Battery management system and battery management method

Abstract

A battery management method according to the present invention comprises the steps of: generating charging monitoring information of a battery for a charging period; generating discharging monitoring information of the battery for a discharging period; determining, on the basis of the charging monitoring information and the discharging monitoring information, charging energy of the battery for a first period within the charging period and discharging energy of the battery for a second period within the discharging period; and determining, on the basis of the charging energy and the discharging energy, a first degradation factor indicating a level of increase of internal resistance of the battery due to degradation compared to the beginning of life.

Description

Battery Management System and Battery Management Method

[0001] The present invention relates to a technology for diagnosing battery degradation based on battery charge / discharge monitoring information.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2025-0037492 filed on March 24, 2025, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003] Currently commercialized batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium batteries. Among these, lithium batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0004] Recently, as the demand for electric vehicles has increased explosively worldwide, the need for technology capable of precisely diagnosing the degradation level of electric vehicle batteries (hereinafter referred to as 'batteries') is also rising.

[0005] Battery degradation levels can be broadly classified into capacity degradation and resistance degradation. Capacity degradation can be diagnosed relatively simply by estimating the battery's full charge capacity based on battery information collected during the charging and / or discharging of the electric vehicle.

[0006] Meanwhile, resistance degradation is typically diagnosed based on the ratio of the change in voltage to the battery current flowing during a minute time (e.g., 0.001 seconds) during charging or discharging, according to Ohm's law. The internal resistance and polarization voltage of a battery have a non-linear relationship with each other, and not only are the polarity and magnitude of the polarization voltage dependent on the polarity of the battery current, but the battery voltage is also significantly affected by the battery temperature as well as the battery current. Therefore, the accuracy of the diagnosis results for resistance degradation based on battery information over a minute time can often be significantly reduced.

[0007] The present invention aims to provide a battery management system and a battery management method for diagnosing the level of increase in the internal resistance of a battery based on monitoring information for both the charging period and the discharging period.

[0008] Other objects and advantages of the present invention may be understood from the following description and will become more clearly apparent from the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0009] A battery management method according to one aspect of the present invention comprises: generating charging monitoring information of a battery for a charging period; generating discharge monitoring information of the battery for a discharge period; determining, based on the charging monitoring information and the discharge monitoring information, a charging energy of the battery for a first period within the charging period and a discharge energy of the battery for a second period within the discharge period, if the increase in the remaining capacity of the battery during the charging period is greater than or equal to a threshold capacity and the decrease in the remaining capacity of the battery during the discharge period is greater than or equal to the threshold capacity; and determining a first degradation factor indicating the level of increase in internal resistance of the battery due to degradation compared to the initial lifespan, based on the charging energy and the discharge energy.

[0010] The charging monitoring information may include voltage time series data and current time series data of the battery for the first period. The discharging monitoring information may include voltage time series data and current time series data of the battery for the second period.

[0011] The first period may be from a first point in time of the charging period to the end point of the charging period. The current integrated value during the first period may be equal to the critical capacity.

[0012] The second period may be from the start of the discharge period to a second point in time within the discharge period. The current integrated value during the second period may be equal to the critical capacity.

[0013] The step of determining the first degradation factor of the battery may include: determining a first diagnostic value representing the ratio of the charge energy to the discharge energy; determining a second diagnostic value representing the ratio of the difference between the first diagnostic value and the reference value with respect to a predetermined reference value; adjusting the second diagnostic value based on a predetermined scaling constant to determine a third diagnostic value; and applying data smoothing logic to the history data of the third diagnostic value to determine the first degradation factor.

[0014] The battery management method described above may further include the step of determining a correction factor for removing a noise component included in the first degradation factor based on the charge monitoring information and the discharge monitoring information, wherein the noise component included in the first degradation factor is due to the difference between each of the plurality of actual charge conditions during the first period and the standard charge condition of each of the plurality of actual discharge conditions during the second period; and the step of determining a second degradation factor of the battery by correcting the first degradation factor based on the correction factor.

[0015] The charging monitoring information may include voltage time series data, current time series data, temperature time series data, and SOC time series data of the battery for the first period. The discharging monitoring information may include voltage time series data, current time series data, temperature time series data, and SOC time series data of the battery for the second period.

[0016] The step of determining the correction factor may include inputting a real charge / discharge condition data set, including the plurality of actual charge conditions and the plurality of actual discharge conditions, into a factor correction model to determine the correction factor. The factor correction model may be a machine learning model that has been pre-trained by a plurality of training data sets.

[0017] The step of determining the correction factor may include: a step of determining a plurality of charge correction values ​​by individually comparing the plurality of actual charge conditions with the standard charge conditions; a step of determining a plurality of discharge correction values ​​by individually comparing the plurality of actual discharge conditions with the standard discharge conditions; and a step of determining the correction factor based on the plurality of charge correction values ​​and the plurality of discharge correction values.

[0018] A battery management system according to another aspect of the present invention comprises: a sensing unit for measuring at least one of the voltage, current, and temperature of a battery; and a processor configured to generate charging monitoring information of the battery for a charging period and discharging monitoring information of the battery for a discharging period based on sensing data from the sensing unit. The processor is configured to determine the charging energy of the battery for a first period within the charging period and the discharging energy of the battery for a second period within the discharging period based on the charging monitoring information and the discharging monitoring information if the increase in the remaining capacity of the battery during the charging period is greater than or equal to a threshold capacity and the decrease in the remaining capacity of the battery during the discharging period is greater than or equal to the threshold capacity. The processor is configured to determine a first degradation factor representing the level of increase in the internal resistance of the battery due to degradation compared to the initial lifespan based on the charging energy and the discharging energy.

[0019] The processor may be configured to determine a first diagnostic value representing the ratio of the charge energy to the discharge energy, determine a second diagnostic value representing the ratio of the difference between the first diagnostic value and the reference value to a predetermined reference value, determine a third diagnostic value by multiplying the second diagnostic value by a predetermined scaling constant, and determine the first degradation factor by applying data smoothing logic to the history data of the third diagnostic value.

