Battery SOH estimation apparatus and method

Abstract

A battery SOH estimation apparatus according to an aspect of the present disclosure estimates an SOH of a battery applied to an electric vehicle, the battery SOH estimation apparatus comprising: an SOC value obtaining unit that, during a discharging period from the end of charging of the battery to the start of next charging, obtains an SOC value of the battery corresponding to each driving end time point whenever the electric vehicle ends driving after starting driving; a combination unit that generates a plurality of SOC value pairs by combining two different SOC values according to the number of cases in an SOC value set including SOC values obtained during the discharging period; and an estimation unit that estimates an SOH value of the battery corresponding to the discharging period based on at least one SOC value pair among the plurality of SOC value pairs.

Description

Battery SOH Estimation Device and Method

[0001] This application carries a claim of priority based on Korean Patent Application No. 10-2025-0026036 filed on February 27, 2025, and all contents disclosed in the specification and drawings of said patent application are incorporated into this application.

[0002] The present invention relates to a battery SOH estimation apparatus and method, and more specifically, to a battery SOH estimation apparatus and method for estimating the SOH of a battery applied to an electric vehicle.

[0003] Generally, State of Health (SOH) refers to an indicator representing the health or degradation state of a battery capable of repeated charging and discharging. This SOH indicates how healthy the battery's current state is compared to its initial state. For example, an SOH of 100% represents a brand-new battery.

[0004] Recently, as rechargeable batteries are being applied to various devices such as electric vehicles, Energy Storage Systems (ESS), and portable electronic devices, interest and demand for technology capable of accurately estimating the state of health (SOH) of batteries are increasing.

[0005] In particular, in order to prevent safety accidents or unforeseen damage to users by accurately predicting the driving range, remaining lifespan, and battery replacement timing of electric vehicles, it is necessary to accurately estimate the State of Health (SOH) of the batteries applied to electric vehicles.

[0006] To this end, various SOH estimation techniques have been developed, and generally, SOH estimation techniques that utilize charging data obtained during the battery charging process are widely used.

[0007] However, existing technologies that estimate SOH based on charging data have a problem in that they cannot provide battery SOH information during the driving period of an electric vehicle while the battery is discharging. Furthermore, these existing technologies have the problem that if sufficient rest time is not secured before the start of charging and after the end of charging, it is difficult to estimate SOH or the accuracy of the estimated SOH value decreases.

[0008] The technical problem that the present invention aims to solve is to provide a battery SOH estimation device and method that facilitates the management of an electric vehicle and improves safety by continuously monitoring the battery status of an electric vehicle regardless of whether the electric vehicle is charged or whether sufficient rest time is secured before and after charging.

[0009] A battery SOH estimation device according to one embodiment of the present invention is a device for estimating the State of Health (SOH) of a battery applied to an electric vehicle, and comprises: a SOC value acquisition unit that acquires a State of Charge (SOC) value of the battery corresponding to each time the electric vehicle starts driving and ends driving during a discharge period from the end of charging of the battery until the start of the next charge; a combination unit that generates a plurality of SOC value pairs by combining two different SOC values ​​according to the number of cases from a set of SOC values ​​including SOC values ​​acquired during the discharge period; and an estimation unit that estimates the SOH value of the battery corresponding to the discharge period based on at least one SOC value pair among the plurality of SOC value pairs.

[0010] In one embodiment, the SOC value acquisition unit may be configured to determine the point in time after a predetermined time has elapsed since the electric vehicle was parked as the driving end time of the electric vehicle.

[0011] In one embodiment, the SOC value acquisition unit may be configured to further acquire the SOC value of the battery corresponding to the first driving start time of the electric vehicle during the discharge period.

[0012] In one embodiment, the estimation unit may include: a selection module configured to select a pair of SOC values ​​by combining two SOC values ​​whose difference between them is greater than or equal to a predetermined reference value among the plurality of SOC value pairs; a calculation module configured to calculate a candidate SOH value corresponding to the discharge period based on the selected SOC value pair; and a determination module configured to determine the SOH value of the battery corresponding to the discharge period based on the candidate SOH value.

[0013] In one embodiment, the calculation module may be configured to calculate a reference discharge capacity based on the difference between the SOC values ​​forming the selected SOC value pair, and to calculate the candidate SOH value by comparing the reference discharge capacity with the discharge capacity of the battery.

[0014] In one embodiment, the calculation module is configured to calculate a corrected candidate SOH value by correcting the candidate SOH value so as to eliminate an error caused by the candidate SOH value being calculated based on the discharge of the battery, and the determination module may be configured to determine the SOH value of the battery corresponding to the discharge period based on the corrected candidate SOH value.

[0015] In one embodiment, the calculation module may be configured to calculate two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs when two or more SOC value pairs are selected among the plurality of SOC value pairs.

