illustrating a current consumption of a battery management system (MBMS) of a battery module according to an embodiment of the present application.

[0021] Figure 6 is a graph comparing a voltage shape calculated by a battery diagnosis device according to an embodiment of the present application and an actual voltage value.

[0022] Figure 7is a flowchart illustrating a method for diagnosing a battery according to an embodiment of the present application.

[0023] Figure 8 is a block diagram illustrating a hardware configuration of a battery diagnosis apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] Hereinafter, various embodiments of the present application will be described in detail with reference to the accompanying drawings. In this document, the same reference numerals are used for the same components throughout the drawings, and repetitive description of the same components is omitted.

[0025] For various embodiments of the present application disclosed in this document, a specific structural or functional description has been exemplified only for the purpose of describing embodiments of the present application, and various embodiments of the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments described in this document.

[0026] Expressions such as "first", "second", "1st", or "2nd" used in various embodiments can modify various elements regardless of their order and / or importance, and do not limit the corresponding elements. For example, a first component can be referred to as a second component without departing from the scope of the present application, and similarly, a second component can be renamed and referred to as a first component.

[0027] The terms used in this document are only used to describe specific embodiments, and can not be intended to limit the scope of other embodiments. Unless otherwise specified, a singular form of a term can include a plural form.

[0028] All terms used herein, including technical or scientific terms, can have the same meaning as commonly understood by one of ordinary skill in the art. Unless explicitly defined in this document, terms defined in a common dictionary can be interpreted to have the same or similar meaning as in the context of the relevant art, and not to be interpreted as an ideal or overly formal meaning. In some cases, even the term defined in this document cannot be interpreted to exclude embodiments of the present application.

[0029] Figure 1 is a block diagram showing a configuration of a general battery rack.

[0030] Reference Figure 1 , which schematically shows a battery control system according to an embodiment of the present application, the battery control system including a battery rack 1 and a superior controller 2 included in a superior system.

[0031] As Figure 1As shown, the battery rack 1 includes: a battery module 10 that is configured of one or more battery cells and is capable of charging and discharging; a switching unit 14 that is connected in series to the (+) terminal side or the (-) terminal side of the battery module 10 to control the charge / discharge current of the battery module 10; and a battery management system 20 (e.g., MBMS) for controlling and managing the voltage, current, temperature, etc. of the battery rack 1 to prevent overcharging and overdischarging.

[0032] Here, the switching unit 14 is a semiconductor switching element for controlling the current for charging or discharging of the plurality of battery modules 10, and at least one MOSFET, or a relay, a magnetic contactor, etc. can be used, for example, according to the specifications of the battery rack 1.

[0033] In addition, in order to monitor the voltage, current, temperature, etc. of the battery rack 1, the battery management system 20 can measure or calculate the voltage and current of the gate, source, and drain of the semiconductor switching device. In addition, the battery management system 20 can measure the current, voltage, temperature, etc. of the battery rack 1 using the sensor 12 disposed adjacent to the semiconductor switching element. Here, the sensor 12 can correspond to a voltage measurement unit to be described later.

[0034] The battery management system 20 is an interface for receiving values obtained by measuring the above-described various parameters, and can include a plurality of terminals and a circuit connected to the terminals to process the input values. In addition, the battery management system 20 can control the turn-on / off of the switching unit 14, e.g., a MOSFET, and can be connected to the battery module 10 to monitor the state of each battery module 10.

[0035] Meanwhile, in the battery management system 20 of the present application, the voltage in the rest interval after charging and discharging of the battery cell can be calculated by a separate program as described below. In addition, by comparing the calculated voltage with the voltage detected by the sensor 12, it is possible to diagnose whether the battery cell is abnormal.

[0036] The upper controller 2 can transmit a control signal for the battery module 10 to the battery management system 20. Accordingly, the operation of the battery management system 20 can be controlled based on the signal applied from the upper controller. On the other hand, the battery cell of the present application can be a configuration included in the battery module 10 used in an energy storage system (ESS). And in this case, the upper controller 2 can be an ESS controller. However, the battery rack 1 is not limited to such a use.

[0037] Since the configuration of the battery rack 1 and the configuration of the battery management system 20 are known configurations, a more detailed description thereof will be omitted.

[0038] Figure 2is a block diagram illustrating a configuration of a battery diagnostic device according to an embodiment of the present application.

