Battery SOH estimation device and method

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 based on 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 a device and method for estimating the SOH of a battery, and more particularly to a device and method for estimating the SOH of a battery that can more accurately estimate the SOH. [Background technology]

[0003] In recent years, as demand for portable electronic products such as laptops, video cameras, and mobile phones has grown rapidly and development of electric vehicles, energy storage batteries, robots, satellites, and other products has progressed in earnest, active research has been 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 their advantages of being able to be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and a high energy density.

[0005] The capacity of such batteries decreases depending on the usage environment, duration of use, number of charge / discharge cycles, etc. The battery's State of Health (SOH) is an index that indicates how much the battery capacity has decreased from its initial capacity, and is one of the important parameters for evaluating the battery's lifespan.

[0006] Generally, the current integration method can be used to estimate a battery's SOH. This method measures battery capacity by integrating current through full charge and full discharge, and then compares this with the initial battery capacity to estimate the battery's SOH. While this method can estimate the battery's SOH fairly accurately as long as temperature and discharge rate deviations can be properly compensated for, it is inefficient because it requires the battery to be fully charged and then fully discharged. Another drawback is that if the offset of the current sensor that measures the battery current changes due to degradation, errors accumulate in the current integration process, which can lead to inaccurate estimation results. 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 a battery SOH estimation device and method that can more accurately estimate the battery SOH by correcting the estimated battery SOH based on the battery SOC change amount, SOC (State of charge) change interval, and temperature.

[0008] Other objects and advantages of the present invention will become apparent from the following description and the embodiments of the present invention, and it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [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 resulting from the charge / discharge C rate, an SOC range factor resulting from a comparison result between the SOC change range and a predetermined 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 correction unit configured to correct the first SOH based on the calculated weighting value and a predetermined 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 that is 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 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 that include at least a portion of the SOC change interval among the SOC reference intervals, 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 the 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 the 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 estimation device according to one aspect of the present invention.

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

[0026] A battery SOH estimation method according to yet another aspect of the present invention may include an SOH estimation 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 of 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 the battery information; 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 predetermined 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 correction step of correcting the first SOH based on the calculated weighting value and a predetermined second SOH. [Effects of the Invention]

[0027] According to one embodiment of the present invention, various factors about the battery are taken into consideration, 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 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, and therefore the present invention should not be interpreted as being limited to the matters depicted in the drawings. [Brief explanation 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] [Figure 2] 1 is a schematic diagram illustrating how a battery SOH estimation device according to an embodiment of the present invention estimates the SOH of a battery;

[0032] [Figure 3] FIG. 1 is a diagram illustrating a schematic differential profile of a negative electrode of a battery.

[0033] [Figure 4] FIG. 1 is a diagram illustrating a schematic differential profile of a positive electrode of a battery.

[0034] [Figure 5] 3 is a diagram illustrating an example of an SOC interval factor table set in the battery SOH estimation device according to an embodiment of the present invention. FIG.

[0035] [Figure 6] 3 is a diagram illustrating an example of an SOC variation factor table set in the battery SOH estimation device according to an embodiment of the present invention. FIG.

[0036] [Figure 7]3 is a diagram illustrating an example of a temperature factor table set in the battery SOH estimation device according to an embodiment of the present invention. FIG.

[0037] [Figure 8] 3 is a diagram illustrating an example of a C-rate factor table set in the battery SOH estimation device according to an embodiment of the present invention. FIG.

[0038] [Figure 9] 10 is a diagram illustrating another example of a C rate factor table set in the battery SOH estimation device according to an embodiment of the present invention. FIG.

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

[0040] [Figure 11] 10 is a diagram illustrating a method for estimating the SOH of a battery according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] The terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor can appropriately define the concepts of terms himself / herself in order to best explain the invention.

[0042] Therefore, it should be understood that the embodiments 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 that 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 and second are used to distinguish one of various components from the other components, and do not limit the components.