[0016] In one embodiment, the determination module may be configured to determine the median of the two or more candidate SOH values ​​as the SOH value corresponding to the discharge period.

[0017] In one embodiment, the battery SOH estimation device may further include a correction unit that corrects the SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average when SOH values ​​corresponding to a plurality of different discharge periods are estimated.

[0018] An electric vehicle according to another aspect of the present invention includes the battery SOH estimation device described above.

[0019] A battery SOH estimation method according to another aspect of the present invention is a method for a processor to estimate the State of Health (SOH) of a battery applied to an electric vehicle, comprising: a step of obtaining a State of Charge (SOC) value of the battery corresponding to each time the electric vehicle starts driving and ends driving during a discharge period from the end of charging of the battery until the start of the next charge; a step of generating a plurality of SOC value pairs by combining two different SOC values ​​according to a number of cases from a set of SOC values ​​including the SOC values ​​obtained during the discharge period; and a step of estimating the SOH value of the battery corresponding to the discharge period based on at least one SOC value pair among the plurality of SOC value pairs.

[0020] In one embodiment, the estimating step may include, before estimating the battery SOH value corresponding to the discharge period, a step of selecting a pair of SOC values ​​from among a plurality of SOC value pairs, wherein the difference between two SOC values ​​is greater than or equal to a predetermined reference value; a step of calculating a candidate SOH value corresponding to the discharge period based on the selected SOC value pair; and a step of determining the SOH value of the battery corresponding to the discharge period based on the candidate SOH value.

[0021] In one embodiment, the calculating step may include the step of calculating two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs when two or more SOC value pairs are selected among the plurality of SOC value pairs.

[0022] In one embodiment, the determining step may include determining the median of the two or more candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

[0023] In one embodiment, the battery SOH estimation method may further include a step of correcting the SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average when SOH values ​​corresponding to a plurality of different discharge periods are estimated after the estimation step.

[0024] According to the present invention, since the SOH value of a battery is estimated based on the SOC values ​​of the battery obtained whenever the electric vehicle finishes driving during the discharge period from the end of charging to the start of the next charge of the battery applied to the electric vehicle, the SOH of the battery can be estimated at a higher frequency than when the SOH is estimated based only on charging data obtained during the charging period. As a result, the battery status of the electric vehicle can be continuously monitored regardless of whether the electric vehicle is charged or whether sufficient rest time is secured before and after charging, thereby facilitating the management of the electric vehicle and improving safety.

[0025] In addition, in a set of SOC values ​​including SOC values ​​obtained during the discharge period, different SOC values ​​are combined in pairs according to the number of cases to generate multiple SOC value pairs, and since the SOH value corresponding to the discharge period is estimated based on at least one selected SOC value pair among these multiple SOC value pairs, it is possible to provide the effect of estimating the SOH value by collecting data in various different situations and improve the accuracy and reliability of the estimated SOH value.

[0026] In addition, among the plurality of SOC value pairs, SOC value pairs in which the difference between the SOC values ​​is greater than or equal to a predetermined reference value are selected, and candidate SOH values ​​corresponding to the discharge period are calculated based on the selected SOC value pairs, and then the final SOH value corresponding to the discharge period is determined based on these candidate SOH values, thereby ensuring robustness against noise and further improving the accuracy and reliability of the SOH value.

[0027] In addition, since the final SOH value is determined based on candidate SOH values ​​corrected for errors arising from calculations based on battery discharge, the problem where the SOH estimated based on discharge is lower than the experimentally estimated SOH can be resolved.

[0028] Furthermore, a person skilled in the art to which the present invention pertains will readily understand from the following description that various embodiments according to the present invention can solve various technical problems not mentioned above.

[0029] FIG. 1 is a block diagram showing a battery SOH estimation device according to one embodiment of the present invention.

[0030] Figure 2 is a diagram showing a method of combining SOC values.

[0031] FIG. 3 is a block diagram showing the estimation section of a battery SOH estimation device according to one embodiment of the present invention.

[0032] FIG. 4 is a flowchart illustrating a battery SOH estimation method according to one embodiment of the present invention.

[0033] FIG. 5 is a flowchart illustrating the process of determining the SOH value of a battery SOH estimation method according to one embodiment of the present invention.

[0034] Figure 6 is a graph showing the trend of change in the SOH value of an electric vehicle battery according to the driving distance of the electric vehicle.

[0035] FIG. 7 is a drawing showing a battery pack according to one embodiment of the present invention.

[0036] FIG. 8 is a drawing showing an electric vehicle according to one embodiment of the present invention.

[0037] Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings to clarify solutions corresponding to the technical problems of the present invention. However, in describing the present invention, if a description of related prior art would obscure the essence of the present invention, such description may be omitted. Furthermore, terms used in this specification are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of designers, manufacturers, etc. Therefore, the definitions of terms described below should be based on the content throughout this specification.