[0039] Referring to Figure 2 The battery diagnostic device 200 according to an embodiment of the present application can include a voltage measurement unit 210, a fitted voltage calculation unit 220, and a diagnostic unit 230.

[0040] The voltage measurement unit 210 can measure a voltage of each battery cell. In this case, the voltage measurement unit 210 can measure the voltage at a set time interval. In addition, the voltage measurement unit 210 can measure a current flowing through the battery cell. Accordingly, it can be determined whether the battery cell is in a rest interval (i.e., an interval in which the current is 0) after charging and discharging of the battery cell through a current value of the battery cell measured by the voltage measurement unit 210.

[0041] The fitted voltage calculation unit 220 can calculate a fitted voltage of the battery cell in a rest interval after charging and discharging of the battery cell. Specifically, the fitted voltage calculation unit 220 calculates the fitted voltage of the battery cell by exponentially fitting a voltage of the battery cell in a first interval with respect to a rest interval after charging and discharging of the battery cell. For example, the first interval can be an interval having an IR drop.

[0042] In addition, the fitted voltage calculation unit 220 can calculate the fitted voltage of the battery cell by linearly fitting a voltage of the battery cell in a second interval after the first interval. For example, the second interval can be a stable interval in which the voltage is maintained or linearly decreased during a rest of the battery cell.

[0043] The fitted voltage calculation unit 220 can preset a coefficient of an exponential part of a calculation equation for the fitted voltage of the battery cell in the rest interval after charging and discharging of the battery cell to be greater than or less than 0. For example, the calculation equation in the above-described first interval of the fitted voltage can be expressed as V1 = a*exp(b*X) + c, and in this case, a value a that is a coefficient of the exponential part can be set to be greater than 0. Accordingly, it is possible to more clearly show a shape of the fitted voltage of the battery cell.

[0044] In addition, the fitted voltage calculation unit 220 can calculate the fitted voltage of the battery cell by reflecting power consumed by a battery management system (module battery management system (MBMS)) of a battery module. In this case, the fitted voltage calculation unit 220 can calculate the fitted voltage of the battery cell by linearly decreasing the voltage of the battery cell in the above-described second interval with a slope corresponding to the power consumed by the battery management system of the battery module. For example, the power consumption of the battery management system can be converted using an open circuit voltage (OCV) table that defines a relationship between a battery capacity and a voltage.

[0045] Therefore, regarding the fitting voltage calculation unit 220, in the rest interval after charging and discharging of the battery cell, by dividing the interval in which the voltage shape of the battery cell appears in an exponential form and the interval in which the voltage shape appears linearly to calculate the fitting voltage, it is possible to more accurately detect abnormal voltage behavior of the battery cell compared to the case in which it is fitted in one way as in the related art.

[0046] Meanwhile, the fitting voltage calculation unit 220 can adjust the number of voltage data measured by the voltage measurement unit 210 based on the sampling time of the measured voltage data of the battery cell. For example, the number of voltage data is adjusted such that if the sampling time of the voltage data is 1 minute, the number is 30, and if the sampling time is 2 minutes, the number is 15, and if the sampling time is 1 second, the number is 1800, etc., and the exponential fitting time Tau can be set accordingly.

[0047] In addition, when the measurement interval of the voltage data of the battery cell measured by the voltage measurement unit 210 is greater than or equal to a preset time, the fitting voltage calculation unit 220 can separate the measured voltage data. For example, the fitting voltage calculation unit 220 can calculate the fitting voltage by separating the corresponding data when the logarithmic phase time interval of the voltage data is 1 hour or more. That is, when the logarithmic interval of the voltage data is 1 hour or more, it is possible to calculate the fitting voltage for each interval by dividing it into a plurality of intervals based on the corresponding part.

[0048] Regarding the rest interval after charging and discharging of the battery cell, the diagnosis unit 230 can diagnose the abnormality of the battery cell by comparing the measured voltage measured by the voltage measurement unit 210 with the fitting voltage calculated by the fitting voltage calculation unit 220. Specifically, when the difference between the measured voltage and the fitting voltage in the rest interval of the battery cell is equal to or greater than a preset first reference value, the diagnosis unit 230 can determine that an abnormality has occurred in the battery cell. At this time, by comparing the maximum value of the difference between the measured voltage and the fitting voltage with the first reference value, it is possible to determine whether the battery is abnormal.