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

[0046] Furthermore, throughout this specification, when a part is said to be "connected (coupled)" to another part, this includes not only the case where it is "directly connected (coupled)" but also the case where it is "indirectly connected (coupled)" with 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, a 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 a battery. A battery may also refer to a battery module in which multiple cells are connected in series and / or parallel. For ease of explanation, the following description will be made assuming that a battery refers to a single independent cell.

[0050] Referring to FIG. 1, a battery SOH estimation device 100 may include an SOH estimation unit 110, a C-rate estimation unit, an SOC change calculation unit 130, a weighting value calculation unit 140, and an SOH correction 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 battery voltage, current, and temperature from an external source or may store the battery information in advance. Preferably, the SOH estimation unit 110 may estimate the SOH based on battery information including all of the battery voltage, current, and temperature.

[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 relationship between the battery voltage and the SOC may be set in advance, and the SOH estimator 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 relationship between the battery voltage, temperature, and SOC. In this case, the SOH estimator 110 may estimate the SOC corresponding to the battery voltage and temperature based on the SOC profile.

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

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

[0059] The first SOH of the battery estimated by the SOH estimator 110 may be an SOH value based on the voltage and current of the battery 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 the same as 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 an 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 multiple. Preferably, the battery voltage 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. Furthermore, 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 an SOC1 corresponding to the V1 voltage and an SOC2 corresponding to the V2 voltage. The SOC change calculation unit 130 may calculate an 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 can calculate the amount of SOC change by calculating the formula "|SOC2-SOC1|." That is, the SOC change calculation unit 130 can 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 can be expressed as ΔSOC and can 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, an SOC interval factor, an SOC variation factor, and a temperature factor.

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

[0071] The SOC interval factor may be calculated depending on whether or not a preset SOC reference interval overlaps with the 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 portion of the SOC change interval belongs to the SOC reference interval. Specific embodiments for calculating the SOC interval factor will be described in detail below 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 so that it is proportional to the SOC change amount. A specific embodiment for calculating the SOC change amount factor will be described in detail later with reference to FIG. 6.

[0073] The temperature factor is 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 for calculating the temperature factor will be described in detail below 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 so as to be proportional to the calculated C rate. A specific embodiment for calculating the C rate factor will be described in detail later with reference to FIG. 8.

[0075] Furthermore, the weighting value calculation unit 140 may be configured to calculate a 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 a 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 greater than or equal to 0 and less than or equal to 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] 2, a first SOH SOH1 can be estimated based on the voltage and current of the battery, and the first SOH SOH1 is then 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 estimation unit 110 may be configured to estimate a first SOH SOH1 in the current cycle based on battery information (e.g., at least one of voltage, current, and temperature) corresponding to the current cycle.

[0084] For example, the SOH estimation unit 110 may estimate a first SOH (SOH1) in a current cycle of the battery based on the battery information, and the SOH correction unit 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 taking into account various factors such as the C rate, the SOC change interval, the SOC change amount, and the temperature.

[0087] Furthermore, the battery SOH estimation device 100 has the advantage of being able to improve the accuracy of battery SOH estimation by recursively estimating the battery SOH in the current cycle as the battery charge / discharge cycle progresses, taking into account the battery SOH estimated in the previous cycle (second SOH) and the weighted 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 (ASIC), other chipsets, logic circuits, registers, communication modems, data processing devices, etc., known in the art, to activate the various control logics performed in the present invention.

[0089] The battery SOH estimating device 100 may further include a memory unit 160. The memory unit 160 may store data and programs required for each component of the battery SOH estimating device 100 to operate and function, or data generated during the operation and function. The memory unit 160 may be any known information storage device capable of recording, erasing, updating, and reading data. For example, the information storage device 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, etc. The memory unit 160 may also store program code defining processes that can be activated by the SOH estimating unit 110, the C-rate calculating unit 120, the SOC change calculating unit 130, the weighting value calculating unit 140, and the SOH correcting 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 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 multiple SOC intervals, and the weighting value calculation section 140 may be configured to calculate the SOC interval factor depending on whether at least a portion of the SOC change interval belongs to each of the multiple SOC intervals.