[0020] The processor may be configured to determine a correction factor for removing noise components included in the first degradation factor based on the charge monitoring information and the discharge monitoring information. The noise components included in the first degradation factor may be due to differences from a predetermined standard charge condition for each of a plurality of actual charge conditions during the first period and differences from a predetermined standard discharge condition for each of a plurality of actual discharge conditions during the second period. The processor may be configured to determine a second degradation factor of the battery by correcting the first degradation factor based on the correction factor.

[0021] A battery pack according to another aspect of the present invention includes the battery management system.

[0022] An electric vehicle according to another aspect of the present invention includes the battery pack.

[0023] A computer-readable medium according to another aspect of the present invention records a program for executing the battery management method on a computer.

[0024] According to at least one of the embodiments of the present invention, the level of increase in the internal resistance of a battery can be diagnosed based on monitoring information for both the charging period and the discharging period. In this case, the amount of change in the remaining capacity of the battery over each of the charging period and the discharging period may be greater than or equal to the critical capacity. That is, since the monitoring information is acquired over a sufficiently long period of time, the accuracy of the diagnosis result regarding resistance degradation can be improved.

[0025] In addition, according to at least one of the embodiments of the present invention, the diagnostic result regarding the resistance degradation of the battery (the 'first degradation factor' to be described later) can be corrected based on the difference between the actual charge / discharge conditions and the standard charge / discharge conditions during the charge period and the discharge period. Therefore, even in situations where the actual charge / discharge conditions during the charge period and the discharge period are not controlled to the standard charge / discharge conditions, the decrease in accuracy of the diagnostic result regarding the resistance degradation of the battery can be suppressed.

[0026] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims.

[0027] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0028] FIG. 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention in an exemplary manner.

[0029] Figure 2 is a graph that exemplarily shows the change in the remaining capacity of a battery over time.

[0030] Figure 3 is an example of a data table referenced to explain the process of determining the first degradation factor.

[0031] FIG. 4 is a flowchart schematically illustrating a battery management method according to a first embodiment of the present invention.

[0032] FIG. 5 is a drawing referenced to explain a factor correction model provided for correcting a first degradation factor.

[0033] FIG. 6 is a flowchart schematically illustrating a battery management method according to a second embodiment of the present invention.

[0034] Figure 7 shows the SOH according to the driving distance of an electric vehicle. C and SOH R This is a drawing referenced to exemplarily explain the pattern of change.

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0036] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0037] Terms including ordinal numbers, such as first, second, etc., are used for the purpose of distinguishing one of the various components from the rest, and are not used to limit the components by such terms.

[0038] Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "<unit>" as used in the specification refer to a unit that performs at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

[0039] Additionally, throughout the specification, when it is said that a part is "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other components in between.

[0040] FIG. 1 is a diagram illustrating the configuration of an electric vehicle according to the present invention in an exemplary manner.

[0041] Referring to FIG. 1, an electric vehicle (EV) includes a battery pack (10), a vehicle controller (2), an inverter (30), and a motor (40).

[0042] The battery pack (10) includes a battery (B), a relay (R), and a battery management system (100).

[0043] The battery (B) includes at least one battery cell. Each battery cell may be, for example, a lithium-ion cell. Of course, the type of battery cell is not limited to a lithium-ion cell, and is not specifically limited as long as it is capable of repeated charging and discharging. Each battery cell included in the battery (B) is electrically connected in series or parallel with other battery cells.

[0044] A relay (R) is installed in a current path for charging and discharging the battery (B). The control terminal of the relay (R) may be provided to be electrically connectable to a battery management system (100). The relay (R) may be controlled to be turned on or off according to a switching signal (SS) output by the battery management system (100) and / or the vehicle controller (2).

[0045] It includes a vehicle controller (2), a battery pack (10), a relay (20), an inverter (30), and an electric motor (40). The charging and discharging terminals (P+, P-) of the battery pack (10) can be electrically connected to a charger (3) via a charging cable or the like. The charger (3) may be included in the electric vehicle (1) or provided in a charging station.

[0046] A vehicle controller (2) (e.g., ECU: Electronic Control Unit) is configured to transmit a key-on signal to a battery management system (100) in response to a start button (not shown) provided in an electric vehicle (EV) being switched to the ON position by a user. The vehicle controller (2) is configured to transmit a key-off signal to a battery management system (100) in response to a start button being switched to the OFF position by a user.

[0047] The charger (3) may be installed outside the electric vehicle (EV) and communicates with the vehicle controller (2) to supply charging power of constant current or constant voltage through the charging / discharging terminals (P+, P-) of the battery pack (10).

[0048] The battery management system (100) includes a sensing unit (110) and a control unit (120). The battery management system (100) may further include a memory unit (130) and / or a communication unit (140).

[0049] The sensing unit (110) can periodically measure the voltage, current, and temperature of the battery (B) during charging and / or discharging of the battery (B). The sensing unit (110) includes a current sensor (111), a voltage sensor (112), and a temperature sensor (113).

[0050] A current sensor (111) is provided to be electrically connected to the charging and discharging path of the battery (B). The current sensor (111) is configured to output a signal (SI) indicating the magnitude and direction of the current flowing through the battery (B) to the control unit (120). For example, a shunt resistor and / or a Hall effect element may be used as the current sensor (111).

[0051] The voltage sensor (112) can be electrically connected to the positive terminal and the negative terminal of the battery (B). The voltage sensor (112) is configured to detect the voltage across the positive terminal and the negative terminal of the battery (B) and to output a signal (SV) indicating the detected voltage to the control unit (120).

[0052] The temperature sensor (113) is configured to detect the temperature of an area within a predetermined distance from the battery (B) and to output a signal (ST) indicating the detected temperature to the control unit (120). For example, a thermistor having a negative characteristic temperature coefficient may be used as the temperature sensor (113).

