Battery management apparatus and operation method therefor

Abstract

A battery management apparatus according to an embodiment disclosed in the present document includes: a temperature estimation unit for estimating the temperature of a battery on the basis of EIS data associated with the impedance of the battery; a data acquisition unit for acquiring measurement data associated with the measured temperature of the battery; and a temperature correction unit for correcting the estimated temperature of the battery to correspond to the measured temperature of the battery on the basis of at least one correction coefficient generated on the basis of the error between the measured temperature and the estimated temperature.

Description

Battery management device and its operating method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2024-0024149, filed February 20, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] One embodiment disclosed in this document relates to a battery management device and a method of operating the same.

[0005] Recently, active research and development has been conducted on secondary batteries. The term "secondary battery" refers to a rechargeable battery, encompassing both conventional Ni / Cd and Ni / MH batteries, as well as more recent lithium-ion batteries. Among secondary batteries, lithium-ion batteries boast a significantly higher energy density than conventional Ni / Cd and Ni / MH batteries. Furthermore, lithium-ion batteries can be manufactured in a compact and lightweight form, making them a popular power source for mobile devices. Recently, their use has expanded to include power sources for electric vehicles, drawing attention as a next-generation energy storage medium.

[0006] A battery management system (BMS) monitors battery temperature, voltage, and current, and controls battery operation based on the monitored battery status. Battery temperature is a critical variable affecting battery performance, and BMSs must be able to measure battery temperature more accurately.

[0007] To this end, if a temperature sensor for measuring the temperature of the battery is positioned in each battery cell, there is a problem of the internal space of the battery pack being reduced, and if the temperature of the battery is predicted through electrochemical impedance spectroscopy (EIS) of the battery pack, there is a problem of the accuracy of the predicted temperature being reduced.

[0008] One purpose of the embodiments disclosed in this document is to provide a battery management device and an operating method thereof that correct the temperature of a battery predicted through EIS analysis to correspond to the temperature of the battery actually measured.

[0009] The technical problems of the embodiments disclosed in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0010] A battery management device according to an embodiment disclosed in the present document may include a temperature estimation unit for estimating a temperature of a battery based on EIS data related to an impedance of the battery; a data acquisition unit for acquiring measurement data related to the measured temperature of the battery; and a temperature correction unit for correcting an estimated temperature of the battery to correspond to the measured temperature of the battery based on at least one correction coefficient generated based on an error between a measured temperature of the battery according to the measurement data and an estimated temperature of the battery.

[0011] According to one embodiment, the temperature compensation unit may compensate the estimated temperature of the battery to correspond to the measured temperature of the battery by using a compensation coefficient corresponding to each of a plurality of temperature ranges.

[0012] According to one embodiment, the temperature compensation unit may perform offset compensation by adding or subtracting an offset compensation coefficient, which is at least one compensation coefficient corresponding to each of the plurality of temperature sections, to the estimated temperature of the battery in each of the plurality of temperature sections, thereby compensating the estimated temperature of the battery to correspond to the measured temperature of the battery.

[0013] In one embodiment, the offset correction factor may be determined based on an absolute value of an error between the estimated temperature of the battery and the measured temperature of the battery in each of the plurality of temperature intervals.

[0014] According to one embodiment, the offset correction factor may correspond to an average value of the absolute values ​​of the errors in each of the plurality of temperature intervals.

[0015] In one embodiment, the offset correction factor may correspond to a median value of the absolute values ​​of the errors in each of the plurality of temperature intervals.

[0016] According to one embodiment, the temperature compensation unit may compensate the estimated temperature of the battery to correspond to the measured temperature of the battery by substituting the estimated temperature of the battery into a formula generated based on a slope compensation coefficient, which is one of at least one compensation coefficient corresponding to each of the plurality of temperature sections.

[0017] In one embodiment, the formula may be a linear function having as its slope an average rate of change in error between the measured temperature of the battery and the estimated temperature of the battery at each of the start and end points of each of the plurality of temperature intervals.

[0018] In one embodiment, the estimated temperature of the battery at the starting point of each of the plurality of temperature intervals may be corrected to correspond to the measured temperature of the battery.

[0019] According to one embodiment, when the estimated temperature of the battery corresponds to a preset temperature, the temperature compensation unit may compensate the estimated temperature of the battery to correspond to the measured temperature of the battery using a point compensation coefficient, which is one of the at least one compensation coefficient.

[0020] An operating method of a battery management device according to an embodiment disclosed in the present document may include: estimating a temperature of the battery based on EIS data related to an impedance of the battery; acquiring measurement data related to a measured temperature of the battery; and correcting the estimated temperature of the battery to correspond to the measured temperature of the battery based on at least one correction factor generated based on an error between a measured temperature of the battery according to the measurement data and an estimated temperature of the battery.

[0021] According to one embodiment, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery may include the step of dividing data related to the estimated temperature of the battery into a plurality of temperature sections; and the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery using a correction coefficient corresponding to each of the plurality of temperature sections.

[0022] According to one embodiment, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery includes the step of performing an offset correction by adding or subtracting an offset correction coefficient, which is one of at least one correction coefficient corresponding to each of the plurality of temperature sections, to the estimated temperature of the battery in each of the plurality of temperature sections; wherein the offset correction coefficient can be determined based on an absolute value of an error between the estimated temperature of the battery and the measured temperature of the battery in each of the plurality of temperature sections.

[0023] According to one embodiment, the offset correction factor may correspond to an average value or a median value of the absolute values ​​of the errors in each of the plurality of temperature intervals.

[0024] According to one embodiment, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery may include the step of generating a formula based on a slope correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature ranges; and the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery by substituting the estimated temperature of the battery into the formula.