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

[0094] The differential profiles of Figures 3 and 4 are preset for a battery in a BOL state and may be differential profiles that indicate the relationship between the SOC and the differential voltage dV / dSOC. 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 SOC range of 0% to 40% and the SOC range of 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 SOC range of 60% to 100%.

[0096] Therefore, multiple SOC reference intervals may be preset for each of the intrinsic stress regions of the positive and negative electrode active materials. For example, referring to Figures 3 and 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 differs, the number and size of the SOC reference intervals may differ accordingly.

[0098] 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, if all of the battery's SOC change intervals are 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 battery's SOC change intervals 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, if at least a portion of the battery's SOC change period belongs to all of the first to third SOC reference periods A, B, and C, the SOC period factor may be s3. For example, if the battery's SOC change period is SOC 30% to 80%, at least a portion of the battery's SOC change period (30% to 80%) may be included in all of the first to third SOC reference periods A, B, and C. Therefore, the SOC period factor for the battery may be set to s3.

[0103] As another example, if 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, the SOC interval factor may be s2. For example, if 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 if at least a portion of the battery's SOC change interval belongs to only one of the first to third SOC reference intervals A, B, and C. For example, if the battery's SOC change interval is 30% to 50%, at least a portion of the battery's SOC change interval (30% to 50%) 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, since the embodiment of Figure 5 is an embodiment in which three SOC reference intervals are preset, it should be noted that if the number of preset SOC reference intervals is changed, the SOC interval factor may also change accordingly. For example, assume that five SOC reference intervals are set, unlike the embodiment of Figure 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 factor 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), or s1 (the number of SOC intervals to which it belongs is 1).

[0106] Generally, during a battery charge / discharge process, the closer the battery's SOC is to the intrinsic stress region of the positive active material and / or the intrinsic stress region of the negative active material, the more accelerated the battery's degradation may be. Therefore, the battery SOH estimating device 100 according to an embodiment of the present invention has the advantage of being able to calculate an SOC range factor taking into account the accelerated battery degradation caused by the intrinsic stress region of the active materials in order to more accurately estimate the battery SOH.

[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 unit 140 may be configured to calculate the SOC variation factor so as to be proportional to the SOC variation.

[0109] Specifically, the weighting value calculation section 140 can be configured to calculate an 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, which is calculated as "|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 construed as being limited by the embodiment of FIG. 6.

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

[0113] Preferably, the SOC variation factor may be preset to be proportional to the SOC variation ΔSOC of the battery. In the embodiment of Fig. 6, the SOC variation factor may be a value obtained by converting the SOC variation ΔSOC so as to have a value between ds0 and 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-described embodiment, assume that the SOC change range of the battery is 30% to 80% SOC. 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 battery temperature 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 estimation device 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 FIG. 7, if the battery temperature is 25° C. or higher, 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 0° C. or lower, the temperature factor may be set to t0.

[0122] The temperature factor for a battery temperature not included in the temperature factor table may be calculated based on the battery temperature and 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 interpolation to calculate the temperature factors for the respective temperatures 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-rates and C-rate factors 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. 8.

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

[0129] FIG. 9 is a diagram schematically 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 C-rate factors resulting from the temperature of the battery and the charge / discharge C-rate.

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

[0132] For example, in the embodiment of Figure 9, assume that the battery temperature 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. Here, the C-rate factors may increase in value in the order of c1, c2, and c3.

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

[0134] In addition, there are cases where the value of c4 is even greater than c1, the value of c5 is even greater than c2, and the value of c6 is even 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 battery temperature, SOC change amount, SOC change interval, and charge / discharge C rate. That is, the battery SOH estimating device 100 has the advantage of being able to estimate the battery SOH more accurately by considering various factors that affect battery degradation (temperature, SOC change amount, SOC change interval, and charge / discharge C rate). In particular, the battery SOH estimating device 100 has the advantage of being able to reflect acceleration factors of battery degradation when estimating the battery SOH by considering the SOC change interval factor resulting from the intrinsic stress region of the active material.

