Apparatus and method for estimating battery SOH

Abstract

The present invention relates to an apparatus and method for estimating the state of health (SOH) of a battery, which can estimate the SOH of the battery more accurately. More specifically, the present invention aims to provide an apparatus and method for estimating the SOH of a battery, which can estimate the SOH of the battery more accurately by correcting the estimated SOH of the battery based on the SOC change amount, SOC change interval, and temperature of the battery.

Description

[Technical field]

[0001] This application claims priority to Korean Patent Application No. 10-2022-0060635, filed on May 18, 2022, and the entire contents disclosed in the specification and drawings of that application are incorporated herein by reference.

[0002] The present invention relates to an apparatus and method for estimating the SOH of a battery, and more particularly to an apparatus and method for estimating the SOH of a battery that can estimate the state of health (SOH) of a battery more accurately. [Background technology]

[0003] In recent years, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and the development of electric vehicles, energy storage batteries, robots, satellites, and other products has progressed in earnest, active research is being conducted into high-performance batteries that can be repeatedly charged and discharged.

[0004] Currently, commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Of these, lithium batteries are attracting attention due to the advantages that they can be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, as well as an extremely low self-discharge rate and high energy density.

[0005] The capacity of such batteries decreases depending on the usage environment, period of use, number of charge / discharge cycles, etc. The state of health (SOH) of a battery is an index showing how much the battery capacity has decreased from the initial battery capacity, and is one of the important parameters for evaluating the lifespan of a battery.

[0006] In general, a current integration method can be used to estimate the SOH of a battery. The current integration method estimates the SOH of a battery by measuring the battery capacity by current integration through full charging and full discharging, and comparing it with the initial battery capacity. This method can estimate the SOH of a battery quite accurately as long as the temperature and discharge rate deviation can be properly guaranteed, but it is inefficient because it is necessary to fully charge and then fully discharge the battery. In addition, if the offset changes due to deterioration of the current sensor that measures the battery current, errors are accumulated in the current integration process, which is a drawback in that the estimation result may become inaccurate. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised to solve the above problems, and aims to provide an apparatus and method for estimating the SOH of a battery, which can more accurately estimate the SOH of a battery by correcting an estimated SOH of the battery based on a battery SOC change amount, a SOC (State of charge) change interval, and a temperature.

[0008] Other objects and advantages of the present invention will be understood from the following description and will become more apparent from the embodiments of the present invention. Also, it will be easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0009] A battery SOH estimation device according to one aspect of the present invention may include an SOH estimation unit configured to estimate a first SOH of the battery based on battery information including at least one of a voltage, a current, and a temperature of the battery; a C rate calculation unit configured to calculate a charge / discharge C rate for the battery based on the battery information; an SOC change calculation unit configured to calculate an SOC change range and an SOC change amount of the battery based on the battery information; a weighting value calculation unit configured to calculate a weighting value based on at least one of a C rate factor attributable to the charge / discharge C rate, an SOC range factor attributable to a result of comparing the SOC change range with a preset SOC reference range, an SOC change amount factor attributable to the SOC change amount, and a temperature factor attributable to the temperature of the battery; and an SOH correction unit configured to correct the first SOH based on the calculated weighting value and a preset second SOH.

[0010] The weighting value calculation unit may be configured to calculate the C rate factor corresponding to the calculated charge / discharge C rate based on a C rate factor table preset to indicate a correspondence relationship between the charge / discharge C rate and the C rate factor.

[0011] The weighting value calculation unit may be configured to calculate the C-rate factor corresponding to the calculated C-rate and the temperature based on a C-rate factor table preset to indicate the C-rate factor resulting from the temperature of the battery and the charge / discharge C-rate.

[0012] The C-rate factor may be configured to be proportional to the temperature and the C-rate.

[0013] The weighting value calculation unit may be configured to calculate the SOC interval factor depending on whether or not at least a portion of the SOC change interval belongs to the SOC reference interval.

[0014] A plurality of SOC reference sections may be provided.

[0015] The weighting value calculation unit may be configured to calculate the number of SOC intervals among the SOC reference intervals that include at least a portion of the SOC change interval, and calculate the SOC interval factor corresponding to the calculated number of SOC intervals based on a preset SOC interval factor table.

[0016] The weighting value calculation unit may be configured to calculate the SOC change amount factor corresponding to the calculated SOC change amount based on a preset SOC change amount factor table.

[0017] The weighting value calculation unit may be configured to calculate the temperature factor corresponding to a temperature of the battery based on a preset temperature factor table.

[0018] The weighting value calculation unit may be configured to calculate the weighting value by multiplying the C-rate factor, the SOC interval factor, the SOC change amount factor, and the temperature factor.

[0019] The SOH estimator may be configured to estimate the first SOH in the current cycle based on the battery information in the current cycle.

[0020] The SOH correction unit may be configured to correct the first SOH based on the weighting value and the second SOH set before the current cycle.

[0021] The second SOH may be a first SOH corrected in a cycle prior to the current cycle.

[0022] The SOH correction unit may be configured to correct the first SOH using the following formula: [Formula] SOH MOD=(SOH1Хα)+(SOH2Х(1-α))

[0023] Here, SOH MOD is a corrected first SOH, SOH1 is the first SOH, SOH2 is the second SOH, and α is the weighting value, which may be greater than or equal to 0 and less than or equal to 1.

[0024] A battery pack according to another aspect of the present invention may include a battery SOH estimator according to one aspect of the present invention.

[0025] A vehicle according to yet another aspect of the present invention may include a battery SOH estimator according to one aspect of the present invention.