[0053] The control unit (120) is operably coupled to the sensing unit (110), memory unit (130), communication unit (140), and relay (R). The control unit (120) may be implemented in hardware using at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors, and other electrical units for performing functions.

[0054] The control unit (120) can determine the current value, voltage value, and temperature value from each of the signal (SI), signal (SV), and signal (ST) using an analog-to-digital converter (ADC), and then store them in the memory unit (130).

[0055] The memory unit (130) is operably coupled to the control unit (120). The memory unit (130) may include at least one type of storage medium among, for example, a flash memory type, a hard disk type, an SSD type (Solid State Disk type), an SSD type (Silicon Disk Drive type), a multimedia card micro type, RAM (random access memory; RAM), SRAM (static random access memory), ROM (read-only memory; ROM), EEPROM (electrically erasable programmable read-only memory), and PROM (programmable read-only memory). Although the memory unit (130) is depicted in FIG. 1 as being distinct from the control unit (120), the memory unit (130) may be embedded as a sub-component of the control unit (120).

[0056] The control unit (120) can generate voltage time series data, current time series data, temperature time series data and / or SOC time series data during charging and discharging of the battery (B) based on signals (SV, SI and / or ST) collected from the sensing unit (110).

[0057] The communication unit (140) can be coupled to communicate with the vehicle controller (2). The communication unit (140) can transmit battery information of the battery (B) received from the control unit (120) to the vehicle controller (2). The communication unit (140) can communicate with the vehicle controller (2) via a wired network such as a LAN (local area network), CAN (controller area network), daisy chain, and / or a short-range wireless network such as Bluetooth, Zigbee, Wi-Fi.

[0058] The control unit (120) can determine the maximum capacity or state of health (SOH) of the battery (B). The maximum capacity represents the maximum amount of charge that can be stored in the battery (B) and may also be referred to as the "full charge capacity." For example, the maximum capacity is equal to the value of the accumulated current flowing while discharging the battery (B), which has a state of charge (SOC) of 1 (=100%), until the state of charge becomes 0 (=0%).

[0059] The control unit (120) can determine the SOH or maximum capacity of the battery (B) based on the SOC at each of two different time points and the current accumulated during the period between the two time points using the following Equation 1. Let the first of the two time points be t1 and the second time point be t2.

[0060] <Formula 1>

[0061]

[0062] In Formula 1, Q ref is the reference capacity, SOC1 is the SOC estimated at time t1, SOC2 is the SOC estimated at time t2, ΔSOC is the difference between SOC1 and SOC2, i t ε is the current value representing the current detected at time t between time t1 and time t2, ΔC is the integrated current value accumulated during the period from time t1 to time t2, Q est is the estimate of the maximum capacity at time t2, SOH new represents the estimate of SOH at time t2. Q ref is a predetermined value representing the maximum capacity when the SOH of the battery (B) is 1. Q ref This can be referred to as the 'design capacity' or 'initial buffer capacity' and may be stored in advance in the memory unit (130).

[0063] The control unit (120) can periodically determine the SOC of the battery (B) during charging and / or discharging based on the current value of the battery information using ampere counting (see Equation 2).

[0064] <Equation 2>

[0065]

[0066] The symbols used in Equation 2 are explained as follows. Δt can represent the measurement period of a group of battery parameters including voltage, current, and temperature (i.e., the time interval between two adjacent measurement timings). k can be a time index that increases by 1 for every Δt elapsed.

[0067] The inverter (30) may include at least one of a DC-AC inverter and a DC-DC converter. The inverter (30) may convert direct current power (discharge power) supplied from the battery (B) into alternating current power and supply it to the motor (40) during the discharge of the battery (B). The electric load (40) may include a three-phase alternating current motor that generates kinetic energy for driving an electric vehicle (EV).

[0068] The peripheral device (50) may include vehicle sensor(s) that measure at least one parameter (e.g., vehicle speed, etc.) related to the state of the electric vehicle (EV). The peripheral device (50) may include an output device (e.g., display, speaker) that provides information received from the battery management system (100) and / or the vehicle controller (2) in a form recognizable by the user. The peripheral device (50) may be driven using direct current power or alternating current power supplied from the inverter (30).

[0069] Figure 2 is a graph that exemplarily shows the change in the remaining capacity of a battery over time.

[0070] Referring to FIG. 2, the sign t Acan indicate the point in time when charging started during the idle period of the battery (B). That is, time t A The charging period of the battery (B) begins from this point.

[0071] During charging, the remaining capacity of the battery (B) continuously increases, and when charging stops, the increase in the remaining capacity of the battery (B) stops. In FIG. 2, the remaining capacity of the battery (B) is at time t B The highest point at (i.e., Q B Since it reaches ), the charging period of the battery (B) is at time t A From time t B It can be said that it goes up to.

[0072] time point t B Since the remaining capacity of the battery (B) decreases from time t B It can be said that the discharge period of the battery (B) begins at the same time as the charging period ends. Of course, unlike the example in FIG. 2, there may be a rest period between the end of the charging period and the start of the discharge period during which both charging and discharging are stopped.

[0073] At time t1, the remaining capacity of battery (B) is Q during the charging of battery (B). A It could be the point in time when it was reached. Q A is Q B See Q th It can be as small as that.

[0074] At time t2, the remaining capacity of the battery (B) is Q during the discharge of the battery (B). A It may be the point in time when it is reached. That is, the remaining capacity of the battery (B) at time t1 and the remaining capacity of the battery (B) at time t2 are Q A It can be the same as.

[0075] time point t C can indicate the point in time when the discharge of the battery (B) stops. For example, at time t B From [date], the electric vehicle (EV) drives using the discharge power of the battery (B), until [date] at time t CThe electric vehicle (EV) may have been turned off at time t. Therefore, the discharge period of the battery (B) is at time t B From time t C It can be said that it goes up to.