[0049] In addition, when the standard deviation of the difference between the measured voltage measured by the voltage measurement unit 210 and the fitting voltage calculated by the fitting voltage calculation unit 220 with respect to the rest interval after charging and discharging of the battery cell is equal to or greater than a preset second reference value, the diagnosis unit 230 can determine that an abnormality has occurred in the battery cell. In this case, the standard deviation can indicate the error of each battery cell at a certain time. For example, it is possible to determine whether the battery cell is abnormal by comparing the standard deviation of the maximum value among the difference between the measured voltage and the fitting voltage with the second reference value.

[0050] With respect to the rest interval after charging and discharging of the battery cell, the diagnosis unit 230 can determine that an abnormality in which the difference between the measured voltage measured by the voltage measurement unit 210 and the fitted voltage calculated by the fitted voltage calculation unit 220 is greater than or equal to a preset first reference value has occurred two or more times in the battery cell. In addition, as described above, the diagnosis unit 230 can determine that an abnormality in which the standard deviation of the difference between the measured voltage and the fitted voltage is greater than a second reference value has occurred two or more times in the battery cell.

[0051] Meanwhile, although not shown in FIG. 1, Figure 2 The battery diagnosis apparatus 200 according to an embodiment of the present application can include a storage unit. The storage unit can store voltage and current measurement data of the battery cell, calculated fitted voltage data, power consumption data of the battery management system, etc. However, the storage unit does not necessarily have to be included in the battery diagnosis apparatus 200, and the storage unit can be included in an external server to transmit and receive data through a separate communication module (not shown).

[0052] In addition, the battery diagnosis apparatus 200 according to an embodiment of the present application can further include a display unit (not shown). Accordingly, the battery diagnosis apparatus 200 according to an embodiment of the present application can express the voltage or current shape measured by the voltage measurement unit 210 or the shape of the fitted voltage calculated by the fitted voltage calculation unit 220 to a user in a chart form through the display unit. In addition, the display unit can be provided with a user interface (e.g., a touchpad, etc.) to receive an input of the user.

[0053] Accordingly, according to the battery diagnosis apparatus based on an embodiment of the present application, it is possible to detect abnormal behavior of the battery cell by simulating the shape of the voltage during the rest period after charging and discharging of the battery cell and comparing it with the actually measured voltage.

[0054] Figure 3 is a view showing an actual voltage shape, a voltage shape of the battery cell calculated by the battery diagnosis apparatus according to an embodiment of the present application, and a voltage shape calculated according to the related art. Referring to Figure 3 , the x-axis indicates time (minute), and the y-axis indicates voltage (V). At this time, Figure 3 The graph of FIG. 1 shows a voltage shape fitted in an exponential form using recorded voltage data after excluding trickle charging (i.e., operating charging in a dotted form to match the SOC 100) in the rest interval after charging.

[0055] As Figure 3As shown, it can be seen that the actual voltage in the rest period after charging the battery cell initially decreases in a manner similar to an exponential function, and appears to be almost constant between about 8 minutes and 25 minutes, before decreasing linearly again.

[0056] In this regard, it can be seen that when the voltage is simply linearly fitted as in conventional methods, the error with the actual voltage is large. Therefore, regarding the battery diagnostic device according to an embodiment of the present invention, in the resting voltage after charging or discharging, by fitting the voltage exponentially in the interval where the voltage decreases rapidly, and by linearly fitting the voltage in the interval where polarization is resolved, the voltage in the resting interval can be calculated more accurately than in the prior art. In this case, the coefficient of the exponential part in the voltage fitting equation is set to be greater than 0, and the exponential fitting time can be freely adjusted according to the sampling time.

[0057] In addition, relative to the above-mentioned Figure 3 The linear interval, considering the power consumption of the module battery management system (MBMS), can be expressed in a linearly decreasing form by reflecting the voltage reduction caused by the power supplied to the battery management system, even if no battery charging or discharging occurs.

[0058] Figure 4 This is a diagram illustrating the change in voltage shape in a battery diagnostic device according to an embodiment of the present invention, based on fitting time.

[0059] refer to Figure 4 The figure shows the voltage in the rest interval after discharge when the Tau value corresponding to the exponential fitting time of the voltage is set to 15, 25, 35, 45 and 55 respectively. Figure 4 This shows a comparison between the actual measured voltage data and the fitted voltage data after excluding the trickle charge portion during the rest period following discharge. Figure 4 In each chart, the x-axis represents time (2 minutes), while the y-axis represents voltage (V).