[0136] The battery SOH estimation device 100 according to the present invention can be applied to a battery management system (BMS). That is, a BMS according to the present invention can include the battery SOH estimation device 100 described above. In such a configuration, at least some of the components of the battery SOH estimation device 100 can be realized by supplementing or adding functions of components 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] 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 schematically 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 of the battery pack 10.+ and the negative terminal of the battery 11 is connected to the negative terminal P of the battery pack 10. - and can be connected.

[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 the positive terminal of the battery 11 via a first sensing line SL1 and to the 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 on 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 that includes 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 yet 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 description of the contents that overlap 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 can 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 can calculate the charge / discharge C rate of the battery based on information about the current flowing through a charge / discharge path (for example, a large current path) of the battery.

[0153] The SOC change calculation step (S300) is a step of calculating the SOC change interval and the SOC change amount of the battery based on the voltage of the battery, and can 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 the end SOC of the battery in one cycle.

[0155] For example, if 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 of 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.

[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 interval factor due to the comparison result between the SOC change interval and a preset SOC reference interval, an SOC change amount factor due to the SOC change amount, and a temperature factor due to the measured battery temperature, and can 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. It may also calculate an SOC interval factor for the SOC change interval based on an SOC interval factor table. It may also calculate an SOC change amount factor for the SOC change amount based on an SOC change amount factor table. It may also calculate a temperature factor for the battery temperature 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 can 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 can 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 the 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 weighted value calculated in the current cycle.

[0163] The above-described embodiments of the present invention may be realized not only by the apparatus and method but also by 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 realized by a person skilled in the technical field to which the present invention pertains from 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 to these, 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 technical spirit of the present invention and the scope of equivalents of the claims.

[0165] Furthermore, the present invention described above can be variously replaced, modified, and changed by a person having ordinary knowledge in the technical field to which the present invention belongs within the scope that does not deviate from the technical concept of the present invention, and therefore is not limited to the above-described embodiments and the accompanying drawings, and can 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 unit 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 interval 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 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 a temperature of the battery; an SOH correction unit configured to correct the first SOH based on the first SOH, the calculated weighting value, and a second SOH preset before a current cycle; A battery SOH estimating device comprising:

2. 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 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 that is 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 estimating device according to claim 3 , wherein the SOH estimating device is configured to be proportional to the temperature and the charge / discharge C-rate.

5. The weighting value calculation unit The battery SOH estimation device according to claim 1 , wherein the SOC range factor is calculated depending on whether at least a portion of the SOC change range belongs to the SOC reference range.

6. The SOC reference section is provided in plurality, The weighting value calculation unit 6. The battery SOH estimation device according to claim 5, wherein the device is configured to calculate the number of SOC intervals that include 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 estimation device according to claim 1, wherein the SOC change factor corresponding to the calculated SOC change is calculated based on a preset SOC change 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 section factor, the SOC change amount factor, and the temperature factor.

10. The SOH estimation unit configured to estimate the first SOH in the current cycle based on the battery information in the current cycle; The SOH correction unit 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 The battery SOH estimating device according to claim 10 , wherein the first SOH is corrected in a cycle prior to the current cycle.

12. The SOH correction unit The first SOH is corrected using the following formula: [Formula] SOH ＭＯＤ =(SOH １ ((SOH ２ Х(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, which is equal to or greater than 0 and equal to or less than 1.

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

14. A motor vehicle comprising the battery SOH estimation device according to any one of claims 1 to 12.

15. 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 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 interval and an SOC change amount of the battery based on the information of the battery; a weighting value calculation step of calculating a weighting value based on 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 temperature of the battery; an SOH correction step of correcting the first SOH based on the first SOH, the calculated weighting value, and a second SOH preset before the current cycle; A method for estimating the SOH of a battery, comprising:

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