[0025] In one embodiment, the formula corresponds to a linear function whose slope is an average rate of change between the error between the measured temperature of the battery and the estimated temperature of the battery at each of the start and end points of each of the plurality of temperature intervals, and the estimated temperature of the battery at the start point of each of the plurality of temperature intervals can be corrected to correspond to the measured temperature of the battery.

[0026] A battery management device according to an embodiment disclosed in this document can improve the accuracy of the temperature of a battery predicted through EIS analysis.

[0027] The effects according to the embodiments disclosed in this document are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art according to the disclosure of this document.

[0028] FIG. 1 is a drawing for explaining a battery management device according to an embodiment disclosed in this document.

[0029] FIG. 2 is a diagram for explaining temperature data according to an embodiment disclosed in this document.

[0030] FIG. 3a is a drawing for explaining offset correction according to an embodiment disclosed in this document.

[0031] FIG. 3b is a drawing for explaining offset correction according to an embodiment disclosed in this document.

[0032] FIG. 4a is a drawing for explaining slope correction according to an embodiment disclosed in this document.

[0033] FIG. 4b is a drawing for explaining slope correction according to an embodiment disclosed in this document.

[0034] FIG. 5a is a drawing for explaining point correction according to an embodiment disclosed in this document.

[0035] FIG. 5b is a drawing for explaining point correction according to an embodiment disclosed in this document.

[0036] FIG. 6 is a flowchart illustrating the operation of a battery management device according to an embodiment disclosed in this document.

[0037] Hereinafter, embodiments disclosed in this document will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components are given identical reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments disclosed in this document, detailed descriptions of related known structures or functions will be omitted if they are deemed to hinder understanding of the embodiments disclosed in this document.

[0038] In describing the components of the embodiments disclosed in this document, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components and do not limit the nature, order, or sequence of the components. In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments disclosed in this document belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this application.

[0039] FIG. 1 is a drawing for explaining a battery management device according to an embodiment disclosed in this document.

[0040] The battery module (10) may include a plurality of battery cells (11, 12, 13, 14). Referring to FIG. 1, the battery module (10) is illustrated as including four battery cells, but is not limited thereto, and the battery module (10) may be configured to include n (n is a natural number) battery cells.

[0041] The plurality of battery cells (11, 12, 13, 14) may be, but are not limited to, lithium ion (Li-ion) batteries, lithium ion polymer (Li-ion) batteries, nickel cadmium (Ni-Cd) batteries, nickel hydrogen (Ni-H) batteries, etc. In addition, although FIG. 1 illustrates a single battery module (10), a plurality of battery modules may constitute a battery pack (not shown) according to an embodiment.

[0042] The battery module (10) can be connected to a target device (not shown) and supply power to the target device (not shown). To this end, the battery module (10) can be electrically connected to the target device (not shown). Here, the target device (not shown) can include an electrical, electronic, or mechanical device that operates by receiving power from the battery module (10). For example, the target device (not shown) can be, but is not limited to, an electric vehicle (EV), an electric scooter, etc.

[0043] A temperature sensor (10a, 10b) may be attached to at least one battery cell among a plurality of battery cells (11, 12, 13, 14) included in a battery module (10). Referring to FIG. 1, a first temperature sensor (10a) is attached to a first battery cell (11) among a plurality of battery cells (11, 12, 13, 14), and a second temperature sensor (10b) is attached to a third battery cell (13), but the present invention is not limited thereto.

[0044] Temperature sensors (10a, 10b) may be configured to be attached to each of the battery cells (11, 13) and measure the temperature of each of the battery cells (11, 13). The temperature of each of the battery cells (11, 13) measured by the temperature sensors (10a, 10b) may be provided to the battery management device (100), and the battery management device (100) may be configured to control the operation of each of the battery modules (10) and / or the plurality of battery cells (11, 12, 13, 14) included in the battery module (10) based on the temperature of each of the battery cells (11, 13) measured by the temperature sensors (10a, 10b).

[0045] According to one embodiment, the temperature sensor (10a, 10b) may be a thermistor temperature sensor using a thermistor. Here, the thermistor is a type of thermally variable resistor that detects the temperature of a material by utilizing the property of changing resistance according to temperature, and may exhibit a positive temperature coefficient thermistor (PTC) characteristic in which the resistance value increases as the temperature increases, a negative temperature coefficient thermistor (NCT) characteristic in which the resistance value decreases as the temperature increases, and a critical temperature resistor (CTR) characteristic in which the resistance changes in a specific temperature range. In this case, the battery management device (100) may measure the temperature of each battery cell (11, 13) based on the resistance value of the temperature sensor (10a, 10b) attached to each of the battery cells (11, 13).

[0046] The battery management device (100) can manage and / or control the state and / or operation of the battery module (10). The battery management device (100) can manage charging and discharging of the battery module (10), or manage the state and / or operation of each of a plurality of battery cells (11, 12, 13, 14) included in the battery module (10).

[0047] Specifically, the battery management device (100) can monitor voltage, current, temperature, etc. of the battery module (10) and / or each of the plurality of battery cells (11, 12, 13, 14) included in the battery module (10) to control the operation of the battery module (10) and / or each of the plurality of battery cells (11, 12, 13, 14). Based on the monitoring result, the battery management device (100) can calculate parameters indicating the state of the battery module (10) and / or the plurality of battery cells (11, 12, 13, 14), for example, SOC (State of Charge) or SOH (State of Charge).

[0048] According to one embodiment, the battery module (10) may include battery cells (11, 13) to which temperature sensors (10a, 10b) are attached and battery cells (12, 14) to which temperature sensors are not attached. Since the temperature of each of the plurality of battery cells (11, 12, 13, 14) is an important variable that affects the performance of the battery cells (11, 12, 13, 14) and the battery module (10) including them, the battery management device (100) needs to more accurately estimate the temperature of the battery cells (12, 14) to which temperature sensors are not attached.