[0060] like Figure 4 As shown, it can be seen that as the Tau value decreases (e.g., Tau = 15), the actual voltage and the fitted voltage tend to match at the beginning of the graph, while conversely, as the Tau value increases (e.g., Tau = 55), the actual voltage and the fitted voltage tend to match at the end of the graph.

[0061] Therefore, since the range between the actual voltage and the fitted voltage varies depending on the Tau value, in the battery diagnostic device according to an embodiment of the present invention, the Tau value can be appropriately set by taking into account the relaxation time instead of fixing the exponential fitting time to a constant value. For example, in the battery diagnostic device according to an embodiment of the present invention, the Tau value is set to 15 in the rest period after charging. Considering that the rest period after discharging is longer than the rest period after charging and the trend of voltage increase at the later stage, the Tau value can be set to 30, which is greater than the rest period after charging. However, the Tau value in the battery diagnostic device of the present invention is not limited to this and can be set to an appropriate value in some cases.

[0062] Figure 5 This is a diagram illustrating the current consumption of the battery management system (MBMS) of a battery module according to an embodiment of the present invention.

[0063] After a battery cell is charged or discharged, the voltage may drop even during the rest period when there is no current flow. This is mainly due to the voltage drop caused by the current consumption of the battery management system.

[0064] Therefore, in the battery diagnostic device according to an embodiment of the present invention, the fitted voltage of a battery cell in the rest period after charging and discharging can be calculated by taking into account the influence of the current consumption of the battery management system (e.g., MBMS). To reflect the influence of the current consumption of the battery management system, for example, current consumption values ​​measured at the ESS development center can be used.

[0065] In this regard, refer to Figure 5 (a) shows the average current consumption measured for a multi-module battery management system. Figure 5 In (a), the x-axis represents samples #1 to #14, and the y-axis represents the current consumption (mA) of each sample. Figure 5 As shown in (a), there are some differences for each sample of each battery management system, but the current consumption of the battery management system is in the range of 28.20 mA and 30.27 mA, and the average current consumption is 29.24 mA, indicating that the deviation is not significant.

[0066] Additionally, refer to Figure 5 Figure (b) shows the peak and average current consumption of the battery management system when the voltage of the individual battery cells is 3V, 3.7V, and 4.2V. Figure 5 As shown in (b), the current consumption of the battery management system increases with the increase of the voltage of the individual battery cells, but the difference is relatively small, with a maximum value of 0.3mA.

[0067] Therefore, since the current consumption of the battery management system in the battery diagnostic device according to an embodiment of the present invention does not have relatively large variations and remains almost constant even when the voltage of the battery cell changes, the fitted voltage can be calculated by setting the current consumption of the battery management system to a constant value (e.g., an upper limit of 30.27 mA). For example, the value corresponding to the current consumption of the battery management system can be used as the slope, and the voltage in the resting period can be linearly reduced after the charging and discharging of the battery cell.

[0068] Figure 6 It is a graph comparing the voltage shape calculated by the battery diagnostic device according to an embodiment of the present invention with the actual voltage value. Figure 6 The x-axis represents time, and the y-axis represents the voltage of a specific battery cell included in the non-operating battery rack.

[0069] refer to Figure 6 In a scenario where multiple battery racks in the battery bank are in operation while some are not, it shows that the actual voltage of the individual cells in the non-operational battery racks dropped by approximately 70mV and 50mV respectively over 15 days.

[0070] Therefore, even if the battery rack is not in operation, the actual voltage may often drop more than the fitted voltage over a long period of time. However, the difference due to the reduced voltage is approximately 50mV to approximately 70mV, and the maximum error is only 0.049. Moreover, in system analysis, considering the voltage reduction due to current consumption by the battery management system, this can be considered within the normal range.

[0071] Figure 7 This is a flowchart illustrating a method for diagnosing a battery according to an embodiment of the present invention.

[0072] refer to Figure 7 In the battery diagnostic method according to an embodiment of the present invention, the voltage of a single battery cell is first measured (S710). In this case, during operation S710, the voltage can be measured at regular time intervals. Furthermore, although in Figure 6 As not shown in the diagram, in operation S710, it can be determined whether a battery cell is in a resting phase after charging or discharging—that is, a phase where the current is 0—by measuring the current flowing through the battery cell.