[0026] A battery SOH estimating method according to yet another aspect of the present invention may include an SOH estimating step of estimating a first SOH of the battery based on battery information including at least one of a voltage, a current, and a temperature of the battery; a C rate calculating step of calculating a charge / discharge C rate of the battery based on the battery information; an SOC change calculating step of calculating an SOC change range and an SOC change amount of the battery based on the battery information; a weighting value calculating step of calculating a weighting value based on at least one of a C rate factor resulting from the charge / discharge C rate, an SOC range factor resulting from a comparison result of the SOC change range with a preset SOC reference range, an SOC change amount factor resulting from the SOC change amount, and a temperature factor resulting from the temperature of the battery; and an SOH correcting step of correcting the first SOH based on the calculated weighting value and a preset second SOH. Effect of the Invention

[0027] According to an embodiment of the present invention, various factors regarding the battery are taken into account, which has the advantage that the SOH of the battery can be estimated more accurately.

[0028] The effects of the present invention are not limited to those described above, and other effects not mentioned herein will be clearly understood by those skilled in the art from the description of the claims.

[0029] The drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the above-described content of the invention, serve to further understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief description of the drawings]

[0030] [Figure 1] 1 is a diagram illustrating a battery SOH estimation device according to an embodiment of the present invention;

[0031] [Diagram 2] 1 is a schematic diagram illustrating a battery SOH estimation device according to an embodiment of the present invention estimating a battery SOH.

[0032] [Diagram 3] FIG. 2 is a schematic diagram showing a differential profile of a negative electrode of a battery.

[0033] [Figure 4] FIG. 2 is a schematic diagram showing the differential profile of the positive electrode of a battery.

[0034] [Diagram 5] 4 is a diagram illustrating an example of an SOC interval factor table set in the battery SOH estimating device according to an embodiment of the present invention. FIG.

[0035] [Figure 6] 4 is a diagram illustrating an example of an SOC change amount factor table set in the battery SOH estimating device according to an embodiment of the present invention. FIG.

[0036] [Figure 7]4 is a diagram illustrating an example of a temperature factor table set in the battery SOH estimating device according to an embodiment of the present invention. FIG.

[0037] [Figure 8] FIG. 2 is a diagram illustrating an example of a C-rate factor table set in the battery SOH estimating device according to an embodiment of the present invention.

[0038] [Figure 9] 11 is a diagram illustrating another example of a C-rate factor table set in the battery SOH estimating device according to an embodiment of the present invention. FIG.

[0039] [Figure 10] FIG. 2 is a schematic diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0040] [Figure 11] 13 is a diagram illustrating a battery SOH estimation method according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The terms and words used in this specification and the claims are not to be interpreted limited to their ordinary or dictionary meanings, but are to be interpreted in a meaning and concept corresponding to the technical idea of ​​the present invention in accordance with the principle that the inventor can appropriately define the concept of the term himself / herself in order to explain the invention in the best possible way.

[0042] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0043] Furthermore, in describing the present invention, if it is recognized that a specific description of known technology related to the present invention may obscure the gist of the present invention, the detailed description will be omitted.

[0044] Phrases including ordinal numbers such as first, second, etc. are used to distinguish one of various components from the other components, and do not limit the components.

[0045] Throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, not excluding other elements, unless otherwise specified.

[0046] In addition, throughout this specification, when it is said that a part is "connected (coupled)" to another part, this includes not only the case where it is "directly connected (coupled)" to another part, but also the case where it is "indirectly connected (coupled)" via another element in between.

[0047] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0048] FIG. 1 is a diagram illustrating a battery SOH estimation device 100 according to an embodiment of the present invention.

[0049] Here, the term "battery" refers to a single independent cell that has a negative terminal and a positive terminal and can be physically separated. As an example, a lithium ion battery or a lithium polymer battery may be considered as a battery. The term "battery" may also refer to a battery module in which a plurality of cells are connected in series and / or parallel. In the following description, for ease of explanation, it is assumed that the term "battery" refers to a single independent cell.

[0050] Referring to FIG. 1, a battery SOH estimating device 100 may include a SOH estimating unit 110, a C-rate estimating unit, a SOC change calculating unit 130, a weighting value calculating unit 140, and a SOH correcting unit 150.

[0051] The SOH estimator 110 may be configured to estimate a first SOH of the battery based on battery information including at least one of a voltage, a current, and a temperature of the battery.

[0052] For example, the SOH estimation unit 110 may receive battery information including at least one of the voltage, current, and temperature of the battery from an external source or may store the battery information in advance. Preferably, the SOH estimation unit 110 may estimate the SOH based on the battery information including all of the voltage, current, and temperature of the battery.

[0053] As another example, the SOH estimator 110 may be configured to directly measure the voltage, current, and temperature of the battery.

[0054] Specifically, the SOH estimator 110 may be configured to estimate a first SOH in the current cycle based on the battery information in the current cycle.

[0055] For example, the SOH estimator 110 may estimate a first SOH of the battery based on a change in the capacity of the battery, and may estimate a corresponding State of Charge (SOC) from the voltage of the battery.

[0056] Here, an SOC profile indicating the correspondence between the battery voltage and the SOC may be set in advance, and the SOH estimation unit 110 may estimate the corresponding SOC from the battery voltage based on the SOC profile. Alternatively, the SOC profile may be set in advance to indicate the correspondence between the battery voltage, temperature, and SOC. In this case, the SOH estimation unit 110 may estimate the SOC corresponding to the battery voltage and temperature based on the SOC profile.

[0057] Then, the SOH estimation unit 110 may calculate the capacity of the battery based on the estimated SOC and the battery current. The SOH estimation unit 110 may then estimate a first SOH of the battery by calculating a ratio between a reference capacity preset for the battery and the calculated capacity. Here, the reference capacity may be a value preset as the capacity of the battery in the beginning of life (BOL) state, and may be a capacity value corresponding to the open circuit voltage (OCV) of the battery calculated by the SOH estimation unit 110.