[0049] The battery management device (100) can monitor the status of each of the plurality of battery cells (11, 12, 13, 14) by measuring and / or estimating the temperature of each of the plurality of battery cells (11, 12, 13, 14). To this end, the battery management device (100) can include a temperature estimation unit (110), a data acquisition unit (120), a temperature compensation unit (130), and a memory (140).

[0050] The temperature estimation unit (110) may be configured to estimate the temperature of each of the plurality of battery cells (11, 12, 13, 14). The temperature estimation unit (110) may estimate the temperature of each of the plurality of battery cells (11, 12, 13, 14) using various internal algorithms.

[0051] According to one embodiment, the temperature estimation unit (110) can estimate the temperature of each of the plurality of battery cells (11, 12, 13, 14) by analyzing EIS (Electrochemical Impedance Spectroscopy) data related to the impedance of each of the plurality of battery cells (11, 12, 13, 14). Here, the process of measuring the EIS data of each of the plurality of battery cells (11, 12, 13, 14) may include an operation of measuring the impedance of each of the plurality of battery cells (11, 12, 13, 14) by applying an AC voltage to the battery module (10).

[0052] According to one embodiment, the temperature estimation unit (110) may obtain EIS data by directly applying voltage and / or current to the battery module (10). In this case, the temperature estimation unit (110) may include various circuits for applying voltage and / or current to the battery module (10) and a processor (not shown) for processing the obtained EIS data.

[0053] According to one embodiment, the temperature estimation unit (110) can indirectly obtain EIS data measured from the battery module (10). In this case, the temperature estimation unit (110) can include various communication circuits and communication modules for communicating with the battery module (10) via wires and / or wirelessly.

[0054] According to one embodiment, the temperature estimation unit (110) can estimate the temperature of each of the plurality of battery cells (11, 12, 13, 14) based on EIS data of each of the plurality of battery cells (11, 12, 13, 14). The internal algorithm for estimating the temperature of each of the plurality of battery cells (11, 12, 13, 14) based on EIS data is not limited to a specific example.

[0055] The data acquisition unit (120) can acquire measurement data related to the measured temperature of each of the plurality of battery cells (11, 12, 13, 14). The data acquisition unit (120) can directly and / or indirectly acquire measurement data related to the temperature of each of the plurality of battery cells (11, 12, 13, 14).

[0056] According to one embodiment, the data acquisition unit (120) may be connected to the temperature sensors (10a, 10b) to acquire measurement data of battery cells (11, 13) to which the temperature sensors (10a, 10b) are attached. Here, the measurement data may include data related to the measured temperature of each of the plurality of battery cells (11, 12, 13, 14). When the temperature sensors (10a, 10b) are configured as thermistor temperature sensors, the data acquisition unit (120) may acquire the resistance value of each of the temperature sensors (10a, 10b) to acquire measurement data related to the measured temperature of each of the battery cells (11, 13). To this end, the temperature sensors (10a, 10b) may be connected to the data acquisition unit (120) through a channel (Channel; Ch), respectively.

[0057] The temperature compensation unit (130) can compensate the temperature of each of the plurality of battery cells (11, 12, 13, 14) estimated by the temperature estimation unit (110) to correspond to the measured temperature of the battery cell (11, 13) according to the measurement data. Here, the temperature compensation unit (130) can compensate the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) based on at least one compensation coefficient.

[0058] According to one embodiment, the temperature compensation unit (130) may compensate the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) based on at least one previously stored compensation factor and / or may calculate and update at least one compensation factor.

[0059] According to one embodiment, the temperature compensation unit (130) may perform operations such as offset compensation, slope compensation, and / or point compensation to compensate for the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13). That is, the temperature compensation unit (130) may compensate for the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) by using at least one of an offset compensation coefficient for offset compensation, a slope coefficient per unit temperature for slope compensation, and a point compensation coefficient for point compensation. The specific details of each compensation process will be described later in the description with respect to FIGS. 3A to 5B.

[0060] According to one embodiment, the temperature compensation unit (130) may perform at least two compensation operations among offset compensation, slope compensation, and point compensation, and / or may perform offset compensation, slope compensation, and point compensation operations simultaneously.

[0061] According to one embodiment, the temperature compensation unit (130) may compensate the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) in each of the plurality of temperature sections to correspond to the measured temperature of the battery cells (11, 13). To this end, the temperature compensation unit (130) may compensate the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) to correspond to the measured temperature of the battery cells (11, 13) by using an offset compensation coefficient, a slope coefficient per unit temperature, and a point compensation coefficient corresponding to each of the plurality of temperature sections.

[0062] According to one embodiment, the temperature estimation unit (110) and the temperature compensation unit (130) may be implemented as a single processor or as separate processors. Here, the processor may execute software to control at least one other component (e.g., hardware or software) of the battery management device (100), or perform operations such as processing and / or calculating various data.

[0063] The memory (140) can store various data required for the operation of the battery management device (100). For example, the memory (140) can store EIS data of each of the plurality of battery cells (11, 12, 13, 14), data related to the temperature of each of the plurality of battery cells (11, 12, 13, 14) estimated based on the EIS data, offset correction coefficients corresponding to each of the plurality of temperature sections, slope coefficients per unit temperature, point correction coefficients, etc. In addition, the memory (140) can store various commands required for the operation of the battery management device (100).

[0064] According to one embodiment, the memory (140) may include a volatile memory device such as a static random access memory (SRAM) or a dynamic random access memory (DRAM), or a non-volatile memory device such as a read only memory (ROM), a programmable ROM (PROM), or a flash memory.

[0065] Referring to FIG. 1, the memory (140) is illustrated as being included in the battery management device (100), but is not limited thereto, and the memory (140) may be located outside the battery management device (100).