[0076] The control unit (120) has an increase in the remaining capacity of the battery (B) during the charging period and a decrease in the remaining capacity of the battery (B) during the discharging period, both of which are critical capacities (Q th If the above is true, a first period within the charging period and a second period within the discharging period can be determined.

[0077] The start and end times of the first period are t1 and t, respectively. B It can be. Specifically, the maximum remaining capacity (Q) during the charging period B The point in time corresponding to ) can be set as the end point of the first period, and the remaining capacity is at the maximum value (Q B Critical capacity (Q) greater than ) th A point in time smaller than ) can be set as the start point of the first period.

[0078] The start and end times of the second period are t, respectively. B and t2 may be used. Specifically, the maximum remaining capacity (Q) during the discharge period. B The point in time corresponding to ) can be set as the start time of the second period, and the remaining capacity is at the maximum value (Q B Critical capacity (Q) greater than ) th A point in time smaller than ) can be set as the end point of the second period.

[0079] The control unit (120) can generate charging monitoring information based on signals collected from the sensing unit (110) during the charging period. The control unit (120) can generate discharging monitoring information based on signals collected from the sensing unit (110) during the discharging period.

[0080] The charging monitoring information may include voltage time series data and current time series data of the battery (B) for a first period. The charging monitoring information may further include at least one of temperature time series data and SOC time series data of the battery (B) for a first period.

[0081] The discharge monitoring information may include voltage time series data and current time series data of the battery (B) for the second period. The discharge monitoring information may further include at least one of temperature time series data and SOC time series data of the battery (B) for the second period.

[0082] When the first period is determined, the control unit (120) can determine the charging energy of the battery (B) for the first period. Likewise, when the second period is determined, the control unit (120) can determine the discharging energy of the battery (B) for the second period.

[0083] The first period is when the remaining capacity of the battery (B) is the critical capacity (Q th Since the period increases by ), the current integrated value (which may be an absolute value) during the first period is the critical capacity (Q th It can be the same as ). The second period is when the remaining capacity of the battery (B) is the critical capacity (Q th Since it is a period of decrease by ), the current integrated value (which may be an absolute value) during the second period is also the critical capacity (Q th It can be the same as ).

[0084] The following Equation 3 can be used to determine the charging energy for the first period and / or the discharging energy for the second period.

[0085] <Equation 3>

[0086]

[0087] E in Formula 3 bIf represents the charging energy for the first period, j may indicate a time index corresponding to the start time of the first period, and M may indicate a time index corresponding to the end time of the first period.

[0088] E in Formula 3 b If represents the discharge energy for the second period, j may indicate a time index corresponding to the start time of the second period, and M may indicate a time index corresponding to the end time of the second period. k may be a natural number within the range from j to M.

[0089] V[k] can indicate the voltage value mapped to the k-th time index, and I[k] can indicate the current value mapped to the k-th time index, respectively.

[0090] Figure 3 is an example of a data table referenced to explain the process of determining the first degradation factor.

[0091] Referring to FIG. 3, the leftmost column of the data table (300) indicates the number of diagnostic processes executed for the battery (B). For example, the first data row associated with diagnostic number = 1 may be associated with the first diagnostic process executed for the battery (B), and the last data row associated with diagnostic number = 1300 may be associated with the 1300th diagnostic process executed for the battery (B).

[0092] Naturally, whenever the diagnostic process is executed, the first period and the second period are newly determined, and thus the charging energy for the first period and the discharging energy for the second period, as well as other information based thereon, can also be updated.

[0093] Whenever the diagnostic process is executed, the control unit (120) determines the first diagnostic value, the second diagnostic value, the third diagnostic value, and the first deterioration factor in order, and then maps at least the first deterioration factor among the first diagnostic value, the second diagnostic value, the third diagnostic value, and the first deterioration factor to the diagnostic cycle (or other information related thereto) and records it in the memory unit (130).

[0094] The first diagnostic value can represent the ratio of charging energy to discharge energy. For example, at diagnostic cycle = 1300, the first diagnostic value = 123.18 [kWh] / 118.59 [kWh] = 1.0387. The first diagnostic value and the Coulomb efficiency can have an inverse relationship.

[0095] The second diagnostic value may represent the ratio (percentage) of the difference between the first diagnostic value and the reference value relative to the reference value. The reference value may be recorded in the memory unit (130) as 1.0202, which is the first diagnostic value at the beginning of the lifespan (e.g., diagnostic cycle = 1). For example, at diagnostic cycle = 1300, the second diagnostic value = (1.0387 - 1.0202) / 1.0202 100% = 1.81%.

[0096] The third diagnostic value may represent an estimate of the rate of increase (percentage) of internal resistance at a specific diagnostic cycle relative to the internal resistance at the beginning of the life cycle. The third diagnostic value may be a second diagnostic value adjusted based on a predetermined scaling constant. For example, the third diagnostic value may be a value obtained by multiplying the second diagnostic value by a scaling constant (e.g., 10). The scaling constant may be predetermined based on the results of multiple charge-discharge tests using standard charging conditions and standard discharging conditions performed on test batteries (B) of the same type as the battery (B).

[0097] The relationship between the charging energy, discharging energy, first diagnostic value, second diagnostic value, and third diagnostic value can be expressed as shown in Equation 4 below.

[0098] <Equation 4>

[0099]

[0100] In Formula 4, D1 is the first diagnostic value, D2 is the second diagnostic value, D3 is the third diagnostic value, E ch is charging energy, E disch is the discharge energy, A is the reference value, and B is the scaling constant.