[0073] Then, after charging and discharging the battery cell, the fitted voltage of the battery cell in the rest period is calculated (S720). Specifically, in operation S720, relative to the rest period after charging and discharging the battery cell, the fitted voltage of the battery cell can be calculated by fitting the voltage of the battery cell in a preset first interval (e.g., IR drop interval) in an exponential manner. In addition, in the second interval after the first interval (e.g., voltage maintenance or linear decrease interval), the fitted voltage of the battery cell can be calculated by linearly fitting the voltage of the battery cell.

[0074] Specifically, in operation S720, the fitted voltage of a single battery cell can be calculated by reflecting the power consumed by the battery management system (MBMS) of the battery module. In this case, the fitted voltage of a single battery cell can be calculated in the aforementioned second interval by linearly decreasing the voltage of the single battery cell with a slope corresponding to the power consumed by the battery management system of the battery module.

[0075] Then, it is determined whether the difference between the voltage measured during the rest period of the battery cell and the fitted voltage of the battery cell is equal to or greater than the reference value (first reference value) (S730). If the difference is less than the reference value (No), the process returns to operation S710 again.

[0076] Simultaneously, when the difference between the measured voltage and the fitted voltage of a battery cell is equal to or greater than the reference value (Yes), an abnormality can be diagnosed in the corresponding battery cell (S740). In this case, whether the battery cell is abnormal can be determined by comparing the maximum value of the difference between the measured voltage and the fitted voltage with the aforementioned reference value.

[0077] In addition, although in Figure 6 As not shown, relative to the rest period after charging and discharging a battery cell, when the standard deviation of the difference between the measured voltage and the calculated fitted voltage of a battery cell is equal to or greater than a preset reference value (second reference value), it can be determined that an anomaly has occurred in the battery cell. For example, whether a battery cell is abnormal can be determined by comparing the standard deviation of the maximum value of the difference between the measured voltage and the fitted voltage with the aforementioned reference value.

[0078] Therefore, according to the battery diagnostic method based on embodiments of the present invention, abnormal behavior of a battery cell can be detected by simulating the shape of the voltage during the rest period after charging and discharging of the battery cell and comparing it with the actual measured voltage.

[0079] Figure 8 This is a block diagram illustrating the hardware configuration of a battery diagnostic device according to an embodiment of the present invention.

[0080] refer to Figure 8According to an embodiment of the present invention, the battery diagnostic device 800 may include an MCU 810, a memory 820, an input / output I / F 830, and a communication I / F 840.

[0081] The MCU 810 can be a processor that runs various programs (e.g., battery diagnostic programs, fitting voltage calculation programs, etc.) stored in the memory 820. These programs process various data used to calculate the resting voltage of individual battery cells and perform the aforementioned operations. Figure 2 The function.

[0082] The memory 820 can store various programs related to calculating the fitted voltage of individual battery cells, diagnosing anomalies, etc. Additionally, the memory 820 can store various data, such as measured voltage and current data of individual battery cells, and current consumption of the battery management system.

[0083] Multiple such memories 820 can be configured as needed. Memory 820 can be volatile or non-volatile. Memory 820 as volatile memory can include RAM, DRAM, SRAM, etc. Memory 820 as non-volatile memory can be ROM, PROM, EAROM, EPROM, EEPROM, flash memory, etc. The examples of memory 820 listed above are merely examples and are not limited to these examples.

[0084] The Input / Output I / F 830 can provide an interface for sending and receiving data between input devices (not shown) such as a keyboard, mouse, and touch panel and output devices such as a display (not shown) and MCU 810.

[0085] The Communication I / F 840 is configured to send and receive various types of data with a server and can be a variety of devices capable of supporting wired or wireless communication. For example, the Communication I / F 840 can be used to send / receive programs for diagnosing and calculating the fitted voltage of individual battery cells to / from a separately configured external server.

[0086] In this way, the computer program according to an embodiment of the invention is recorded in memory 820 and processed by MCU 810, such that it can be implemented, for example, to execute Figure 2 The module of each functional block shown in the diagram.

[0087] In the foregoing, even though all components constituting embodiments of the present invention are described as operating in combination or in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the purpose of the present invention, all constituent elements can be selectively combined and operated in one or more combinations.

[0088] Furthermore, unless otherwise stated, terms such as “comprising,” “consisting of,” or “having” as described above imply that the corresponding constituent components can be present, and it should be interpreted that other components may be further included rather than excluded. Unless otherwise defined, all terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Commonly used terms, such as those defined in dictionaries, should be interpreted as consistent with their meaning in the context of the relevant art, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this invention.