[0038] FIG. 1 is a block diagram showing a battery SOH estimation device according to one embodiment of the present invention.

[0039] As illustrated in FIG. 1, a battery SOH estimation device (100) according to one embodiment of the present invention includes a control unit (110). This control unit (110) is configured to estimate the State of Health (SOH) of a battery applied to an electric vehicle.

[0040] To this end, the control unit (110) may include at least one processor, such as a general-purpose processor or an ASIC (application-specific integrated circuit), to execute SOH estimation logic, and may optionally include hardware such as registers and memory according to the embodiment.

[0041] Additionally, the control unit (110) may be composed of a combination of hardware, such as a processor, and software, such as a program. That is, the SOH estimation logic of the control unit (110) may be composed of a program and stored in the control unit (110)'s own memory or in the storage unit (140) described later, and the stored program may be executed through the hardware of the control unit (110).

[0042] Meanwhile, the control unit (110) includes detailed components for estimating the SOH of a battery applied to an electric vehicle, such as an SOC value acquisition unit (112), a combination unit (114), and an estimation unit (116).

[0043] The above SOC value acquisition unit (112) is configured to acquire the State of Charge (SOC) value of the battery corresponding to each time the electric vehicle starts driving and ends driving during the discharge period from the end of charging of the battery until the start of the next charge, and each time the electric vehicle starts driving and ends driving.

[0044] In this case, the SOC value acquisition unit (112) can determine the point in time after a predetermined time has elapsed since the electric vehicle was parked as the driving end time of the electric vehicle, and acquire the SOC value of the battery corresponding to the determined driving end time. For example, the SOC value acquisition unit (112) can determine the point in time after 5 minutes have elapsed since the electric vehicle was parked as the driving end time.

[0045] In one embodiment, the SOC value acquisition unit (112) may be configured to measure the voltage and current of the battery over time using a voltage sensor and a current sensor, and to acquire the SOC value of the battery based on the measured values.

[0046] In another embodiment, the SOC value acquisition unit (112) may be configured to acquire the SOC value of the battery from a Battery Management System (BMS) that manages the battery or an Electronic Control Unit (ECU) that controls the electric vehicle.

[0047] Additionally, the SOC value acquisition unit (112) may be configured to further acquire the SOC value of the battery corresponding to the first driving start time of the electric vehicle during the discharge period. For example, if the electric vehicle repeats the start and end of driving nine times between the end of charging the battery and the start of the next charge, the SOC value acquisition unit (112) may acquire the SOC value of the battery corresponding to the first driving start time among the nine driving start times.

[0048] The above combination unit (114) is configured to generate multiple pairs of SOC values ​​by combining two different SOC values ​​according to the number of cases in a set of SOC values ​​including SOC values ​​obtained during the discharge period.

[0049] For example, if the electric vehicle repeats the start and end of driving n times during the discharge period, the combination unit (114) n+1 C2 pairs of SOC values ​​can be generated. Here, n+1 is the sum of the SOC value corresponding to the start time of the first drive and the SOC values ​​corresponding to the end times of n drives, respectively.

[0050] The above estimation unit (116) is configured to estimate the SOH value of the battery corresponding to the discharge period based on at least one SOC value pair among a plurality of SOC value pairs generated by the combination unit (114).

[0051] In one embodiment, the estimation unit (116) may be configured to select a pair of SOC values ​​that combine two SOC values, the difference between them being greater than or equal to a predetermined reference value, from among a plurality of SOC value pairs generated by the combination unit (114), calculate a candidate SOH value corresponding to the discharge period based on the selected SOC value pair, and then determine the SOH value of the battery corresponding to the discharge period based on the candidate SOH value.

[0052] For example, when one SOC value pair is selected among the plurality of SOC value pairs, the estimation unit (116) can calculate one candidate SOH value corresponding to the selected SOC value pair and determine the calculated candidate SOH value as the SOH value of the battery corresponding to the discharge period.

[0053] On the other hand, when two or more pairs of SOC values ​​are selected among the plurality of SOC value pairs, the estimation unit (116) can calculate two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs, and determine the median of the two or more candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

[0054] In this way, since the median value rather than the average value of two or more candidate SOH values ​​is finally determined as the SOH value of the battery, robustness against noise or singularities occurring during the SOH estimation process can be ensured.

[0055] In one embodiment, the control unit (110) may further include a correction unit (118).

[0056] In this case, the correction unit (118) may be configured to correct the SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average when the SOH values ​​corresponding to each of the different multiple discharge periods are estimated.