[0101] For reference, an increase in the number of diagnostic cycles naturally implies an increase in the degree of degradation of the battery (B). As the degree of degradation of the battery (B) increases, the buffer capacity of the battery (B) decreases compared to the early stages of its lifespan, while the internal resistance may increase; consequently, the polarization voltage component of the battery (B) can increase with the same amount of current. The polarization voltage component of the battery (B) manifests as positive polarity during charging, whereas it manifests as negative polarity during discharging. For this reason, according to the data table (300), as the number of diagnostic cycles increases, a trend of increasing charging energy and a trend of decreasing discharging energy can be observed. Also, for the same reason, the charging energy per diagnostic cycle may be greater than the discharging energy.

[0102] For each diagnostic cycle, the control unit (120) can determine the third diagnostic value as the first deterioration factor.

[0103] Alternatively, the control unit (120) may determine a first degradation factor for at least one diagnostic cycle based on the history data (310) of the third diagnostic value. The history data (310) of the third diagnostic value includes third diagnostic values ​​sorted according to the diagnostic cycle and represents a pattern of change in the third diagnostic value as the diagnostic cycle increases. For example, if a total of 1,300 diagnostic processes have been executed to date, the history data (310) of the third diagnostic value may include a total of 1,300 third diagnostic values. The control unit (120) may determine a first degradation factor for at least one diagnostic cycle by applying data smoothing logic to the history data (310) of the third diagnostic value. For example, when data smoothing logic is applied to the history data (310) of the third diagnostic value, history data (320) of the first degradation factor may be generated. As for data smoothing logic, any one or a combination of two or more known techniques such as linear regression, moving average, multi-order fitting, exponential fitting, and exponential smoothing may be used.

[0104] FIG. 4 is a flowchart schematically illustrating a battery management method according to a first embodiment of the present invention. The method of FIG. 4 can be executed periodically during the operation of a battery management system (100).

[0105] Referring to FIG. 4, in step S410, the control unit (120) has a charging period (e.g., t in FIG. 2). A ~t B Generates charging monitoring information for the battery (B) for ).

[0106] In step S420, the control unit (120) has a discharge period (e.g., t in FIG. 2). B ~t C Generates discharge monitoring information for the battery (B) for ).

[0107] As illustrated in FIG. 2, the discharge period may follow the charging period. That is, the charging period and the discharge period related to the method according to FIG. 4 may be continuous, or there may be a temporary pause between the charging period and the discharge period. Preferably, the time difference between the end point of the charging period and the start point of the discharge period may be limited to a predetermined threshold time. That is, if discharge does not proceed even after the threshold time has elapsed from the end point of the charging period, the diagnostic process related to the already completed charging period may not be executed.

[0108] In step S430, the control unit (120) determines that the increase in the remaining capacity of the battery (B) during the charging period is a critical capacity (Q th ) or more, and the decrease in the remaining capacity of the battery (B) during the discharge period is the critical capacity (Q th Determine whether it is greater than or equal to ). If the value of step S430 is "Yes", proceed to step S440.

[0109] In step S440, the control unit (120) determines the charging energy of the battery (B) for a first period within the charging period and the discharging energy of the battery (B) for a second period within the discharging period based on the charging monitoring information and the discharging monitoring information (see Equation 3).

[0110] In step S450, the control unit (120) determines a first degradation factor of the battery (B) based on the charging energy and the discharging energy (see Equation 4). The first degradation factor may represent the level of increase in the internal resistance of the battery (B) due to degradation compared to the initial lifespan.

[0111] The method of FIG. 4 may further include step S460. In step S460, the control unit (120) may execute a safety control function based on a first degradation factor. The safety control function may include lowering the maximum charging current, lowering the maximum discharge current, lowering the maximum charging voltage, raising the minimum discharge voltage, turning off the relay, and / or notifying a danger alarm. The relationship between the adjustment amount of the maximum charging current, maximum discharge current, maximum charging voltage, and / or minimum discharge voltage and the first degradation factor may be predetermined.

[0112] Each time the method according to Fig. 4 (i.e., the diagnostic process) is executed, the number of the diagnostic cycle can be increased by 1.

[0113] Meanwhile, during the aforementioned charging period, the actual charging conditions may change moment by moment, and likewise, during the discharge period, the actual discharge conditions may change moment by moment. Here, the charging conditions and discharge conditions may refer to one or more groups of battery parameters (e.g., current, temperature, SOC, etc.) that directly or indirectly affect the degradation diagnosis of the battery (B), and may be newly determined for each measurement period (Δt).

[0114] The greater the fluctuation in actual charging conditions and the larger the difference between actual and standard charging conditions, the greater the error in the charging energy can be. In other words, the charging energy determined based on charging monitoring information for a charging period where actual charging conditions fluctuate frequently may differ significantly from the charging energy that would have been determined if the actual charging conditions had remained constant at standard charging conditions throughout the charging period. Similarly, the discharge energy determined based on discharge monitoring information for a discharge period where actual discharge conditions fluctuate frequently may differ significantly from the discharge energy that would have been determined if the actual discharge conditions had remained constant at standard discharge conditions throughout the discharge period.

[0115] Here, the standard charging conditions may represent individually predetermined standard charging current values, standard temperature values, and / or standard SOC values. For example, the standard charging conditions may be predetermined as standard temperature value = 25[℃], standard charging current value = 3.0[C-rate], and standard SOC value (which may represent the charging start SOC) = 50[%].

[0116] Standard discharge conditions may represent individually predetermined standard discharge current values, standard temperature values, and / or standard SOC values. For example, standard discharge conditions may be predetermined as standard temperature value = 25[°C], standard discharge current value = 3.0[C-rate], and standard SOC value (which may represent the discharge start SOC) = 80[%].

[0117] However, in the actual usage environment of the battery (B) (e.g., driving of an electric vehicle on a road), it is practically impossible to perfectly control the charging and discharging conditions to standard conditions. Therefore, there is a concern that the accuracy of the first degradation factor determined based on the charging and discharging monitoring information obtained in such actual usage environment may be somewhat reduced. Accordingly, if noise components are removed from the first degradation factor based on the history of changes in actual charging conditions over the first period within the charging period and the history of changes in actual discharging conditions over the second period within the discharging period, a more accurate degradation diagnosis result can be obtained.