[0089] The above description is merely illustrative of the technical concept of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the invention. Therefore, the embodiments disclosed in this invention are not intended to limit the technical concept of the invention, but rather to illustrate it, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention should be interpreted through the following claims, and all technical concepts within their equivalents should be interpreted as being included within the scope of this invention.

Claims

1. A battery diagnostic device, comprising: A voltage measurement unit configured to measure the voltage of a single battery cell; A fitting value calculation unit is configured to calculate the fitting voltage of the battery cell during the rest interval after charging and discharging. as well as A diagnostic unit is configured to diagnose abnormalities in the battery cell by comparing a measured voltage measured by the voltage measurement unit with a fitted voltage calculated by the fitted value calculation unit, relative to the resting range of the battery cell. The fitting value calculation unit reflects the power consumed by the battery management system to calculate the fitting voltage of the battery cell.

2. The battery diagnostic device according to claim 1, wherein, The fitting value calculation unit calculates the fitted voltage of the battery cell by performing an exponential fit on the voltage of the battery cell in a preset first interval relative to the rest interval after the charging and discharging of the battery cell, and calculates the fitted voltage of the battery cell by performing a linear fit on the voltage of the battery cell in a second interval after the first interval.

3. The battery diagnostic device according to claim 2, wherein, The fitting value calculation unit sets the coefficient of the exponential part of the fitting voltage to be greater than 0.

4. The battery diagnostic device according to claim 1, wherein, The fitting value calculation unit calculates the fitting voltage of the battery cell by linearly decreasing the voltage of the battery cell at a slope corresponding to the power consumed by the battery management system.

5. The battery diagnostic device according to claim 1, wherein, The fitting value calculation unit adjusts the number of measured voltage data based on the sampling time of the measured voltage data of the battery cell.

6. The battery diagnostic device according to claim 1, wherein, When the measurement interval of the measured voltage data of the battery cell is greater than a preset time, the fitting value calculation unit separates the measured voltage data.

7. The battery diagnostic device according to claim 1, wherein, When the difference between the measured voltage measured by the voltage measurement unit and the fitted voltage calculated by the fitted value calculation unit relative to the rest interval of the battery cell is equal to or greater than a preset first reference value, the diagnostic unit determines that an abnormality has occurred in the battery cell.

8. The battery diagnostic device according to claim 7, wherein, When the standard deviation of the difference between the measured voltage measured by the voltage measurement unit and the fitted voltage calculated by the fitted value calculation unit relative to the rest interval of the battery cell is equal to or greater than a preset second reference value, the diagnostic unit determines that an abnormality has occurred in the battery cell.

9. The battery diagnostic device according to claim 7, wherein, If the difference between the measured voltage measured by the voltage measurement unit and the fitted voltage calculated by the fitted value calculation unit within the rest interval relative to the battery cell occurs two or more times, equal to or greater than a preset first reference value, the diagnostic unit determines that an abnormality has occurred in the battery cell.

10. A battery diagnostic method, comprising: Measure the voltage of individual battery cells; Calculate the fitted voltage of the battery cell during the rest period after charging and discharging; as well as Abnormalities in a battery cell are diagnosed by comparing its measured voltage with its fitted voltage relative to the cell's resting range. The calculation of the fitted voltage of the battery cell includes reflecting the power consumed by the battery management system to calculate the fitted voltage of the battery cell.

11. The method according to claim 10, wherein, The calculation of the fitted voltage of the battery cell includes: calculating the fitted voltage of the battery cell by performing an exponential fit on the voltage of the battery cell in a preset first interval relative to the rest interval after charging and discharging of the battery cell, and calculating the fitted voltage of the battery cell by performing a linear fit on the voltage of the battery cell in a second interval after the first interval.

12. The method according to claim 10, wherein, The calculation of the fitted voltage of the battery cell includes: calculating the fitted voltage of the battery cell by linearly decreasing the voltage of the battery cell at a slope corresponding to the power consumed by the battery management system.

13. The method according to claim 10, wherein, The diagnosis of the abnormality of the battery cell includes: determining that an abnormality has occurred in the battery cell when the difference between the measured voltage and the fitted voltage of the battery cell relative to the rest interval of the battery cell is equal to or greater than a preset first reference value.

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