[0058] As another example, the SOH estimation unit 110 may estimate the first SOH of the battery based on a change in the internal resistance of the battery. The SOH estimation unit 110 may estimate the internal resistance of the battery from the voltage and current of the battery based on Ohm's law. The SOH estimation unit 110 may then estimate the first SOH of the battery by calculating a ratio between a reference resistance preset for the battery and the calculated internal resistance. Here, the reference resistance may be a value preset as the internal resistance of the battery in the BOL state.

[0059] The first SOH of the battery estimated by the SOH estimator 110 may be a SOH value based on the battery's voltage and current measured in the current cycle.

[0060] The C-rate calculation unit 120 may be configured to calculate a charge / discharge C-rate for the battery based on the battery information, where the C-rate may be an index indicating a charge / discharge rate.

[0061] For example, the C rate calculation unit 120 may receive information about the current flowing through a charge / discharge path (e.g., a large current path) of the battery from an external source. Then, the C rate calculation unit 120 may calculate the C rate from the information about the current flowing through the charge / discharge path. Here, the information about the battery current acquired by the C rate calculation unit 120 may be similar to the information about the battery current acquired by the SOH estimation unit 110.

[0062] As another example, the C rate calculation unit 120 may directly measure the charge / discharge current of the battery and calculate the C rate based on the measured charge / discharge current.

[0063] The SOC change calculation unit 130 may be configured to calculate a SOC change interval and an SOC change amount of the battery based on the battery information.

[0064] For example, the SOC change calculation unit 130 may be configured to calculate the SOC change interval and the SOC change amount of the battery based on the voltage of the battery.

[0065] Specifically, the measured battery voltage may be a plurality of voltages. Preferably, the voltage of the battery may be measured from charging and / or discharging and may include a start voltage and an end voltage. Then, the SOC change calculation unit 130 may estimate the SOC for the measured voltage (start voltage and end voltage) by referring to the SOC profile. The SOC change calculation unit 130 may calculate an SOC change interval including the estimated SOC. Also, the SOC change calculation unit 130 may calculate the difference between the estimated SOCs to calculate the SOC change amount.

[0066] For example, assume that the measured battery voltages are V1 and V2, and the battery is charged from the V1 voltage to the V2 voltage. The SOC change calculation unit 130 may estimate SOC1 corresponding to the V1 voltage and SOC2 corresponding to the V2 voltage. The SOC change calculation unit 130 may calculate the SOC change interval including SOC1 and SOC2 by setting the start SOC and end SOC of the SOC change interval to SOC1 and SOC2, respectively.

[0067] Furthermore, the SOC change calculation unit 130 may calculate the amount of SOC change by calculating the formula "|SOC2-SOC1|". That is, the SOC change calculation unit 130 may calculate the amount of SOC change by calculating the absolute value of the SOC deviation between SOC2 and SOC1. Here, the amount of SOC change may be written as ΔSOC, and may be calculated as a value greater than or equal to 0% and less than or equal to 100%.

[0068] The weighting value calculation unit 140 may be configured to calculate the weighting value based on at least one of a C-rate factor resulting from the charge / discharge C-rate, an SOC interval factor resulting from a comparison result between the SOC change interval and a preset SOC reference interval, an SOC change amount factor resulting from the SOC change amount, and a temperature factor resulting from the measured battery temperature.

[0069] The weighting value calculation unit 140 may be configured to calculate a C-rate factor, a SOC interval factor, a SOC change amount factor, and a temperature factor.

[0070] For example, the weighting value calculation unit 140 may receive the temperature of the battery from an external source or may store the temperature of the battery in advance, or the weighting value calculation unit 140 may be configured to directly measure the temperature of the battery.

[0071] The SOC interval factor may be calculated depending on whether or not there is an overlap between a preset SOC reference interval and a SOC change interval calculated by the SOC change calculation unit 130. For example, the weighting value calculation unit may calculate the SOC interval factor depending on whether or not at least a part of the SOC change interval belongs to the SOC reference interval. A specific embodiment in which the SOC interval factor is calculated will be described in detail later with reference to FIGS. 3 to 5.

[0072] The SOC change amount factor is a factor calculated based on the SOC change amount calculated by the SOC change calculation unit 130. For example, the weighting value calculation unit 140 may calculate the SOC change amount factor to be proportional to the SOC change amount. A specific embodiment in which the SOC change amount factor is calculated will be described in detail later with reference to FIG. 6.

[0073] The temperature factor is a factor calculated based on the temperature of the battery. For example, the weighting value calculation unit 140 may calculate the temperature factor to be proportional to the temperature of the battery. A specific embodiment in which the temperature factor is calculated will be described in detail later with reference to FIG. 7.

[0074] The C rate factor is a factor calculated based on the C rate calculated by the C rate calculation unit 120. For example, the weighting value calculation unit 140 may calculate the C rate factor to be proportional to the calculated C rate. A specific embodiment in which the C rate factor is calculated will be described in detail later with reference to FIG.

[0075] Furthermore, the weighting value calculation unit 140 may be configured to calculate the weighting value based on a C rate factor, an SOC interval factor, an SOC change amount factor, and a temperature factor. For example, the weighting value calculation unit 140 may be configured to calculate the weighting value by multiplying the C rate factor, the SOC interval factor, the SOC change amount factor, and the temperature factor. Here, the weighting value calculated by the weighting value calculation unit 140 may be set to have a value equal to or greater than 0 and equal to or less than 1.

[0076] The SOH estimation device may be configured to correct the first SOH based on the calculated weighting value and a preset second SOH.

[0077] Specifically, the SOH correction unit 150 may be configured to correct the first SOH based on the weighting value and the second SOH set before the current cycle. That is, the first SOH estimated by the SOH estimation unit 110 based on the battery information may be corrected by the SOH correction unit 150 based on the weighting value and the second SOH.