[0066] FIG. 2 is a diagram for explaining temperature data according to an embodiment disclosed in this document.

[0067] Referring to FIG. 2, the relationship between the estimated temperature and the measured temperature for the battery cell (11) is illustrated, taking as an example a battery cell (11) having a temperature sensor (10a) attached among a plurality of battery cells (11, 12, 13, 14, see FIG. 1).

[0068] According to one embodiment, the vertical axis shown on the left side of the graph illustrated in FIG. 2 represents temperature (℃), and the vertical axis shown on the right side of the graph represents the size of the absolute value of the error.

[0069] Each graph illustrated in FIG. 2 represents the measured temperature and estimated temperature for the battery cell (11). The measured temperature and estimated temperature of the battery cell (11) corresponding to the same horizontal axis coordinate can constitute one data set. For example, the measured temperature and estimated temperature of the battery cell (11) corresponding to the coordinate of a based on the horizontal axis can correspond to approximately 52 degrees and 50 degrees. This can indicate that when the measured temperature of the battery cell (11) is 52 degrees, the temperature of the battery cell (11) estimated based on the EIS data acquired through EIS analysis of the battery cell (11) is 50 degrees.

[0070] According to one embodiment, whenever the temperature of the battery cell (11) is measured through the temperature sensor (10a) attached to the battery cell (11), an error occurs between the temperature of the battery cell (11) estimated based on EIS data obtained through EIS analysis of the battery cell (11). Referring to a graph showing the absolute value of the error, the absolute value of the error tends to increase when the measured temperature of the battery cell (11) is below zero or exceeds 50 degrees Celsius. In addition, the absolute value of the error tends to be maintained at a constant level in a specific temperature range (for example, a range where the measured temperature of the battery cell (11) is between about 5 degrees Celsius and 7 degrees Celsius). That is, since there is a different tendency between the measured temperature of the battery cell (11) and the temperature of the battery cell (11) estimated based on the EIS data obtained through EIS analysis of the battery cell (11) for each section of the measured temperature of the battery cell (11), the correction coefficient for correcting the estimated temperature of the battery cell (11) to correspond to the measured temperature in each of the plurality of temperature sections may also be different.

[0071] According to one embodiment, the temperature compensation unit (130, see FIG. 1) may generate a compensation coefficient corresponding to each of a plurality of temperature sections (1, 2, 3, 4), or may use the compensation coefficient to compensate the estimated temperature of the battery cell (11) to correspond to the measured temperature of the battery cell (11).

[0072] According to one embodiment, the temperature compensation unit (130) may compensate for the temperature of the battery estimated through EIS analysis of each of the other battery cells, for example, the battery cells (12, 13, 14) described with reference to FIG. 1, by using at least one compensation coefficient generated based on the error between the estimated temperature and the measured temperature of the battery cell (11).

[0073] The temperature compensation unit (130) can compensate the estimated temperature of each of the plurality of battery cells (11, 12, 13, 14) based on the start temperature and end temperature of each of the plurality of temperature sections (1, 2, 3, 4) and at least one compensation coefficient corresponding to each of the plurality of temperature sections (1, 2, 3, 4).

[0074] For example, referring to FIG. 2, the estimated temperature of the first battery cell (11) at the point where the third section (3) starts may be 10 degrees, and the estimated temperature of the first battery cell (11) at the point where the third section (3) ends may be 14 degrees. Accordingly, if the temperature compensation unit (130) estimates the temperature of the third battery cell (13) based on EIS data obtained through EIS analysis of a battery cell other than the first battery cell (11), for example, the third battery cell (13), and the result is 10 to 14 degrees, the temperature compensation unit (130) may compensate the estimated temperature of the third battery cell (13) to correspond to the measured temperature of the third battery cell (13) using at least one compensation coefficient generated in the third section (3) based on the first battery cell (11).

[0075] Referring to FIG. 2, only four sections (1, 2, 3, 4) are shown, but this is not limited thereto, and the temperature of the battery cell (11) can be continuously divided to have a different number and different temperature range.

[0076] FIGS. 3A and 3B are drawings for explaining offset correction according to an embodiment disclosed in this document.

[0077] First, referring to FIG. 3A, a graph is shown related to the estimated temperature of the battery, the measured temperature, the absolute value of the error, the temperature of the battery after performing offset correction using the first offset correction coefficient (C1), and the temperature of the battery after performing offset correction using the second offset correction coefficient (C2). The graph shown in FIG. 3A may correspond to any one of the multiple temperature ranges described with reference to FIG. 2, and does not correspond to a specific temperature range.

[0078] According to one embodiment, the graph illustrated in FIG. 3a may be a graph related to the temperature of a battery cell (11). The temperature compensation unit (130, see FIG. 1) may calculate a first offset compensation coefficient (C1) and / or a second offset compensation coefficient (C2) based on the graph illustrated in FIG. 3a.

[0079] Offset correction may be a correction that adds or subtracts the same offset correction factor to each estimated temperature of the battery cell (11). In one embodiment, the offset correction factor may be determined based on the absolute value of the error between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11).

[0080] Referring to FIG. 3b, data related to the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) illustrated in FIG. 3a are illustrated. According to one embodiment, the temperatures of the battery cell (11) obtained through the temperature sensor (10a) attached to the battery cell (11) may be 5 degrees, 5.5 degrees, 5.8 degrees, 7 degrees, 7.5 degrees, and 10 degrees, respectively, and at the same time, the temperatures of the battery cell (11) estimated based on the EIS data obtained through EIS analysis for the battery cell (11) may be 4.8 degrees, 5.3 degrees, 5.4 degrees, 7.2 degrees, 7.4 degrees, and 8 degrees, respectively. However, although only six data are illustrated in FIG. 3b, the present invention is not limited thereto, and may further include data related to the estimated temperature and the measured temperature of the battery cell (11) corresponding to various temperature intervals.