[0057] For example, the correction unit (118) may sequentially list the estimated SOH values ​​while the battery's charge / discharge cycle is repeated several times, calculate the average value of the n-th estimated SOH value and a predetermined number of SOH values ​​estimated prior to the n-th, and finally determine the calculated average value as the SOH value corresponding to the n-th discharge cycle. In this case, a weight may be assigned to each of the sequentially listed SOH values.

[0058] In one embodiment, the control unit (110) may be configured to control the communication unit (120) described below to transmit the SOH value of the battery to a Battery Management System (BMS) that manages the battery, or to transmit it to a pre-designated server or communication terminal.

[0059] In this case, the server may be a control server that remotely monitors the status of the electric vehicle. Additionally, the communication terminal may be a communication terminal used by the user of the electric vehicle.

[0060] In one embodiment, the control unit (110) may be configured to control the output unit (150) described below to output the SOH value of the battery as a visual signal and / or an acoustic signal.

[0061] The SOC value acquisition unit (112), combination unit (114), estimation unit (116), and correction unit (118) of the above-described control unit (110) may be implemented as a combination of a processor and a program executed by such processor. In this case, the control unit (110) may be implemented as a single processor or as two or more processors that interact with each other.

[0062] In one embodiment, the battery SOH estimation device (100) may further include a communication unit (120). The communication unit (120) may be configured to receive data transmitted from a BMS managing the battery, or from a remotely located server or communication terminal, and transmit it to a control unit (110), or to transmit the SOH value of the battery estimated by the control unit (110) to the BMS, server, or communication terminal. To this end, the communication unit (120) may include a communication modem that performs wired communication and / or wireless communication.

[0063] In one embodiment, the battery SOH estimation device (100) may further include an input unit (130). The input unit (130) may be configured to receive commands or data from a user or administrator. To this end, the input unit (130) may include an input device such as a keyboard, operation buttons, or a touch panel.

[0064] In one embodiment, the battery SOH estimation device (100) may further include a storage unit (140). The storage unit (140) may be configured to store and manage programs or data necessary for the operation of the battery SOH estimation device (100). To this end, the storage unit (140) may include at least one of a ROM, RAM, EEPROM, register, flash memory, CD-ROM, magnetic tape, hard disk, floppy disk, and optical data recording device.

[0065] In one embodiment, the battery SOH estimation device (100) may further include an output unit (150). The output unit (150) may be configured to output the SOH value estimated by the control unit (110) as a visual signal and / or an acoustic signal. To this end, the output unit (150) may include at least one of a display device such as a light-emitting diode, a monitor, a display panel, a touch screen, etc., and an acoustic device such as a speaker.

[0066] Figure 2 is a diagram showing a method of combining SOC values.

[0067] As illustrated in FIG. 2, when an electric vehicle repeats the start and end of driving nine times during the discharge period of the battery, the SOC value acquisition unit (112) can acquire an SOC value corresponding to the first driving start time t0 and SOC values ​​corresponding to the nine driving end times t1-t9, respectively.

[0068] Next, the combination unit (114) combines two different SOC values ​​according to the number of cases from a set of SOC values ​​including 10 SOC values. 10 It is possible to generate C2, or 45, pairs of SOC values.

[0069] Then, the estimation unit (116) can estimate the SOH value of the battery corresponding to the discharge period based on 45 pairs of SOC values.

[0070] FIG. 3 is a block diagram showing the estimation section of a battery SOH estimation device according to one embodiment of the present invention.

[0071] As illustrated in FIG. 3, the estimation unit (116) may include a selection module (116a), a calculation module (116b), and a decision module (116c).

[0072] The selection module (116a) may be configured to select a pair of SOC values ​​that combine two SOC values, among a plurality of SOC value pairs generated by the combination unit (114), such that the difference between them is greater than or equal to a predetermined reference value (e.g., 25%).

[0073] The above calculation module (116b) may be configured to calculate a candidate SOH value corresponding to the discharge period based on a selected SOC value pair.

[0074] For example, the above-mentioned calculation module (116b) can calculate a candidate SOH value (SOHc) as shown in Equation 1 below.

[0075]

[0076] In Equation 1, i is the discharge current of the battery, ta and tb are driving end times corresponding to the SOC values ​​of the SOC value pair, respectively, Cr is the reference capacity of the battery, and △DoD is the amount of change in the depth of discharge of the battery that occurs during the time elapsed from ta to tb. Additionally, △DoD corresponds to the difference between the first SOC value corresponding to time ta and the second SOC value corresponding to time tb among the first and second SOC values ​​of the SOC value pair.

[0077] That is, the above calculation module (116b) can calculate a reference discharge capacity (Cr×△DoD) based on the difference between the SOC values ​​forming a selected SOC value pair, and calculate a candidate SOH value (SOHc) by comparing the reference discharge capacity with the actual discharge capacity of the battery.