[0078] FIG. 2 is a schematic diagram illustrating how the battery SOH estimation device 100 according to one embodiment of the present invention estimates the SOH of a battery.

[0079] Referring to FIG. 2, a first SOH SOH1 can be estimated based on the voltage and current of the battery. Then, the first SOH SOH1 is corrected based on the second SOH SOH2 and the weighting value α to obtain the corrected first SOH SOH MOD can be calculated.

[0080] For example, the SOH correction unit 150 may be configured to correct the first SOH using the following formula: [Formula] SOH MOD =(SOH1Хα)+(SOH2Х(1-α))

[0081] Here, SOH MOD is the corrected first SOH, SOH1 is the first SOH, SOH2 is the second SOH, and α is a weighting value, which can be greater than or equal to 0 and less than or equal to 1.

[0082] In the embodiment based on the above formula, the SOH correction unit 150 may multiply the first SOH SOH1 by the weighting value α and multiply the second SOH SOH2 by the complement 1-α of the weighting value α. Then, the SOH correction unit 150 adds the first SOH SOH1 multiplied by the weighting value α and the second SOH SOH2 multiplied by the complement 1-α to obtain the corrected first SOH SOH MOD can be calculated.

[0083] Further referring to FIG. 2, the SOH estimator 110 may be configured to estimate a first SOH SOH1 in the current cycle based on battery information (e.g., at least one of a voltage, a current, and a temperature) corresponding to the current cycle.

[0084] For example, the SOH estimator 110 may estimate a first SOH SOH1 in a current cycle of the battery based on the battery information, and the SOH corrector 150 may be configured to correct the first SOH SOH1 based on the weighting value α and a second SOH SOH2 preset before the current cycle.

[0085] Also, referring to FIG. 2, the second SOH SOH2 is the first SOH SOH corrected in the cycle before the current cycle. MOD That is, the corrected SOH calculated in the current cycle SOH MOD can be used as the second SOH SOH2 in the next cycle.

[0086] The battery SOH estimating device 100 according to an embodiment of the present invention has an advantage in that it can estimate the battery SOH more accurately by considering various factors such as C rate, SOC change interval, SOC change amount, and temperature.

[0087] Furthermore, the battery SOH estimation device 100 has the advantage that, as the battery charge / discharge cycle progresses, the battery SOH estimation device 100 can improve the accuracy of the battery SOH estimation by recursively estimating the battery SOH in the current cycle by taking into account the battery SOH estimated in the previous cycle (second SOH) and the weighting value calculated in the current cycle.

[0088] Meanwhile, the SOH estimation unit 110, C-rate calculation unit 120, SOC change calculation unit 130, weighting value calculation unit 140 and SOH correction unit 150 provided in the battery SOH estimation device 100 may selectively include a processor, application specific integrated circuits (ASICs), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art to activate various control logics performed in the present invention.

[0089] The battery SOH estimation device 100 may further include a storage unit 160. The storage unit 160 may store data and programs required for each component of the battery SOH estimation device 100 to operate and function, or data generated in the process of operating and functioning. The storage unit 160 is not particularly limited in type as long as it is a known information storage means known to be capable of recording, erasing, updating, and reading data. As an example, the information storage means may include a random access memory (RAM), a flash memory, a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a register, and the like. The storage unit 160 may store program code that defines processes that can be activated by the SOH estimation unit 110, the C-rate calculation unit 120, the SOC change calculation unit 130, the weighting value calculation unit 140, and the SOH correction unit 150.

[0090] In the following, an embodiment will be described in which the SOC interval factor is calculated based on the SOC change interval.

[0091] The weighting value calculation unit 140 may be configured to calculate the SOC interval factor depending on whether or not at least a portion of the SOC change interval belongs to the SOC reference interval.

[0092] Preferably, the SOC reference interval may be configured to include a plurality of SOC intervals, and the weighting value calculation section 140 may be configured to calculate the SOC interval factor depending on whether or not at least a portion of the SOC change interval belongs to each of the plurality of SOC intervals.

[0093] Figure 3 is a schematic diagram showing a differential profile of the negative electrode of a battery, and Figure 4 is a schematic diagram showing a differential profile of the positive electrode of a battery.

[0094] The differential profiles in Fig. 3 and Fig. 4 are preset for a battery in a BOL state, and may be differential profiles showing the relationship between the differential voltage dV / dSOC and the SOC. Specifically, the differential voltage may be the instantaneous rate of change of voltage (V) with respect to the SOC. The differential profile may be represented by an XY graph where X is the SOC and Y is the differential voltage dV / dSOC.

[0095] In the differential profile of the negative electrode of the embodiment in Fig. 3, the intrinsic stress region of the negative electrode active material may appear in the section of SOC 0% to 40% and the section of SOC 70% to 100%. In the differential profile of the positive electrode of the embodiment in Fig. 4, the intrinsic stress region of the positive electrode active material may appear in the section of SOC 60% to 100%.

[0096] Therefore, a plurality of SOC reference intervals may be preset for each of the inherent stress regions of the positive and negative active materials. For example, referring to Fig. 3 and Fig. 4, a first SOC reference interval A may be set to an interval of 0% to 40% SOC, a second SOC reference interval B may be set to an interval of 70% to 100% SOC, and a third SOC reference interval C may be set to an interval of 60% to 100% SOC.

[0097] However, in the embodiments of FIGS. 3 and 4, a total of three SOC reference intervals are set for the battery. However, it should be noted that if the composition of the active material of the battery is different, the number and size of the SOC reference intervals may be different accordingly.

[0098] Then, the weighting value calculation section 140 may be configured to calculate the number of SOC reference intervals that include at least a portion of the SOC change interval among the multiple SOC intervals, and calculate the SOC interval factor according to the calculated number.