[0118] FIG. 5 is a drawing referenced to explain a factor correction model provided for correcting a first degradation factor.

[0119] Referring to FIG. 5, the control unit (120) may use a factor correction model (500) to determine a correction factor for removing noise components for a first degradation factor. The factor correction model (500) may be a machine learning model that has been pre-trained by a plurality of training data sets, may be stored in a memory unit (130), and may be executed by the control unit (120). The machine learning model may be a binary tree-based classification model, such as Light GBM, etc.

[0120] Multiple training data sets may be obtained as a result of performing various charge-discharge tests on multiple test batteries. Multiple test batteries may be prepared in advance to have different degrees of degradation. Each of the various charge-discharge tests may simulate various actual charging conditions and various actual discharging conditions that may be experienced in the actual usage environment of the battery (B).

[0121] Each training data set may include (i) a test charge / discharge condition data set, (ii) a test degradation factor, and (iii) a standard degradation factor.

[0122] (i) The test charge / discharge condition data set may include a plurality of test charge conditions and a plurality of test discharge conditions corresponding to a specific charge / discharge test. (ii) The test degradation factor may be a first degradation factor of the test battery based on charge monitoring information and discharge monitoring information of the test battery obtained during the progress of the specific charge / discharge test. (iii) The standard degradation factor may be a first degradation factor of the test battery based on charge monitoring information and discharge monitoring information of the test battery obtained during the progress of a standard charge / discharge test using standard charge conditions and standard discharge conditions. That is, in each training data set, the difference between the test degradation factor and the standard degradation factor may be said to correspond to the magnitude of the noise component present in the test degradation factor caused by the difference between each test charge condition and the standard charge condition of the specific charge / discharge test and the difference between each test discharge condition and the standard discharge condition. Accordingly, through a learning process using multiple learning data sets, a first relationship between [the difference between test charging conditions and standard charging conditions] and [the magnitude of the noise component of the first degradation factor], and a second relationship between [the difference between test discharge conditions and standard discharge conditions] and [the magnitude of the noise component of the first degradation factor] can be learned in the factor correction model (500).

[0123] The factor correction model (500) may be trained to return a correction factor as output data when an actual charge / discharge condition data set of the battery (B) is input as input data. The actual charge / discharge condition data set may include a plurality of actual charge conditions and a plurality of actual discharge conditions determined based on charge monitoring information for a first period and discharge monitoring information for a second period.

[0124] If all of the multiple actual charging conditions are identical to the standard charging conditions and all of the multiple actual discharge conditions are completely identical to the standard discharge conditions, the correction factor output from the factor correction model (500) will be 0. Conversely, if all of the multiple actual charging conditions are significantly different from the standard charging conditions, and all of the multiple actual discharge conditions are significantly different from the standard discharge conditions, the correction factor output from the factor correction model (500) will have a very large absolute value.

[0125] FIG. 6 is a flowchart schematically illustrating a battery management method according to a second embodiment of the present invention. The method of FIG. 6 can be executed periodically during the operation of a battery management system (100).

[0126] Referring to FIG. 6, in step S610, the control unit (120) generates charging monitoring information of the battery (B) for a charging period. Step S610 may be substantially the same as step S410 of FIG. 4.

[0127] In step S620, the control unit (120) generates discharge monitoring information of the battery (B) for the discharge period. Step S620 may be substantially the same as step S420 of FIG. 4.

[0128] In step S630, the control unit (120) determines whether the increase in the remaining capacity of the battery (B) during the charging period is greater than or equal to the reference capacity, and whether the decrease in the remaining capacity of the battery (B) during the discharging period is greater than or equal to the reference capacity. If the value of step S630 is "Yes," the process may proceed to step S640. Step S630 may be substantially the same as step S430 of FIG. 4.

[0129] In step S640, the control unit (120) determines the charging energy of the battery (B) for a first period within the charging period and the discharging energy of the battery (B) for a second period within the discharging period based on the charging monitoring information and the discharging monitoring information (see Equation 3). Step S640 may be substantially the same as step S440 of FIG. 4.

[0130] In step S650, the control unit (120) determines a first degradation factor of the battery (B) based on the charging energy and the discharging energy (see Equation 4). Step S650 may be substantially the same as step S450 of FIG. 4.

[0131] In step S660, the control unit (120) can determine a correction factor based on charging monitoring information and discharging monitoring information. The noise component included in the first degradation factor may be due to the difference between each of the multiple actual charging conditions during the first period and the standard charging condition, and the difference between each of the multiple actual discharging conditions during the second period and the standard discharging condition.

[0132] The control unit (120) can perform an operation to determine a plurality of actual charging conditions based on charging monitoring information for a first period and an operation to determine a plurality of actual discharge conditions based on discharge monitoring information for a second period. Each actual charging condition may be a data point (or data set) representing a current value, a temperature value, and / or an SOC value for each time index of the first period. Each actual discharge condition may be a data point (or data set) representing a current value, a temperature value, and / or an SOC value for each time index of the second period.

[0133] Next, the control unit (120) can obtain a correction factor from the factor correction model (500) by inputting a set of actual charge / discharge condition data, including a plurality of actual charge conditions and a plurality of actual discharge conditions, into the factor correction model (500).

[0134] Alternatively, the control unit (120) may determine a plurality of charging correction values ​​by individually comparing a plurality of actual charging conditions with standard charging conditions, determine a plurality of discharge correction values ​​by individually comparing a plurality of actual discharge conditions with the standard discharge conditions, and then determine a correction factor based on the plurality of charging correction values ​​and the plurality of discharge correction values. In this case, the control unit (120) may determine a plurality of charging correction values ​​that are one-to-one associated with a plurality of actual charging conditions based on first relationship data between charging condition deviation and charging correction values. The charging condition deviation may represent the difference between actual charging conditions and standard charging conditions. Additionally, the control unit (120) may determine a plurality of discharge correction values ​​that are one-to-one associated with a plurality of actual discharge conditions based on second relationship data between discharge condition deviation and discharge correction values. The discharge condition deviation may represent the difference between actual discharge conditions and standard discharge conditions. Equation 5 below is an example of first relationship data, and Equation 6 below is an example of second relationship data.