[0081] According to one embodiment, the error between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) may be defined as a value obtained by subtracting the estimated temperature of the battery cell (11) from the measured temperature of the battery cell (11). That is, the errors between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) may be 0.2 degrees, 0.2 degrees, 0.4 degrees, -0.2 degrees, 0.1 degrees, and 2 degrees, respectively. Accordingly, the absolute values ​​of the errors between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) may be 0.2 degrees, 0.2 degrees, 0.4 degrees, 0.2 degrees, 0.1 degrees, and 2 degrees, respectively.

[0082] According to one embodiment, the offset correction factor (C1) may correspond to the median value of the absolute values ​​of the errors of the battery cells (11). That is, the temperature compensation unit (130) may identify the maximum and minimum values ​​among the absolute values ​​of the errors of the battery cells (11), and determine the median value of the identified maximum and minimum values ​​as the offset correction factor (C1). In this case, the offset correction factor (C1) may be set to 1.05, which is an intermediate value between 2, which is the maximum value of the absolute value of the errors, and 0.1, which is the minimum value of the absolute value of the errors.

[0083] In one embodiment, the offset correction factor (C2) may correspond to the average value of the absolute values ​​of the errors of the battery cells (11). That is, the temperature correction unit (130) may calculate the sum of each absolute value of the errors of the battery cells (11) (0.2+0.2+0.4+0.2+0.1+2) and calculate the average thereof to determine the offset correction factor (C2). In this case, the offset correction factor (C2) may be 0.5, which is the average value.

[0084] The error correction unit (130) can perform offset correction by adding or subtracting the calculated offset correction coefficient (C1 or C2) to the estimated temperature of the battery cell (11). Here, since the estimated temperature of the battery cell (11) is lower than the measured temperature of the battery cell (11), the error correction unit (130) can perform offset correction by adding the offset correction coefficient (C1) to the estimated temperature of the battery cell (11). This is because the offset correction coefficient (C1 or C2) is calculated based on the absolute value of the error of the battery cell (11), and therefore, the offset correction coefficient (C1 or C2) always has a positive value.

[0085] According to one embodiment, the error correction unit (130) may correct an error in the estimated temperature of the battery cell (11) by adding an offset correction coefficient (C1) to the estimated temperature of the battery cell (11). Accordingly, the temperatures of the battery cell (11) subjected to the offset correction (C1) may be 5.85 degrees, 6.35 degrees, 6.45 degrees, 8.25 degrees, 8.45 degrees, and 9.05 degrees, respectively.

[0086] According to one embodiment, the error correction unit (130) may correct an error in the estimated temperature of the battery cell (11) by adding an offset correction coefficient (C2) to the estimated temperature of the battery cell (11). Accordingly, the temperatures of the battery cell (11) subjected to the offset correction (C2) may be 5.3 degrees, 5.8 degrees, 5.9 degrees, 7.7 degrees, 7.9 degrees, and 8.5 degrees, respectively.

[0087] The error correction unit (130) can determine whether to perform offset correction using which offset correction coefficient in the corresponding section based on the temperature of the battery cell (11) corrected based on each offset correction coefficient (C1 or C2) and the measured temperature of the battery cell (11). For example, the error correction unit (130) can determine to perform offset correction using an offset correction coefficient with a small error by calculating the root mean square error (RMSE) or mean absolute error based on the error between the temperature of the battery cell (11) corrected based on each offset correction coefficient (C1 or C2) and the measured temperature of the battery cell (11), but is not limited to these examples.

[0088] The error correction unit (130) can store the offset correction coefficients (C1 and C2), the start temperature and the end temperature of the corresponding temperature section in the memory (140, see FIG. 1). When the error correction unit (130) estimates the temperature of the battery cell (12, 13, 14) based on EIS data obtained through EIS analysis of the battery cell (11) and other battery cells (12, 13, 14) based on the start temperature, the end temperature, and the offset correction coefficients (C1 and C2) of the temperature section, the error correction unit (130) can correct the estimated temperature of the battery cell (12, 13, 14) using the offset correction coefficient (C1 or C2) generated in the process of correcting the temperature of the battery cell (11).

[0089] According to one embodiment, when the temperature of the second battery cell (12) estimated based on EIS data obtained through EIS analysis of the second battery cell (12) to which the temperature sensor is not attached is 8 degrees, the temperature compensation unit (130) may reflect the offset compensation coefficient generated in the process of compensating the temperature of the first battery cell (11) to the estimated temperature of the second battery cell (12). That is, when the estimated temperature of the second battery cell (12) is 8 degrees, the temperature compensation unit (130) may perform offset compensation to correct the estimated temperature of the second battery cell (12) to 9.05 degrees or 8.5 degrees.

[0090] FIGS. 4A and 4B are drawings for explaining slope correction according to an embodiment disclosed in this document.

[0091] First, referring to Fig. 4a, a graph (a) related to the estimated temperature of the battery, the measured temperature, and the temperature of the battery after performing slope correction is shown on the left. The graph (a) shown in Fig. 4a may correspond to any one of the multiple temperature ranges described with reference to Fig. 2, and does not correspond to a specific temperature range. In addition, for convenience of explanation, it is assumed that the temperature range corresponding to the graph (a) shown in Fig. 4a is the estimated temperature of the battery cell (11) between 43 degrees and 50 degrees.

[0092] Additionally, graph (b) illustrated in Fig. 4a is a graph representing the error of graph (a) illustrated on the left. Slope correction may be a correction that reflects the slope of a straight line (a) having an average rate of change between the errors of graph (b) illustrated on the right.

[0093] According to one embodiment, the graph illustrated in FIG. 4A may be a graph related to the temperature of a battery cell (11). A temperature compensation unit (130, see FIG. 1) may calculate a slope compensation coefficient based on the graph illustrated in FIG. 4A, and generate a formula for compensating the estimated temperature of the battery cell (11) based on the calculated slope compensation coefficient.