[0099] 5 is a diagram illustrating an example of an SOC interval factor table set in the battery SOH estimating device 100 according to an embodiment of the present invention. The number of SOC reference intervals and SOC interval factors included in the embodiment of FIG. 5 are merely examples, and the present invention should not be construed as being limited by the embodiment of FIG. 5.

[0100] Specifically, the SOC interval factor table of FIG. 5 may be a look-up table in which SOC interval factors are preset according to the number of SOC reference intervals to which at least a portion of the SOC change interval of the battery belongs.

[0101] For example, the SOC interval factor may be set to a value greater than or equal to 0 and less than or equal to 1. Preferably, when the SOC change intervals of the battery are all included in the SOC reference interval, the SOC interval factor may be set to 1. The remaining SOC interval factors may be set according to the number of SOC reference intervals in which the SOC change intervals of the battery are included. For example, in the embodiment of FIG. 5, s3, s2, and s1 may be set to 1, 0.66, and 0.33, respectively.

[0102] For example, the SOC interval factor may be s3 when at least a portion of the battery's SOC change interval belongs to all of the first to third SOC reference intervals A, B, and C. For example, when the battery's SOC change interval is SOC 30% to 80%, at least a portion of the battery's SOC change interval (30% to 80%) may be included in all of the first to third SOC reference intervals A, B, and C. Therefore, the SOC interval factor for the battery may be set to s3.

[0103] As another example, the SOC interval factor may be s2 when at least a portion of the battery's SOC change interval belongs to only two of the first to third SOC reference intervals A, B, and C. For example, when the battery's SOC change interval is 50% to 80%, at least a portion of the battery's SOC change interval (50% to 80%) may be included in the second and third SOC reference intervals B and C. Therefore, the SOC interval factor for the battery may be set to s2.

[0104] As yet another example, the SOC interval factor may be s1 when at least a portion of the SOC change interval of the battery belongs to only one of the first to third SOC reference intervals A, B, and C. For example, when the SOC change interval of the battery is 30% to 50%, at least a portion of the SOC change interval (30% to 50%) of the battery may be included in the first SOC reference interval A. Therefore, the SOC interval factor for the battery may be set to s1.

[0105] However, it should be noted that since the embodiment of Fig. 5 is an embodiment in which the number of preset SOC reference intervals is three, if the number of preset SOC reference intervals is different, the SOC interval factor may also be different accordingly. For example, assume that the number of SOC reference intervals is set to five, unlike the embodiment of Fig. 5. In this case, the number of SOC intervals to which at least a portion of the SOC change interval belongs may be 5, 4, 3, 2, or 1. The SOC interval factors may be preset to s5 (the number of SOC intervals to which it belongs is 5), s4 (the number of SOC intervals to which it belongs is 4), s3 (the number of SOC intervals to which it belongs is 3), s2 (the number of SOC intervals to which it belongs is 2), and s1 (the number of SOC intervals to which it belongs is 1).

[0106] In general, during the charge and discharge process of a battery, the more the SOC of the battery is included in the inherent stress region of the positive active material and / or the inherent stress region of the negative active material, the more accelerated the deterioration of the battery may be. Therefore, the battery SOH estimating device 100 according to an embodiment of the present invention has an advantage that it can calculate the SOC interval factor taking into account the accelerated deterioration of the battery caused by the inherent stress region of the active material in order to estimate the battery SOH more accurately.

[0107] In the following, an embodiment will be described in which the SOC change factor is calculated based on the SOC change.

[0108] The weighting value calculation section 140 may be configured to calculate the SOC change amount factor to be proportional to the SOC change amount.

[0109] Specifically, the weighting value calculation section 140 can be configured to calculate a SOC change amount factor corresponding to the calculated SOC change amount, based on a preset SOC change amount factor table.

[0110] Here, the SOC change is the difference between the start SOC and the end SOC of the battery in one cycle, and is calculated by "|end SOC-start SOC|", and can be expressed as ΔSOC, where "|x|" means the absolute value of x.

[0111] 6 is a diagram illustrating an example of an SOC variation factor table set in the battery SOH estimating device 100 according to an embodiment of the present invention. The SOC variation and SOC variation factor included in the embodiment of FIG. 6 are merely examples, and the present invention should not be interpreted as being limited by the embodiment of FIG.

[0112] Specifically, the SOC change amount factor table of FIG. 6 may be a lookup table in which SOC change amount factors are preset according to the SOC change amount of the battery.

[0113] Preferably, the SOC change factor may be preset to be proportional to the SOC change amount ΔSOC of the battery. In the embodiment of Fig. 6, the SOC change factor may be a value obtained by converting the SOC change amount ΔSOC to have a value of ds0 to ds100. For example, ds0 may correspond to 0, ds50 may correspond to 0.5, and ds100 may correspond to 1.

[0114] For example, as in the above embodiment, assume that the SOC change section of the battery is SOC 30% to 80%. In this case, the SOC change amount ΔSOC may be 50%. Therefore, based on the SOC change amount factor table of FIG. 6, the SOC change amount factor for the battery may be set to ds50 (e.g., 0.5).

[0115] In the following, an embodiment will be described in which the temperature factor is calculated based on the temperature of the battery.

[0116] The weighting value calculation unit 140 may be configured to calculate a temperature factor according to a range to which the temperature of the battery belongs, among a plurality of preset temperature ranges.

[0117] Specifically, the weighting value calculation unit 140 may be configured to calculate a temperature factor corresponding to the temperature of the battery based on a preset temperature factor table.

[0118] Here, the temperature of the battery may be the average temperature or the maximum temperature of the battery in one cycle.