[0135] <Equation 5>

[0136]

[0137] In Equation 5, C ch [k] is the actual charging condition at the k-th time index within the first period (k-th actual charging condition), C ch_std is standard charging conditions, F ch [k] is a charging correction value for the k-th time index within the first period (k-th charging correction value), and f1 may be a mathematical function that maps the charging condition deviation input thereto to a specific charging correction value. C ch [k] and C ch_std If each is a multidimensional data point as a set of multiple values, the charge condition deviation at the k-th time index is C ch [k] and C ch_std It could be the distance between them.

[0138] <Equation 6>

[0139]

[0140] C disch [k] is the actual discharge condition at the k-th time index within the second period (k-th actual discharge condition), C disch_std is standard discharge condition, F disch [k] is a discharge correction value for the k-th time index within the second period (k-th discharge correction value), and f2 may be a mathematical function that maps the discharge condition deviation input thereto to a specific discharge correction value. C disch [k] and C disch_std If each is a multidimensional data point as a set of multiple values, the discharge condition deviation at the k-th time index is C disch [k] and C disch_std It could be the distance between them.

[0141] The control unit can determine the correction factor using the following Equation 7.

[0142] <Equation 7>

[0143]

[0144] In Equation 7, F correct is a correction factor, a is a time index corresponding to the start time of the first period, b is a time index corresponding to the end time of the first period, c is a time index corresponding to the start time of the second period, and d is a time index corresponding to the end time of the second period.

[0145] In this regard, if most of the multiple actual charging conditions cause an excessive first degradation factor compared to standard charging conditions and / or if most of the multiple actual discharge conditions cause an excessive first degradation factor compared to standard discharge conditions, the correction factor may have a negative value.

[0146] Similarly, if most of the multiple actual charging conditions cause a first degradation factor less than the standard charging condition and / or most of the multiple actual discharge conditions cause a first degradation factor less than the standard discharge condition, the correction factor may have a positive value.

[0147] In step S670, the control unit (120) determines a second degradation factor of the battery (B) by correcting the first degradation factor based on the correction factor. For example, the second degradation factor may be equal to the sum of the first degradation factor and the correction factor.

[0148] The method of FIG. 6 may further include step S680. In step S680, the control unit (120) may execute a safety control function based on a second degradation factor. The safety control function executed in step S680 may be substantially the same as the safety control function described above with respect to step S460 of FIG. 4.

[0149] Each time the method according to Fig. 6 (i.e., the diagnostic process) is executed, the number of the diagnostic cycle can be increased by 1.

[0150] Figure 7 shows the SOH according to the driving distance of an electric vehicle. C and SOH R This is a drawing referenced to exemplarily explain the pattern of change.

[0151] In Fig. 7, SOH C can represent the degree of degradation corresponding to the decrease in buffering capacity. For example, SOH of Equation 1 new SOH C It can be used as. SOH R It may represent a degree of degradation corresponding to an increase in internal resistance and may be based on a first degradation factor or a second degradation factor determined in the manner according to the present invention. For example, SOH R = 2nd Degradation Factor + 100 [%]

[0152] Code 710 is mileage and SOH C Mileage-SOH indicating the relationship between C As a curve, as the driving distance of the electric vehicle (1) equipped with a battery (B) increases, SOH C It shows a decreasing trend. Symbol 720 represents mileage and SOH R Mileage-SOH indicating the relationship between R As a curve, as the driving distance of the electric vehicle (1) equipped with a battery (B) increases, SOH R It shows an increasing tendency.

[0153] The inventor of the present invention [regarding] SOH for the same increase in driving distance C The decrease in and SOH R It was confirmed through multiple verification procedures that the increase was almost similar.

[0154] The control unit (120) is the driving distance-SOH C SOH according to the curve (710) C The decreasing trend of and mileage-SOH R SOH according to the curve (720) R By comparing the increasing trends of the two trends, if the deviation between the two trends exceeds a predetermined allowable value, the aforementioned safety control function can be executed.

[0155] Another embodiment of the present invention may provide a computer-readable medium having a program recorded thereon for executing the various embodiments described above on a computer.

[0156] A program may be implemented as hardware components, software components, and / or a combination of hardware and software components. A program may be executed by any system capable of executing computer-readable instructions.

[0157] Software may include computer programs, code, instructions, or a combination thereof, and may configure a processing unit to operate as desired or command the processing unit independently or collectively.

[0158] Software can be implemented as a computer program containing instructions stored on a computer-readable storage medium. Examples of computer-readable storage media include magnetic storage media (e.g., ROM (read-only memory), RAM (random-access memory), floppy disks, hard disks, etc.) and optical reading media (e.g., CD-ROMs, DVDs (Digital Versatile Discs)). Computer-readable storage media can be distributed across networked computer systems, allowing computer-readable code to be stored and executed in a distributed manner. The storage medium is readable by a computer, stored in memory, and can be executed by a processor.

[0159] Computer-readable media may be provided in the form of non-transitory recording media. Here, 'non-transitory storage media' simply means that it is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily. For example, 'non-transitory storage media' may include a buffer in which data is stored temporarily.

[0160] In addition, the program may be provided as part of a computer program product. Computer program products may be traded between a seller and a buyer as goods.