[0078] Meanwhile, when two or more pairs of SOC values ​​are selected by the selection module (116a), the calculation module (116b) can calculate two or more candidate SOH values ​​corresponding to each of the two or more pairs of SOC values.

[0079] The above determination module (116c) may be configured to determine the SOH value of the battery corresponding to the discharge period based on the calculated candidate SOH value.

[0080] For example, if two or more candidate SOH values ​​are calculated by the calculation module (116b), the determination module (116c) can determine the median of the two or more calculated candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

[0081] In this way, since the median value rather than the average value of two or more candidate SOH values ​​is finally determined as the SOH value of the battery, robustness against noise or singularities occurring during the SOH estimation process can be ensured.

[0082] In one embodiment, the calculation module (116b) may be configured to calculate a corrected candidate SOH value by correcting the candidate SOH value so that an error caused by the candidate SOH value being calculated based on the discharge of the battery is eliminated. To this end, the calculation module (116b) may include a machine learning model trained to correct the error of the candidate SOH value. In another embodiment, the calculation module (116b) may be configured to pre-store correction data corresponding to each of the calculable candidate SOH values ​​and to correct the actual calculated candidate SOH value using the stored correction data.

[0083] In this case, the determination module (116c) can determine the SOH value of the battery corresponding to the discharge period based on the corrected candidate SOH value.

[0084] In this way, since the final SOH value is determined based on candidate SOH values ​​corrected for errors arising from calculations based on battery discharge, the problem where the SOH estimated based on discharge is lower than the experimentally estimated SOH can be resolved, and the accuracy of the estimated SOH value can be improved.

[0085] FIG. 4 is a flowchart illustrating a battery SOH estimation method according to an embodiment of the present invention. The battery SOH estimation method according to the present invention can be performed in a control unit (110) of the battery SOH estimation device (100) described above, and such a control unit (110) can be implemented as a processor. That is, the battery SOH estimation method according to the present invention can be performed by a processor.

[0086] As illustrated in FIG. 4, the processor obtains the State of Charge (SOC) value of the battery corresponding to each time the electric vehicle starts driving and ends driving during the discharge period from the end of charging of the battery until the start of the next charge (S410).

[0087] In this case, the processor may determine a point in time after a predetermined amount of time has elapsed since the electric vehicle was parked as the driving end time of the electric vehicle, and obtain the SOC value of the battery corresponding to the determined driving end time. For example, the processor may determine a point in time after 5 minutes have elapsed since the electric vehicle was parked as the driving end time.

[0088] In one embodiment, the processor measures the voltage and current of the battery over time using a voltage sensor and a current sensor, and obtains the SOC value of the battery based on the measured values.

[0089] In another embodiment, the processor may be configured to obtain the SOC value of the battery from a Battery Management System (BMS) that manages the battery or an Electronic Control Unit (ECU) that controls the electric vehicle.

[0090] Additionally, the processor may be configured to further acquire the SOC value of the battery corresponding to the first driving start time of the electric vehicle during the discharge period. For example, if the electric vehicle repeats the start and end of driving nine times between the end of charging the battery and the start of the next charge, the processor may acquire the SOC value of the battery corresponding to the first driving start time among the nine driving start times.

[0091] Next, the processor generates multiple pairs of SOC values ​​by combining two different SOC values ​​according to the case from a set of SOC values ​​including SOC values ​​obtained during the discharge period (S420).

[0092] For example, if the electric vehicle repeats the start and end of driving n times during the discharge period, the processor n+1 C2 pairs of SOC values ​​can be generated. Here, n+1 is the sum of the SOC value corresponding to the start time of the first drive and the SOC values ​​corresponding to the end times of n drives, respectively.

[0093] Next, the processor estimates the SOH value of the battery corresponding to the discharge period based on at least one of the plurality of SOC value pairs (S430).

[0094] For example, the processor may select a pair of SOC values ​​from among the plurality of SOC value pairs, wherein the difference between two SOC values ​​is greater than or equal to a predetermined reference value, calculate a candidate SOH value corresponding to the discharge period based on the selected SOC value pair, and then determine the SOH value of the battery corresponding to the discharge period based on the candidate SOH value.

[0095] Meanwhile, when two or more pairs of SOC values ​​are selected among the plurality of SOC value pairs, the processor may calculate two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs, and determine the median of the two or more candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

[0096] In this way, since the median value rather than the average value of two or more candidate SOH values ​​is finally determined as the SOH value of the battery, robustness against noise or singularities occurring during the SOH estimation process can be ensured.

[0097] Next, when SOH values ​​corresponding to different multiple discharge periods are estimated, the processor can correct the SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average (S440).