[0119] 7 is a diagram illustrating an example of a temperature factor table set in the battery SOH estimating apparatus 100 according to an embodiment of the present invention. The temperatures and temperature factors included in the embodiment of FIG. 7 are merely examples, and the present invention should not be interpreted as being limited by the embodiment of FIG.

[0120] 7 may be a lookup table in which temperature factors are preset according to the temperature of the battery. The temperature factors may be preset to be proportional to the temperature of the battery. For example, the temperature factors may be values ​​obtained by converting the temperature of the battery to have values ​​t0 to t25.

[0121] For example, in the embodiment of Figure 7, if the battery temperature is above 25°C, the temperature factor may be set to t25. If the battery temperature is 15°C, the temperature factor may be set to t15. If the battery temperature is below 0°C, the temperature factor may be set to t0.

[0122] A temperature factor for a battery temperature not included in the temperature factor table may be calculated based on the battery temperature and the temperature factor included in the temperature factor table. For example, the weighting value calculation unit 140 may calculate a temperature factor corresponding to a battery temperature not included in the temperature factor table by applying a method such as interpolation to the temperature factor table.

[0123] 7, assume that t0, t15, and t25 are 0, 0.5, and 1, respectively. If the battery temperatures are 3° C., 6° C., 9° C., 12° C., 18° C., 21° C., and 24° C., which are not included in the temperature factor table, the weighting value calculation unit 140 may use an interpolation method to calculate the temperature factors for each temperature as 0.1, 0.2, 0.3, 0.4, 0.8, and 0.95.

[0124] In the following, an embodiment will be described in which the C-rate factor is calculated based on the charge / discharge C-rate.

[0125] The weighting value calculation unit 140 may be configured to calculate a C rate factor corresponding to the calculated charge / discharge C rate based on a C rate factor table that is preset to indicate the correspondence relationship between the charge / discharge C rate and the C rate factor.

[0126] 8 is a diagram illustrating an example of a C-rate factor table set in the battery SOH estimation device 100 according to an embodiment of the present invention. The C-rate and C-rate factor included in the embodiment of FIG. 8 are merely examples, and the present invention should not be interpreted as being limited by the embodiment of FIG.

[0127] In the embodiment of FIG. 8, if the C rate is less than or equal to 0.5C, the C rate factor may be set to c1. If the C rate is greater than 0.5C and less than 4C, the C rate factor may be set to correspond to the respective C rate. If the C rate is greater than or equal to 4C, the C rate factor may be set to c3. For example, in the embodiment of FIG. 8, the C rate factor corresponding to 1C may be set to c2.

[0128] As another example, the C-rate factor may be set to correspond to a C-rate interval to which the charge / discharge C-rate of the battery belongs. For example, in the embodiment of FIG. 8, if the C-rate is less than or equal to 0.5C, the C-rate factor may be set to c1. If the C-rate is greater than 0.5C and less than or equal to 1C, the C-rate factor may be set to c2. If the C-rate is greater than or equal to 4C, the C-rate factor may be set to c3.

[0129] FIG. 9 is a diagram illustrating another example of a C-rate factor table set in the battery SOH estimating apparatus 100 according to an embodiment of the present invention.

[0130] The weighting value calculation unit 140 may be configured to calculate a C-rate factor corresponding to the calculated C-rate and temperature based on a C-rate factor table preset to indicate a C-rate factor resulting from the temperature of the battery and the charge / discharge C-rate.

[0131] That is, the C-rate factor table may be configured to indicate a C-rate factor resulting from the temperature and charge / discharge C-rate of the battery. Specifically, the C-rate factor may be configured to be proportional to the temperature and the C-rate.

[0132] For example, in the embodiment of Figure 9, assume that the temperature of the battery is 10°C. When the charge / discharge C-rate is less than 0.5C, 1C, and greater than 4C, the C-rate factors may be c1, c2, and c3, respectively, where the C-rate factors may increase in value from c1 to c2 and c3.

[0133] As another example, in the embodiment of Figure 9, assume that the temperature of the battery is 15°C. When the charge / discharge C-rate is less than 0.5C, greater than 1C, and greater than 4C, the C-rate factors may be c4, c5, and c6, respectively, where the C-rate factors may increase in value from c4 to c5 and c6.

[0134] In addition, there are cases where the value of c4 is greater than c1, the value of c5 is greater than c2, and the value of c6 is greater than c3.

[0135] The battery SOH estimating device 100 according to an embodiment of the present invention may calculate a weighting value based on the temperature, SOC change amount, SOC change interval, and charge / discharge C rate of the battery. That is, the battery SOH estimating device 100 has an advantage of being able to estimate the SOH of the battery more accurately by considering various factors (temperature, SOC change amount, SOC change interval, and charge / discharge C rate) that affect the deterioration of the battery. In particular, the battery SOH estimating device 100 has an advantage of being able to reflect an acceleration factor of battery deterioration when estimating the SOH of the battery by considering an SOC change interval factor caused by an inherent stress region of the active material.

[0136] The battery SOH estimation device 100 according to the present invention is applicable to a battery management system (BMS). That is, the BMS according to the present invention may include the battery SOH estimation device 100 described above. In such a configuration, at least a part of the components of the battery SOH estimation device 100 can be realized by complementing or adding functions of components that have been included in a conventional BMS. For example, the SOH estimation unit 110, C-rate calculation unit 120, SOC change calculation unit 130, weighting value calculation unit 140, SOH correction unit 150, and storage unit 160 of the battery SOH estimation device 100 can be realized as components of a BMS.

[0137] Furthermore, the battery SOH estimation device 100 according to the present invention may be installed in a battery pack. That is, the battery pack according to the present invention may include the above-described battery SOH estimation device 100 and one or more battery cells. The battery pack may further include electrical components (relays, fuses, etc.), a case, etc.