[0094] Slope correction may be a correction that substitutes the estimated temperature of the battery cell (11) into a generated formula so that the estimated temperature of the battery cell (11) corresponds to the measured temperature of the battery cell (11). According to one embodiment, the formula generated based on the slope correction coefficient may be in the form of a linear function (y=ax+b, where a is a non-zero real number), but is not limited to this example.

[0095] According to one embodiment, the formula for correcting the estimated temperature of the battery cell (11) may be a linear function whose slope is a slope correction coefficient. Referring to FIG. 4B, data related to the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) shown in FIG. 4A are shown. According to one embodiment, the temperature of the battery cell (11) obtained through the temperature sensor (10a) attached to the battery cell (11) may be 45 degrees, 51 degrees, 54 degrees, and 55 degrees, respectively, and at the same time, the temperature of the battery cell (11) estimated based on the EIS data obtained through EIS analysis for the battery cell (11) may be 43 degrees, 48 ​​degrees, 49 degrees, and 50 degrees, respectively. Although only four data are shown in FIG. 4B, the present invention is not limited thereto, and may further include data related to the estimated temperature and the measured temperature of the battery cell (11) corresponding to more diverse temperature intervals.

[0096] According to one embodiment, the error between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) may be defined as the value obtained by subtracting the estimated temperature of the battery cell (11) from the measured temperature of the battery cell (11). That is, the error between the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) may be 2 degrees, 3 degrees, 5 degrees, and 5 degrees, respectively.

[0097] According to one embodiment, the slope correction factor may be determined based on the error between the measured temperature and the estimated temperature of the battery cell (11) at the start and end points of each of the temperature sections. For example, as shown in FIG. 4B, when the temperature section set based on the estimated temperature of the battery cell (11) is between 43 degrees and 50 degrees, the slope correction factor may be determined based on the error when the estimated temperature of the battery cell (11) is 43 degrees and the error when the estimated temperature of the battery cell (11) is 50 degrees.

[0098] According to one embodiment, the slope correction factor may correspond to the average rate of change of the error between the measured temperature and the estimated temperature of the battery cell (11) at each of the start point and the end point in the temperature section. Since the error at the point where the estimated temperature of the battery cell (11) is 43 degrees is 2 degrees, and the error at the point where the estimated temperature of the battery cell (11) is 5 degrees, the slope correction factor may be 0.429, which is a value obtained by dividing the rate of change between the errors, 3 degrees (5 degrees - 2 degrees), by the length of the temperature section (50 degrees - 43 degrees).

[0099] According to one embodiment, the estimated temperature of the battery cell (11) at the starting point of each of the plurality of temperature sections may be corrected to correspond to the measured temperature of the battery cell (11). For example, the temperature of 43 degrees, which is the starting point of a temperature section (between 43 degrees and 50 degrees) distinguished based on the estimated temperature of the battery cell (11), may be corrected to become 45 degrees. That is, the formula generated based on the slope correction coefficient may pass through a point corresponding to the measured temperature of the battery cell (11) at the starting point of each of the plurality of temperature sections.

[0100] The formula generated based on the above is as follows.

[0101] Y = (X+2) + 0.429*(X-43) (where Y corresponds to the temperature at which slope correction is performed on the estimated temperature of the battery cell (11), X corresponds to the estimated temperature of the battery cell (11), and X is a real number between 43 and 50.)

[0102] The temperature compensation unit (130, see FIG. 1) can compensate the estimated temperature of the battery cell (11) to correspond to the measured temperature of the battery cell (11) by substituting each of the estimated temperatures of the battery cell (11) into the above formula. That is, the temperatures of the battery cell (11) for which slope compensation is performed by substituting the estimated temperatures of the battery cell (11) of 43 degrees, 48 ​​degrees, 49 degrees, and 50 degrees into the mathematical formula can be 45 degrees, 52.145 degrees, 53.574 degrees, and 55.003 degrees, respectively.

[0103] The error correction unit (130) can store in the memory (140, see FIG. 1) the error of the battery cell (11) at the start point and the end point of each of the plurality of temperature sections, the slope correction coefficient, and the formula generated based on the slope correction coefficient. When the error correction unit (130) estimates the temperature of the battery cell (12, 13, 14) based on EIS data obtained through EIS analysis of the battery cell (11) and other battery cells (12, 13, 14) based on the formula in each of the plurality of temperature sections, the estimated temperature of the battery cell (12, 13, 14) can be corrected using the formula generated in the process of correcting the temperature of the battery cell (11).

[0104] According to one embodiment, when the temperature of the second battery cell (12) estimated based on EIS data obtained through EIS analysis of the second battery cell (12) to which the temperature sensor is not attached is 45 degrees, the temperature compensation unit (130) can compensate for the temperature of the second battery cell (12) by substituting the estimated temperature of the second battery cell (12) into the formula generated in the process of compensating the temperature of the first battery cell (11). That is, when the estimated temperature of the second battery cell (12) is 45 degrees, the temperature compensation unit (130) can compensate for the estimated temperature of the second battery cell (12) to 47.858 degrees by performing slope compensation.

[0105] FIGS. 5A and 5B are drawings for explaining point correction according to an embodiment disclosed in this document.

[0106] First, referring to FIG. 5a, a graph is shown relating to the battery's estimated temperature, measured temperature, point correction coefficient, and temperature of the battery after point correction using the point correction coefficient. The graph shown in FIG. 5a may correspond to any one of the multiple temperature ranges described with reference to FIG. 2, and does not correspond to a specific temperature range.