[0161] A computer program product may include a software program or a computer-readable recording medium on which the software program is stored. For example, a computer program product may include a product in the form of a software program that is distributed electronically through a manufacturer of an electronic device or an electronic market (e.g., a downloadable application). For electronic distribution, at least a portion of the software program may be stored on a recording medium or temporarily created. In this case, the recording medium may be a server of the manufacturer of the electronic device, a server of the electronic market, or a recording medium of a relay server that temporarily stores the software program.

[0162] The embodiments of the present invention described above are not limited to implementation through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which such a program is recorded. Such implementation can be easily achieved by a person skilled in the art to which the present invention pertains, based on the description of the embodiments described above.

[0163] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0164] Furthermore, since the present invention described above allows for various substitutions, modifications, and changes within the scope of the technical concept of the present invention to those skilled in the art without departing from the technical spirit of the present invention, it is not limited by the aforementioned embodiments and attached drawings, but rather all or part of each embodiment may be selectively combined to allow for various modifications.

Claims

1. A step of generating battery charging monitoring information for a charging period; A step of generating discharge monitoring information of the battery for a discharge period following the charging period; If the increase in the remaining capacity of the battery during the charging period is greater than or equal to a critical capacity and the decrease in the remaining capacity of the battery during the discharging period is greater than or equal to the critical capacity, the step of determining the charging energy of the battery for a first period within the charging period and the discharging energy of the battery for a second period within the discharging period based on the charging monitoring information and the discharging monitoring information; and A step of determining a first degradation factor indicating the level of increase in internal resistance of the battery due to degradation compared to the initial lifespan, based on the charging energy and the discharging energy; A battery management method including 2. In Paragraph 1, The above charging monitoring information includes voltage time series data and current time series data of the battery for the first period, and A battery management method wherein the discharge monitoring information includes voltage time series data and current time series data of the battery for the second period.

3. In Paragraph 1, The first period is from the first point in time of the charging period to the end point of the charging period, wherein the current integrated value during the first period is equal to the critical capacity, and A battery management method wherein the second period is from the start of the discharge period to a second point in time within the discharge period, and the current integrated value during the second period is equal to the critical capacity.

4. In Paragraph 1, The step of determining the first degradation factor of the above battery is, A step of determining a primary diagnostic value representing the ratio of the charging energy to the discharge energy; A step of determining a second diagnostic value representing the ratio of the difference between the first diagnostic value and the reference value with respect to a predetermined reference value; A step of determining a third diagnostic value by adjusting the second diagnostic value based on a predetermined scaling constant; and A step of determining the first degradation factor by applying data smoothing logic to the history data of the third diagnostic value; A battery management method including 5. In Paragraph 1, A step of determining a correction factor for removing a noise component included in the first degradation factor based on the above-mentioned charging monitoring information and the above-mentioned discharging monitoring information, wherein the noise component included in the first degradation factor is due to the difference between each of the plurality of actual charging conditions during the first period and the standard charging condition of each of the plurality of actual discharging conditions during the second period; and A step of determining the second degradation factor of the battery by correcting the first degradation factor based on the above correction factor; A battery management method that further includes 6. In Paragraph 5, The above charging monitoring information includes voltage time series data, current time series data, temperature time series data, and SOC time series data of the battery for the first period, and A battery management method comprising the above discharge monitoring information including voltage time series data, current time series data, temperature time series data, and SOC time series data of the battery for the second period.

7. In Paragraph 5, The step of calculating the above correction factor is, The method includes the step of determining the correction factor by inputting a set of actual charge / discharge condition data, including the plurality of actual charge conditions and the plurality of actual discharge conditions, into a factor correction model. The above factor correction model is a machine learning model that has been pre-trained by a plurality of training data sets, a battery management method.

8. In Paragraph 5, The step of calculating the above correction factor is, A step of determining a plurality of charging correction values ​​by individually comparing the plurality of actual charging conditions with the standard charging conditions; A step of determining a plurality of discharge correction values ​​by individually comparing the plurality of actual discharge conditions with the standard discharge conditions; and A step of determining the correction factor based on the plurality of charge correction values ​​and the plurality of discharge correction values; A battery management method including 9. A computer-readable medium storing a program for executing a battery management method according to any one of paragraphs 1 through 8 on a computer.

10. A sensing unit for measuring at least one of the voltage, current, and temperature of the battery; and A processor that generates charging monitoring information of the battery for a charging period based on sensing data from the sensing unit, and generates discharging monitoring information of the battery for a discharging period following the charging period; The above processor is, If the increase in the remaining capacity of the battery during the charging period is greater than or equal to the critical capacity, and the decrease in the remaining capacity of the battery during the discharging period is greater than or equal to the critical capacity, the charging energy of the battery for a first period within the charging period and the discharging energy of the battery for a second period within the discharging period are determined based on the charging monitoring information and the discharging monitoring information. A battery management system configured to determine a first degradation factor indicating the level of increase in internal resistance of the battery due to degradation compared to the initial lifespan, based on the charging energy and the discharging energy.

11. In Paragraph 10, The above processor is, Determine a primary diagnostic value representing the ratio of the charging energy to the discharge energy, and Determine a second diagnostic value representing the ratio of the difference between the first diagnostic value and the reference value with respect to a predetermined reference value, and The third diagnostic value is determined by multiplying the above second diagnostic value by a predetermined scaling constant, and A battery management system configured to determine the first degradation factor by applying data smoothing logic to the history data of the third diagnostic value.

12. In Paragraph 10, The above processor is, Based on the above-mentioned charging monitoring information and the above-mentioned discharging monitoring information, a correction factor for removing noise components included in the first degradation factor is calculated, wherein the noise components included in the first degradation factor are due to the difference between each of the plurality of actual charging conditions during the first period and the predetermined standard charging condition and the difference between each of the plurality of actual discharging conditions during the second period. A battery management system configured to determine a second degradation factor of the battery by correcting the first degradation factor based on the above correction factor.

13. A battery pack comprising a battery management system according to any one of paragraphs 10 through 12.

14. An electric vehicle including a battery pack pursuant to Paragraph 13.

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