[0098] For example, the processor may sequentially list the estimated SOH values ​​while the battery's charge-discharge cycle is repeated multiple times, calculate the average value of the n-th estimated SOH value and a predetermined number of SOH values ​​estimated prior to the n-th, and finally determine the calculated average value as the SOH value corresponding to the n-th discharge cycle. In this case, a weight may be assigned to each of the sequentially listed SOH values.

[0099] In one embodiment, the processor may be configured to control the communication unit (120) described above to transmit the SOH value of the battery to a Battery Management System (BMS) that manages the battery, or to transmit it to a pre-designated server or communication terminal.

[0100] In this case, the server may be a control server that remotely monitors the status of the electric vehicle. Additionally, the communication terminal may be a communication terminal used by the user of the electric vehicle.

[0101] In one embodiment, the processor may be configured to control the output unit (150) described above to output the SOH value of the battery as a visual signal and / or an acoustic signal.

[0102] FIG. 5 is a flowchart illustrating the process of determining the SOH value of a battery SOH estimation method according to one embodiment of the present invention.

[0103] As illustrated in FIG. 5, the processor may select a pair of SOC values ​​from among the plurality of SOC value pairs, in order to determine the SOH value corresponding to the discharge period, the SOC value pair is a combination of two SOC values ​​whose difference between them is greater than or equal to a predetermined reference value (e.g., 25%) (S432).

[0104] Next, the processor can calculate a candidate SOH value corresponding to the discharge period based on the selected SOC value pair (S434).

[0105] In this case, the processor can calculate the candidate SOH value (SOHc) using the mathematical formula 1.

[0106] For example, when one SOC value pair is selected among the plurality of SOC value pairs above, the processor can calculate one candidate SOH value corresponding to the selected SOC value pair.

[0107] On the other hand, if two or more SOC value pairs are selected among the plurality of SOC value pairs, the processor can calculate two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs.

[0108] Next, the processor can correct the candidate SOH value so that the error caused by the candidate SOH value being calculated based on the discharge of the battery is eliminated (S436).

[0109] To this end, the processor may include a machine learning model trained to correct errors in candidate SOH values. In another embodiment, the processor may be configured to pre-store correction data corresponding to each of the calculable candidate SOH values ​​and to correct the actual calculated candidate SOH value using the stored correction data.

[0110] Next, the processor can determine the SOH value of the battery corresponding to the discharge period based on the error-corrected candidate SOH value (S438).

[0111] For example, if one candidate SOH value is calculated corresponding to the discharge period, the processor may determine the calculated candidate SOH value as the SOH value of the battery corresponding to the discharge period.

[0112] On the other hand, if two or more candidate SOH values ​​are calculated corresponding to the discharge period, the processor may determine the median of the two or more calculated candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

[0113] In this way, since the final SOH value is determined based on candidate SOH values ​​corrected for errors arising from calculations based on battery discharge, the problem where the SOH estimated based on discharge is lower than the experimentally estimated SOH can be resolved, and the accuracy of the estimated SOH value can be improved.

[0114] In addition, since the median value rather than the average value of two or more candidate SOH values ​​is finally determined as the SOH value of the battery, robustness against noise or outliers occurring during the SOH estimation process can be ensured.

[0115] Meanwhile, embodiments according to the present invention may be implemented as a computer system and a computer program that drives the computer system. When embodiments of the present invention are implemented as a computer program, the components of the present invention may include program segments that execute corresponding operations or tasks through the computer system. Such computer programs or program segments may be stored on various computer-readable recording media. Computer-readable recording media may include all types of media that record data that can be read by a computer system. For example, computer-readable recording media may include ROM, RAM, EEPROM, registers, flash memory, CD-ROM, magnetic tape, hard disk, floppy disk, or optical data recording devices. Furthermore, such recording media may be distributed across computer systems connected by various networks to store or execute program codes in a distributed manner.

[0116] Figure 6 is a graph showing the trend of change in the SOH value of an electric vehicle battery according to the driving distance of the electric vehicle.

[0117] In FIG. 6, the solid line represents the SOH values ​​estimated according to the present invention, and the dotted line represents an experimental example in which the SOH value was estimated for the same battery as the present invention, and the SOH value was estimated based on charging data obtained during the charging process of the battery.

[0118] As shown in Fig. 6, the SOH values ​​estimated according to the present invention show a change trend similar to that of the experimental example, and it can be seen that they have an error within an acceptable range when compared to the SOH values ​​of the experimental example.

[0119] FIG. 7 is a drawing showing a battery pack according to one embodiment of the present invention.

[0120] As illustrated in FIG. 7, the battery pack (10) according to the present invention includes a battery SOH estimation device (100) described with reference to FIG. 1 and a battery (200).

[0121] In one embodiment, the battery pack (10) may optionally further include a measuring device (12), a Battery Management System (BMS) (14), a charging and discharging device (16), and a cooling device (18).