[0107] According to one embodiment, referring to the graph showing the absolute value of the error as illustrated in FIG. 2, when the measured temperature of the battery cell (11, see FIG. 1) is below zero or exceeds 50 degrees Celsius, the absolute value of the error tends to increase. That is, when the temperature of the battery cell (11) enters a specific section, there are cases where the absolute value of the error is not constant. In such a section, when the offset correction described with reference to FIGS. 3A and 3B is performed, it is difficult to ensure accuracy when correcting the error between the estimated temperature and the measured temperature of the battery cell (11). Therefore, the error correction unit (130) may perform point correction by adding a pre-stored point correction coefficient to the estimated temperature of the battery cell (11) when the estimated temperature of the battery cell (11) reaches a specific temperature point.

[0108] Referring to FIG. 5b, data related to the estimated temperature of the battery cell (11) and the measured temperature of the battery cell (11) illustrated in FIG. 5a are illustrated. According to one embodiment, the temperature of the battery cell (11) obtained through the temperature sensor (10a) attached to the battery cell (11) may be 53 degrees, 54 degrees, and 56 degrees, respectively, and at the same time, the temperature of the battery cell (11) estimated based on EIS data obtained through EIS analysis for the battery cell (11) may be 50 degrees, 50.5 degrees, and 51 degrees, respectively.

[0109] According to one embodiment, the temperature compensation unit (130) may perform point compensation based on the estimated temperature of the battery cell (11) stored in advance and the point compensation coefficient corresponding thereto. For example, when the point compensation coefficient is 2 when the estimated temperature of the battery cell (11) is 50 degrees, the temperature compensation unit (130) may perform point compensation by adding the point compensation coefficient to the estimated temperature. This point compensation coefficient may represent one value corresponding to each specific temperature value. Similarly, the temperature compensation unit (130) may perform point compensation by adding the point compensation coefficient to each estimated temperature of the battery cell (11), and the results may correspond to 52 degrees, 53.5 degrees, and 55 degrees.

[0110] In order to increase the energy density within the battery pack, it is difficult to position a temperature sensor in each of the battery cells (11, 12, 13, 14), so the temperature of each of the battery cells (11, 12, 13, 14) must be estimated. However, as described above, there is an error between the temperature estimated based on EIS data obtained through EIS analysis of multiple battery cells (11, 12, 13, 14) and the actual measured temperature of the battery cells (11, 12, 13, 14). Therefore, there is a need to compensate the estimated temperature of the battery cells (11, 12, 13, 14) to estimate the temperature of the battery cells (11, 12, 13, 14) more accurately. Currently, the algorithm for estimating the temperature of battery cells (11, 12, 13, 14) through EIS analysis has a possibility of changing the error between the measured temperatures of battery cells (11, 12, 13, 14) due to various variables (e.g., SOC, humidity, pressure, degree of degradation, etc.), so it is inefficient to compensate for the temperature of battery cells (11, 12, 13, 14) using a fixed compensation factor. Accordingly, the battery management device (100, see FIG. 1) according to an embodiment disclosed in the present document can calculate and update various compensation factors when performing EIS analysis of battery cells (11, 12, 13, 14), and can set more flexible compensation factors, thereby improving the accuracy of temperature estimation.

[0111] FIG. 6 is a flowchart illustrating the operation of a battery management device according to an embodiment disclosed in this document.

[0112] In step S101, the battery management device (100, see FIG. 1) can estimate the temperature of each of the battery cells (11, 12, 13, 14) based on EIS data related to the impedance of the battery cells (11, 12, 13, 14). Here, the internal algorithm for estimating the temperature of each of the plurality of battery cells (11, 12, 13, 14) based on the EIS data is not limited to a specific example.

[0113] In step S102, the battery management device (100) can obtain measurement data related to the measured temperature of the battery cell (11, 13).

[0114] According to one embodiment, a temperature sensor (10a, 10b) may be attached to at least one battery cell (11, 13) among the battery cells (11, 12, 13, 14), respectively. When the temperature sensors (10a, 10b) are configured as thermistor temperature sensors, the battery management device (100) may obtain the resistance values ​​of each of the temperature sensors (10a, 10b) to obtain measurement data related to the measured temperature of each of the battery cells (11, 13). To this end, the temperature sensors (10a, 10b) may be connected to the battery management device (100) via a channel (Channel; Ch).

[0115] In step S103, the battery management device (100) can correct the estimated temperature of the battery cell (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) using at least one correction coefficient generated based on the error between the measured temperature and the estimated temperature of the battery cell (11, 13).

[0116] According to one embodiment, the step of correcting the estimated temperature of the battery cell (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) may include the step of dividing data related to the estimated temperature of the battery cell (11, 12, 13, 14) into a plurality of temperature sections and the step of correcting the estimated temperature of the battery cell (11, 12, 13, 14) to correspond to the measured temperature of the battery cell (11, 13) using a correction coefficient corresponding to each of the plurality of temperature sections.

[0117] According to one embodiment, the battery management device (100) may perform offset correction by adding or subtracting an offset correction coefficient, which is one of at least one correction coefficient corresponding to each of a plurality of temperature sections, to the estimated temperature of the battery cells (11, 12, 13, 14) in each of the plurality of temperature sections. Here, the offset correction coefficient may be determined based on an absolute value of an error between the measured temperature and the estimated temperature of the battery cells (11, 12, 13, 14) in each of the plurality of temperature sections, and may correspond to, for example, an average value or a median value of the absolute value of the error, but is not limited thereto.

[0118] According to one embodiment, the battery management device (100) may perform slope correction on each of the estimated temperatures of the battery cells (11, 12, 13, 14) in each of the plurality of temperature sections using a formula generated based on a slope correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature sections. Here, the slope correction coefficient may be determined based on an error between the measured temperature and the estimated temperature of the battery cell (11) at a start point and an end point of each of the plurality of temperature sections, and may correspond to an average rate of change of the error between the temperatures at each of the start point and the end point.