[0138] FIG. 10 is a diagram illustrating an exemplary configuration of a battery pack according to another embodiment of the present invention.

[0139] The positive terminal of the battery 11 is connected to the positive terminal P+ and the negative terminal of the battery 11 is connected to the negative terminal P - and

[0140] The measurement unit 12 can be connected to a first sensing line SL1, a second sensing line SL2, a third sensing line SL3, and a fourth sensing line SL4.

[0141] Specifically, the measurement unit 12 may be connected to a positive terminal of the battery 11 via a first sensing line SL1 and to a negative terminal of the battery 11 via a second sensing line SL2. The measurement unit 12 may measure the voltage of the battery 11 based on the voltage of the battery at each of the first sensing line SL1 and the second sensing line SL2.

[0142] The measurement unit 12 may be connected to the current measurement unit 13 via a third sensing line SL3. For example, the current measurement unit 13 may be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery 11. The measurement unit 12 may measure the charging current of the battery 11 via the third sensing line SL3 to calculate the charging amount. The measurement unit 12 may measure the discharging current of the battery 11 via the third sensing line SL3 to calculate the discharging amount.

[0143] In addition, the measurement unit 12 can measure the temperature of the battery 11 via a fourth sensing line SL4.

[0144] The voltage, current, and temperature of the battery 11 measured by the measurement unit 12 may be transmitted to the battery SOH estimation device 100. The battery SOH estimation device 100 may estimate the SOH of the battery 11 based on the voltage, current, and temperature of the battery 11 received from the measurement unit 12. The battery SOH estimation device 100 may calculate the charge / discharge C rate of the battery 11 based on the current of the battery 11 received from the measurement unit 12.

[0145] Furthermore, the battery SOH estimation device 100 according to the present invention may be installed in a vehicle. More specifically, the vehicle may be an electric vehicle that receives operating power from a battery pack. The vehicle may include a battery pack including the battery SOH estimation device 100.

[0146] For example, during the charging and discharging (driving) process of a vehicle, the battery SOH estimation device 100 has the advantage of being able to estimate the battery SOH more accurately by taking into account various factors that affect battery deterioration (temperature, SOC change amount, SOC change interval, and charge / discharge C rate).

[0147] FIG. 11 is a diagram illustrating a method for estimating the SOH of a battery according to still another embodiment of the present invention.

[0148] Preferably, each step of the battery SOH estimation method may be performed by the battery SOH estimation device 100. In the following, for ease of explanation, the explanation of the contents overlapping with the contents described above will be omitted or simplified.

[0149] Referring to FIG. 11, the SOH estimation method may include an SOH estimation step (S100), a C-rate calculation step (S200), an SOC change calculation step (S300), a weighting value calculation step (S400), and an SOH correction step (S500).

[0150] The SOH estimation step (S100) is a step of estimating a first SOH of the battery based on battery information including at least one of the voltage, current, and temperature of the battery, and may be performed by the SOH estimation unit 110.

[0151] The C rate calculation step (S200) is a step of calculating a charge / discharge C rate for the battery based on the battery information, and can be performed by the C rate calculation unit 120.

[0152] For example, the C rate calculation unit 120 may calculate the charge / discharge C rate of the battery based on information about the current flowing through a charge / discharge path (eg, a large current path) of the battery.

[0153] The SOC change calculation step (S300) is a step of calculating an SOC change interval and an SOC change amount of the battery based on the voltage of the battery, and may be performed by the SOC change calculation unit 130.

[0154] The SOC change calculation unit 130 may calculate an SOC change interval and an SOC change amount between the start SOC and end SOC of the battery in one cycle.

[0155] For example, when the battery is charged from SOC 30% to SOC 80%, the SOC change calculation unit 130 may calculate the SOC change amount as 50% and the SOC change range as SOC 30% to 80%.

[0156] For ease of explanation, the embodiment of Fig. 10 shows that the SOH estimation step (S100) is followed by the C rate calculation step (S200) and the SOC change calculation step (S300) in this order, but it should be noted that the order between the SOH estimation step (S100), the C rate calculation step (S200), and the SOC change calculation step (S300) is not limited in any way by the embodiment of Fig. 10. For example, the SOH estimation step (S100), the C rate calculation step (S200), and the SOC change calculation step (S300) may be performed independently of each other.

[0157] The weighting value calculation step (S400) is a step of calculating a weighting value based on at least one of a C rate factor due to the charge / discharge C rate, an SOC range factor due to a comparison result between the SOC change range and a preset SOC reference range, an SOC change amount factor due to the SOC change amount, and a temperature factor due to the measured battery temperature, and may be performed by the weighting value calculation unit 140.

[0158] For example, the weighting value calculation unit 140 may calculate a C rate factor for the calculated charge / discharge C rate based on a C rate factor table. Also, the weighting value calculation unit 140 may calculate an SOC interval factor for the SOC change interval based on an SOC interval factor table. Furthermore, the weighting value calculation unit 140 may calculate an SOC change amount factor for the SOC change amount based on an SOC change amount factor table. Furthermore, the weighting value calculation unit 140 may calculate a temperature factor for the temperature of the battery based on a temperature factor table. Then, the weighting value calculation unit 140 may calculate a weighting value by multiplying the calculated C rate factor, SOC interval factor, SOC change amount factor, and temperature factor.

[0159] The SOH correction step (S500) is a step of correcting the first SOH based on the calculated weighting value and a preset second SOH, and may be performed by the SOH correction unit 150.

[0160] For example, the SOH correction unit 150 may correct the first SOH by adding a value obtained by multiplying the first SOH by the weighting value α and a value obtained by multiplying the second SOH by the complement of the weighting value 1-α.

[0161] The method for estimating the SOH of a battery according to an embodiment of the present invention has an advantage in that it is possible to estimate the SOH of a battery more accurately by taking into account various factors such as the C rate, the SOC change interval, the SOC change amount, and the temperature.

