This application claims the benefit under 35 USC 119(a) of Korean Patent Application No. 10-2015-0010058 filed on Jan. 21, 2015, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.
1. Field
The following description relates to a method and apparatus estimating a state of a battery.
2. Description of Related Art
As environmental concerns and energy resource issues become more important, an electric vehicle (EV) has been highlighted as a vehicle of the future. The EV may not emit exhaust fumes, and may produce less noise, than a gasoline based vehicle. In such an EV, a battery may be formed in a single pack with a plurality of rechargeable and dischargeable secondary cells and even used as a main power source for the EV.
Thus, in such an EV, the battery may operate as a fuel tank would for an engine of a gasoline powered vehicle. Thus, to enhance a safety of a user of the EV, checking a state of the battery may be important.
Recently, research is being conducted to increase a convenience of a user while more accurately monitoring a state of a battery.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is the Summary intended to be used as an aid in determining the scope of the claimed subject matter.
One or more embodiments provide a battery life estimation apparatus including a stress pattern extractor configured to use at least one processing device to extract a stress pattern from sensing data acquired for a battery, the stress pattern representing changes in states of the battery based on stresses applied to the battery and characterized by categorizing different stresses represented in the sensing data, and a life estimator configured to use at least one processing device to estimate a life of the battery based on the characterized stress pattern.
The apparatus may further include a sensor system including a plurality of sensors to measure the sensing data of the battery, the sensing data being real time measurements of physical properties of the battery.
The life estimator may estimate the life of the battery in real time by providing characteristic data, as the categorized different stresses, to a learner to which a learning parameter is applied, wherein the learning parameter is previously trained on battery training sensing data of a previous time.
The sensing data may include at least one of voltage data, current data, and temperature data of the battery sensed from respective sensors configured to measure corresponding properties of the battery.
The stress pattern extractor may be configured to extract the stress pattern from the sensing data using a rainflow counting scheme, and the stress pattern may represent a plurality of cycles that respectively represent changes in values of the sensing data over time.
The stress pattern extractor may be configured to perform the categorizing by extracting a level for each of the plurality of cycles from a plurality of levels of a determined parameter, and configured to generate, based on each of the levels, characteristic data representing a characteristic of the stress pattern.
The stress pattern extractor may be configured to perform the categorizing by generating the characteristic data based on a determined number of cycles, of the plurality of cycles, that correspond to each of the plurality of levels.
The determined parameter may include at least one of an offset, an amplitude, and a period of each of the plurality of cycles.
The stress pattern extractor may be configured to create a plurality of combination parameters, each representing respective levels for each of a plurality of the determined parameters for a cycle, and configured to perform the categorizing by generating the characteristic data based on a determined number of cycles, of the plurality of cycles, whose determined parameters correspond to each of the plurality of combination parameters.
The stress pattern extractor may be configured to determine the number of cycles by applying different weights to different cycle patterns of the plurality of cycles. The different cycle patterns may include full and half cycle patterns.
The apparatus may further include a dimension transformer configured to reduce a dimension of the characteristic data, wherein the life estimator is configured to estimate the life of the battery by inputting the characteristic data with the reduced dimension to a predetermined learner to which a predetermined learning parameter is applied.
The stress pattern extractor may be configured to generate the characteristic data at a predetermined period, so that characteristic data is generated for plural predetermined periods.
The life estimator may be configured to estimate the life of the battery by inputting the characteristic data to a predetermined learner to which a predetermined learning parameter is applied.
The apparatus may include a communication interface, wherein the life estimator is configured to receive the predetermined learning parameter from an external apparatus using the communication interface, and configured to apply the received learning parameter to the predetermined learner.
The apparatus may include a storage configured to store in advance the predetermined learning parameter, wherein the life estimator is configured to obtain the predetermined learning parameter from the storage and apply the obtained predetermined learning parameter to the predetermined learner.
The life estimator may estimate the life of the battery in real time by providing characteristic data, as the categorized different stresses, to a learner to which a learning parameter is applied, and wherein the learning parameter is trained on battery training sensing data of a previous time, where the life estimation apparatus may further include a training data acquirer configured to acquire the battery training sensing data for the battery, in the previous time, a training stress pattern extractor configured to use at least one processing device to extract a training stress pattern from the battery training sensing data, the training stress pattern representing changes in states of the battery based on stresses applied to the battery and characterized by categorizing different stresses represented in the training data, and a learning parameter determiner configured to use at least one processing device to determine the learning parameter based on the characterized training stress pattern.
One or more embodiments provide a battery life estimation apparatus including a training stress pattern extractor configured to use at least one processing device to extract a training stress pattern from training data for a battery, the training stress pattern representing change in states of the battery based on stresses applied to the battery and characterized by categorizing different stresses represented in the training data, and a learning parameter determiner configured to use at least one processing device to determine a learning parameter based on the characterized training stress pattern, the learning parameter being determined for use in estimating a life of the battery.
The training data may be derived from a previous measuring of physical properties of the battery.
The training stress pattern extractor may be configured to extract the training stress pattern from the training data using a rainflow counting scheme, and the training stress pattern may represent a plurality of cycles that respectively represent changes in values of the training data over time.
The training stress pattern extractor may be configured to perform the categorizing by extracting a level for each of the plurality of cycles from a plurality of levels of a determined parameter, and configured to generate characteristic data based on a determined number of cycles, of the plurality of cycles, that correspond to each of the plurality of levels, so that the characteristic data represents a characteristic of the training stress pattern.