[0122] The measuring device (12) may be configured to measure the voltage and / or current of the battery (200). To this end, the measuring device (12) may include at least one voltage sensor for sensing the voltage of the battery (200) and at least one current sensor for sensing the current of the battery (200). Additionally, the measuring device (12) may include at least one temperature sensor for sensing the temperature of the battery (200).

[0123] The above BMS (14) may be configured to collect data generated by the measuring device (12) to monitor the state of the battery (200) and to manage the charging and discharging processes of the battery. In particular, the above BMS (14) may be configured to generate an hourly SOC value of the battery (200).

[0124] The charging and discharging device (16) may be configured to charge and / or discharge the battery (200). To this end, the charging and discharging device (16) may include a charger for charging the battery (200), a discharger for discharging the battery (200), and at least one switch configured to selectively set or release an electrical connection between the battery (200) and the terminals (T1, T2) of the battery pack (10).

[0125] The cooling device (18) may be configured to cool the battery (200). To this end, the cooling device (18) may include at least one of a heat sink that absorbs heat from the battery (200) and releases it to the outside, and a chiller that provides a cooling liquid to the battery (200).

[0126] A battery SOH estimation device (100) according to one embodiment of the present invention is applied to such a battery pack (10) to estimate the SOH of a battery (200) included in the battery pack (10).

[0127] FIG. 12 is a drawing showing an electric vehicle according to one embodiment of the present invention.

[0128] As illustrated in FIG. 12, an electric vehicle (2) according to one embodiment of the present invention includes a battery pack (10) that provides electrical energy required for driving the electric vehicle, and a battery SOH estimation device (100) according to the present invention.

[0129] In this case, the battery SOH estimation device (100) may be configured to be linked with an ECU (Electronic Control Unit) that controls the operation of the electric vehicle (2) or a BMS of the battery pack (10).

[0130] Additionally, the battery SOH estimation device (100) may be configured to receive data transmitted from a remote server (4) via a wired and / or wireless communication network, or to estimate the SOH value of a battery included in a battery pack (10) and transmit the estimated SOH value to the server (4).

[0131] In another embodiment, the battery SOH estimation device (100) according to the present invention may be configured to be included in the server (4).

[0132] As described above, according to the present invention, since the SOH value of a battery is estimated based on the SOC values ​​of the battery obtained whenever the electric vehicle finishes driving during the discharge period from the end of charging of the battery to the start of the next charge, the SOH of the battery can be estimated at a higher frequency than when the SOH is estimated based only on charging data obtained during the charging period. As a result, the battery status of the electric vehicle can be continuously monitored regardless of whether the electric vehicle is being charged or whether sufficient rest time is secured before and after charging, thereby facilitating the management of the electric vehicle and improving safety.

[0133] In addition, in a set of SOC values ​​including SOC values ​​obtained during the discharge period, different SOC values ​​are combined in pairs according to the number of cases to generate multiple SOC value pairs, and since the SOH value corresponding to the discharge period is estimated based on at least one selected SOC value pair among these multiple SOC value pairs, it is possible to provide the effect of estimating the SOH value by collecting data in various different situations and improve the accuracy and reliability of the estimated SOH value.

[0134] In addition, among the plurality of SOC value pairs, SOC value pairs in which the difference between the SOC values ​​is greater than or equal to a predetermined reference value are selected, and candidate SOH values ​​corresponding to the discharge period are calculated based on the selected SOC value pairs, and then the final SOH value corresponding to the discharge period is determined based on these candidate SOH values, thereby ensuring robustness against noise and further improving the accuracy and reliability of the SOH value.

[0135] In addition, since the final SOH value is determined based on candidate SOH values ​​corrected for errors arising from calculations based on battery discharge, the problem where the SOH estimated based on discharge is lower than the experimentally estimated SOH can be resolved.

[0136] Furthermore, it is obvious that the embodiments according to the present invention can solve various other technical problems in the relevant technical field as well as related technical fields other than those mentioned in this specification.

[0137] The present invention has been described above with reference to specific embodiments. However, those skilled in the art will clearly understand that various modified embodiments may be implemented within the technical scope of the present invention. Therefore, the embodiments disclosed above should be considered in an illustrative rather than a restrictive sense. That is, the true technical scope of the present invention is set forth in the claims, and all variations within the scope of equivalents should be interpreted as being included in the present invention.