[0119] According to one embodiment, the battery management device (100) can calculate a slope correction coefficient by multiplying the slope coefficient per unit temperature by the error between the measured temperature and the estimated temperature of the battery cell, respectively.

[0120] In the above, all components constituting the embodiments have been described as being combined or operating in combination as one. However, this is not necessarily limited to such embodiments, and within the scope of the purpose, all components may be selectively combined and operated in one or more combinations. Furthermore, terms such as "include," "comprise," or "have" described above, unless specifically stated to the contrary, imply that the corresponding component may be inherent, and therefore should be interpreted to include other components rather than excluding other components.

[0121] The above description is merely an example of the technical idea disclosed in this document, and those skilled in the art to which the embodiments disclosed in this document pertain may make various modifications and variations without departing from the essential characteristics of the embodiments disclosed in this document.

[0122] Accordingly, the embodiments disclosed in this document are intended to illustrate, rather than limit, the technical concepts disclosed in this document, and the scope of the technical concepts disclosed in this document is not limited by these embodiments. The scope of protection of the technical concepts disclosed in this document should be interpreted by the claims below, and all technical concepts within the equivalent scope should be interpreted as being included within the scope of the rights of this document.

[0123] [Explanation of symbols]

[0124] 10: Battery module 11, 12, 13, 14: Battery cell

[0125] 10a, 10b: Temperature sensor 100: Battery management unit

[0126] 110: Temperature estimation unit 120: Data acquisition unit

[0127] 130: Temperature compensation unit 140: Memory

Claims

1. A temperature estimation unit that estimates the temperature of the battery based on EIS data related to the impedance of the battery; A data acquisition unit for acquiring measurement data related to the measured temperature of the above battery; and A battery management device comprising a temperature compensation unit that compensates the estimated temperature of the battery to correspond to the measured temperature of the battery based on at least one compensation coefficient generated based on an error between the measured temperature of the battery and the estimated temperature of the battery according to the measurement data.

2. In the first paragraph, the temperature compensation unit, A battery management device that corrects the estimated temperature of the battery to correspond to the measured temperature of the battery by using a correction coefficient corresponding to each of a plurality of temperature ranges.

3. In the second paragraph, the temperature compensation unit, A battery management device that performs offset correction by adding or subtracting an offset correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature sections, to the estimated temperature of the battery in each of the plurality of temperature sections, thereby correcting the estimated temperature of the battery to correspond to the measured temperature of the battery.

4. In the third paragraph, the offset correction coefficient is A battery management device determined based on the absolute value of the error between the estimated temperature of the battery and the measured temperature of the battery in each of the plurality of temperature sections.

5. In the fourth paragraph, the offset correction coefficient is A battery management device corresponding to the average value of the absolute values ​​of errors in each of the above multiple temperature ranges.

6. In the fourth paragraph, the offset correction coefficient is A battery management device corresponding to the median value of the absolute values ​​of the errors in each of the above plurality of temperature ranges.

7. In the second paragraph, the temperature compensation unit, A battery management device that corrects the estimated temperature of the battery to correspond to the measured temperature of the battery by substituting the estimated temperature of the battery into a formula generated based on a slope correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature sections.

8. In the 7th paragraph, the formula is, A battery management device having a linear function whose slope is an average rate of change between the error between the measured temperature of the battery and the estimated temperature of the battery at each of the start and end points of each of the plurality of temperature intervals.

9. In paragraph 8, A battery management device wherein the estimated temperature of the battery at the starting point of each of the plurality of temperature sections is corrected to correspond to the measured temperature of the battery.

10. In the first paragraph, the temperature compensation unit, A battery management device that corrects the estimated temperature of the battery to correspond to the measured temperature of the battery by using a point correction coefficient, which is one of the at least one correction coefficient, when the estimated temperature of the battery corresponds to a preset temperature.

11. A step of estimating the temperature of the battery based on EIS data related to the impedance of the battery; A step of acquiring measurement data related to the measured temperature of the above battery; and A method of operating a battery management device, comprising: a step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery based on at least one correction coefficient generated based on an error between the measured temperature of the battery and the estimated temperature of the battery according to the measurement data; 12. In the 11th paragraph, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery is: A step of dividing data related to the estimated temperature of the battery into a plurality of temperature sections; and A method for operating a battery management device, comprising: a step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery using a correction coefficient corresponding to each of the plurality of temperature sections; 13. In the 12th paragraph, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery is, A step of performing offset correction by adding or subtracting an offset correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature sections, to the estimated temperature of the battery in each of the plurality of temperature sections; The above offset correction factor is, An operating method of a battery management device, wherein the operating method is determined based on the absolute value of the error between the estimated temperature of the battery and the measured temperature of the battery in each of the plurality of temperature sections.

14. In the 13th paragraph, the offset correction coefficient is An operating method of a battery management device corresponding to an average value or a median value of the absolute values ​​of errors in each of the above plurality of temperature sections.

15. In the 12th paragraph, the step of correcting the estimated temperature of the battery to correspond to the measured temperature of the battery is, A step of generating a formula based on a slope correction coefficient, which is at least one correction coefficient corresponding to each of the plurality of temperature ranges; and A method for operating a battery management device, comprising: a step of substituting the estimated temperature of the battery into the above formula and correcting the estimated temperature of the battery to correspond to the measured temperature of the battery.

16. In paragraph 15, The above formula corresponds to a linear function whose slope is the average rate of change between the error between the measured temperature of the battery and the estimated temperature of the battery at each of the start and end points of each of the plurality of temperature intervals, A method of operating a battery management device, wherein the estimated temperature of the battery at the starting point of each of the plurality of temperature intervals is corrected to correspond to the measured temperature of the battery.

Images