[0162] In addition, the battery SOH estimation method has an advantage that, as the battery charge / discharge cycle progresses, the accuracy of the battery SOH estimation can be improved by recursively estimating the battery SOH in the current cycle by taking into account the battery SOH estimated in the previous cycle and the weighting value calculated in the current cycle.

[0163] The above-described embodiments of the present invention are not limited to devices and methods, but may also be realized through a program that realizes the functions corresponding to the configurations of the embodiments of the present invention or a recording medium on which the program is recorded. Such realization can be easily achieved by a person skilled in the technical field to which the present invention pertains, based on the description of the above-described embodiments.

[0164] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical concept of the present invention and the scope of the claims.

[0165] Furthermore, the present invention described above may be variously replaced, modified, and altered by a person having ordinary knowledge in the technical field to which the present invention pertains, without departing from the technical spirit of the present invention. Therefore, the present invention is not limited to the above-described embodiments and the accompanying drawings, and may be configured by selectively combining all or part of each embodiment so that various modifications can be made. [Explanation of symbols]

[0166] 10: Battery pack 11: Battery 12: Measuring part 13: Current measurement unit 100: Battery SOH Estimator 110:SOH estimation department 120: C rate calculation section 130: SOC change calculation unit 140: Weighting value calculation unit 150:SOH correction section 160: Storage section

Claims

1. a SOH estimator configured to estimate a first SOH of the battery based on battery information including at least one of a voltage, a current, and a temperature of the battery; a C-rate calculation unit configured to calculate a charge / discharge C-rate for the battery based on the battery information; an SOC change calculation unit configured to calculate an SOC change range and an SOC change amount of the battery based on the battery information; a weighting value calculation unit configured to calculate a weighting value based on at least one of a C rate factor resulting from the charge / discharge C rate, an SOC range factor resulting from a comparison result between the SOC change range and a preset SOC reference range, an SOC change amount factor resulting from the SOC change amount, and a temperature factor resulting from a temperature of the battery; an SOH correction unit configured to correct the first SOH based on the calculated weighting value and a preset second SOH; A battery SOH estimating device comprising:

2. The weighting value calculation unit 2. The battery SOH estimating device according to claim 1, configured to calculate the C rate factor corresponding to the calculated charge / discharge C rate based on a C rate factor table that is preset to indicate a correspondence relationship between the charge / discharge C rate and the C rate factor.

3. The weighting value calculation unit 2. The battery SOH estimation device according to claim 1, configured to calculate the C-rate factor corresponding to the calculated charge / discharge C-rate and the temperature, based on a C-rate factor table preset to indicate the C-rate factor resulting from the temperature of the battery and the charge / discharge C-rate.

4. The C rate factor is The battery SOH estimator of claim 3 , configured to be proportional to the temperature and the charge / discharge C-rate.

5. The weighting value calculation unit The battery SOH estimating device according to claim 1 , configured to calculate the SOC range factor depending on whether or not at least a portion of the SOC change range belongs to the SOC reference range.

6. The SOC reference section is provided in a plurality of sections, The weighting value calculation unit 6. The battery SOH estimating device according to claim 5, configured to calculate a number of SOC intervals including at least a portion of the SOC change interval among the SOC reference intervals, and to calculate the SOC interval factor corresponding to the calculated number of SOC intervals based on a preset SOC interval factor table.

7. The weighting value calculation unit 2 . The battery SOH estimating device according to claim 1 , configured to calculate the SOC change amount factor corresponding to the calculated SOC change amount based on a preset SOC change amount factor table.

8. The weighting value calculation unit The battery SOH estimating device according to claim 1 , configured to calculate the temperature factor corresponding to the temperature of the battery based on a preset temperature factor table.

9. The weighting value calculation unit The battery SOH estimating device according to claim 1 , configured to calculate the weighting value by multiplying the C-rate factor, the SOC interval factor, the SOC change amount factor, and the temperature factor.

10. The SOH estimation unit is configured to estimate the first SOH in the current cycle based on the battery information in the current cycle; The SOH correction unit includes: The battery SOH estimating device according to claim 1 , configured to correct the first SOH based on the weighting value and the second SOH set before the current cycle.

11. The second SOH is 11. The battery SOH estimator of claim 10, wherein the first SOH is corrected in a cycle prior to the current cycle.

12. The SOH correction unit includes: and configured to correct the first SOH using the following formula: [Formula] SOH ＭＯＤ =(SOH １ (Hα))+(SOH ２ (H(1-α)) Here, SOH ＭＯＤ is the corrected first SOH, and SOH １ is the first SOH to be corrected, and SOH ２ The battery SOH estimation device according to claim 10 , wherein: α is the second SOH, and α is the weighting value that is equal to or greater than 0 and equal to or less than 1.

13. A battery pack comprising the battery SOH estimator according to any one of claims 1 to 12.

14. A vehicle comprising a battery SOH estimating device according to any one of claims 1 to 12.

15. a SOH estimating step of estimating a first SOH of the battery based on battery information including at least one of a voltage, a current, and a temperature of the battery; a C rate calculation step of calculating a charge / discharge C rate for the battery based on the battery information; an SOC change calculation step of calculating an SOC change range and an SOC change amount of the battery based on information of the battery; a weighting value calculation step of calculating a weighting value based on at least one of a C rate factor resulting from the charge / discharge C rate, an SOC range factor resulting from a comparison result between the SOC change range and a preset SOC reference range, an SOC change amount factor resulting from the SOC change amount, and a temperature factor resulting from a temperature of the battery; a SOH correction step of correcting the first SOH based on the calculated weighting value and a preset second SOH; A method for estimating the SOH of a battery, comprising:

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