[0138] [Explanation of the symbol]

[0139] 2: Electric vehicle, 10: Battery pack, 100: Battery SOH estimation device, 110: Control unit, 112: SOC value acquisition unit, 114: Combination unit, 116: Estimation unit, 118: Correction unit, 120: Communication unit, 130: Input unit, 140: Storage unit, 150: Output unit

Claims

1. A battery SOH estimation device for estimating the State of Health (SOH) of a battery applied to an electric vehicle, A State of Charge (SOC) value acquisition unit that acquires a State of Charge (SOC) value of the battery corresponding to each driving end time whenever the electric vehicle starts driving and ends driving during the discharge period from the end of charging of the battery until the start of the next charging; A combination unit that generates multiple pairs of SOC values ​​by combining two different SOC values ​​according to the case from a set of SOC values ​​including SOC values ​​obtained during the above discharge period; and A battery SOH estimation device comprising an estimation unit that estimates the SOH value of the battery corresponding to the discharge period based on at least one SOC value pair among the plurality of SOC value pairs.

2. In Paragraph 1, A battery SOH estimation device characterized in that the above-described SOC value acquisition unit is configured to determine a point in time after a predetermined time has elapsed since the electric vehicle was parked as the driving end time of the electric vehicle.

3. In Paragraph 1, A battery SOH estimation device characterized in that the above SOC value acquisition unit is configured to further acquire the SOC value of the battery corresponding to the first driving start time of the electric vehicle during the discharge period.

4. In Paragraph 1, The above estimation unit is, A selection module configured to select, among the plurality of SOC value pairs above, a SOC value pair formed by combining two SOC values ​​whose difference between them is greater than or equal to a predetermined reference value; A calculation module configured to calculate a candidate SOH value corresponding to the discharge period based on a selected SOC value pair; and A battery SOH estimation device characterized by including a determination module configured to determine the SOH value of the battery corresponding to the discharge period based on the above candidate SOH value.

5. In Paragraph 4, A battery SOH estimation device characterized by the above-described calculation module being configured to calculate a reference discharge capacity based on the difference between SOC values ​​forming the selected SOC value pair, and to calculate a candidate SOH value by comparing the reference discharge capacity with the discharge capacity of the battery.

6. In Paragraph 5, The above calculation module is configured to calculate a corrected candidate SOH value by correcting the candidate SOH value so that an error caused by the candidate SOH value being calculated based on the discharge of the battery is eliminated. A battery SOH estimation device characterized in that the above-described determination module is configured to determine the SOH value of the battery corresponding to the discharge period based on the above-described corrected candidate SOH value.

7. In Paragraph 4, A battery SOH estimation device characterized in that the above-described calculation module is configured to calculate two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs when two or more SOC value pairs are selected among the plurality of SOC value pairs.

8. In Paragraph 7, A battery SOH estimation device characterized in that the above-described determination module is configured to determine the median of the two or more candidate SOH values ​​as the SOH value corresponding to the discharge period.

9. In Paragraph 1, A battery SOH estimation device characterized by further including a correction unit that corrects SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average when SOH values ​​corresponding to multiple different discharge periods are estimated.

10. The electric vehicle comprising a battery SOH estimation device according to any one of claims 1 to 9.

11. A battery SOH estimation method in which a processor estimates the SOH (State of Health) of a battery applied to an electric vehicle, A step of obtaining a State of Charge (SOC) value of the battery corresponding to each driving end time whenever the electric vehicle starts driving and ends driving during the discharge period from the end of charging of the battery until the start of the next charge; A step of generating a plurality of SOC value pairs by combining two different SOC values ​​according to the case from a set of SOC values ​​including SOC values ​​obtained during the discharge period; and A battery SOH estimation method comprising the step of estimating the SOH value of the battery corresponding to the discharge period based on at least one SOC value pair among the plurality of SOC value pairs.

12. In Paragraph 11, The above-mentioned estimation step is, Before estimating the battery SOH value corresponding to the discharge period, a step of selecting, among the plurality of SOC value pairs, a SOC value pair formed by combining two SOC values ​​whose difference between them is greater than or equal to a predetermined reference value; A step of calculating a candidate SOH value corresponding to the discharge period based on a selected SOC value pair; and A battery SOH estimation method characterized by including the step of determining the SOH value of the battery corresponding to the discharge period based on the above candidate SOH value.

13. In Paragraph 12, The above-mentioned calculation step is, A battery SOH estimation method characterized by including the step of calculating two or more candidate SOH values ​​corresponding to each of the two or more SOC value pairs when two or more SOC value pairs are selected among the plurality of SOC value pairs.

14. In Paragraph 13, The above-mentioned determining step is, A battery SOH estimation method characterized by including the step of determining the median of the two or more candidate SOH values ​​as the SOH value of the battery corresponding to the discharge period.

15. In Paragraph 11, A battery SOH estimation method characterized by further including, after the above-mentioned estimation step, a step of correcting the SOH values ​​based on a moving average, a weighted moving average, or an exponential moving average when SOH values ​​corresponding to each of a plurality of different discharge periods are estimated.

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