The determined parameter may include at least one of an offset, an amplitude, and a period of each of the plurality of cycles.
The training stress pattern extractor may be configured to create a plurality of combination parameters, each representing respective levels for each of a plurality of the determined parameters for a cycle, and configured to perform the categorizing by generating the characteristic data based on a determined number of cycles, of the plurality of cycles, whose determined parameters correspond to each of the plurality of combination parameters.
The learning parameter determiner may be configured to extract the learning parameter by inputting the characteristic data to a predetermined learner.
The apparatus may include a communication interface, wherein the learning parameter determiner is configured to transmit the extracted learning parameter to an external apparatus using the communication interface.
The apparatus may include a storage, wherein the learning parameter determiner is configured to store the extracted learning parameter in the storage.
One or more embodiments provide a battery life estimation apparatus including a stress pattern extractor configured to use at least one processing device to generate characterization data that categorizes different stresses of a battery from acquired sensing data of the battery, and a life estimator configured to use at least one processing device to estimate and output a life of the battery based on the characterization data.
One or more embodiments provide a battery life estimation method including acquiring sensing data for physical properties of a battery, extracting, using at least one processing device, a stress pattern from the sensing data, the stress pattern representing changes in states of the battery based on stresses applied to the battery and characterized by categorizing different stresses represented in the sensing data, and estimating a life of the battery based on the categorized stress pattern.
One or more embodiments provide a battery life estimation method including acquiring training data for physical properties for a battery, extracting, using at least one processing device, a training stress pattern from the training data, the training stress pattern representing changes in states of the battery based on stresses applied to the battery and characterized by categorizing different stresses represented by the training data, and determining, using at least one processing device, a learning parameter based on the characterized training stress pattern, the learning parameter being determined for use in estimating a life of the battery.
One or more embodiments provide a non-transitory computer-readable storage medium including computer readable code to cause at least one processing device to perform one or more method embodiments set forth herein.
Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
Throughout the drawings and the detailed description, unless otherwise described or provided, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.
The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, after an understanding of the present disclosure, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent to one of ordinary skill in the art. The sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Also, descriptions of functions and constructions that may be well known to one of ordinary skill in the art may be omitted for increased clarity and conciseness.
The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein.
Various alterations and modifications may be made to the exemplary embodiments, some of which will be illustrated in detail in the drawings and detailed description. However, it should be understood that these embodiments are not construed as limited to the illustrated forms and include all changes, equivalents or alternatives within the idea and the technical scope of this disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “include” and/or “have,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, in view of the present disclosure. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout. When it is determined a detailed description of a related known function or configuration may make a purpose of an embodiment of the present disclosure unnecessarily ambiguous in describing the embodiment, the detailed description may be omitted herein.
The top graph of
As only an example, a single cycle associated with charging and discharging of the battery may indicate a cycle in which power of a fully charged battery is completely discharged and the battery is recharged. For example, a section between the points in time 111 and 112 may be such a single cycle. Here, a “full cycle” may be considered a cycle where the battery is charged, either fully charged or partially charged, from a fully discharged or partially discharged state and where the battery is then discharged, either fully discharged or partially discharged, from that resultant charged state. Similarly, the “full cycle” may be considered a cycle where the battery is discharged, either fully discharged or partially discharged, from a fully charged or partially charged state and where the battery is then charged, either fully charged or partially charged, from that resultant discharged state. Differently, herein, a “half cycle” may be considered a cycle (or portion of a cycle) where the battery is charged, either fully charged or partially charged, from a fully discharged or partially discharged state. Likewise, the “half cycle” may be considered a cycle (or portion of a cycle) where the battery is discharged, either fully discharged or partially discharged, from a fully charged or partially charged state.
The bottom graph of
Referring to
As illustrated in
Thus, in the present disclosure, according to one or more embodiments, a battery life may correspond to, for example, a current capacitance value of the battery, an internal resistance value of the battery, or such an SOH of a battery. The SOH may be defined by the below Equation 1, for example.
The C-rate may represent a unit of measure used to set a current value, under various use conditions, during charging and discharging of a battery, and may be used to predict or mark a period of time during which a battery is available. The C-rate may be denoted as C, and may be defined by the below Equation 2, for example.
The graph of
A voltage pattern or a current pattern may change depending on whether the battery is charging or discharging. For example, an influence of the same voltage value or the same current value on a life of the battery may be interpreted to be determined based on whether the battery is being charged or discharged.
In
The left graph of
Stress may be applied to the battery based on charging and discharging of the battery. The stress may represent damage to the battery based on the charging and discharging of the battery. Accordingly, as an amount of stress applied to the battery increases, the life of the battery may decrease.
In the left graph, a voltage of the battery increases during charging of the battery, and decreases during discharging of the battery. When the battery is charged and discharged once, a single voltage full cycle occurs as shown in the left graph. The voltage cycle thus corresponds to a stress pattern that reflects a damage state of the battery.
Various voltage cycles may occur based on a type of charging and/or discharging. In
Referring to
The battery life estimation apparatus 1000 may estimate a state of a battery (for example, an SOH), e.g., as an energy source in an EV embodiment of the present disclosure. For example, the battery life estimation apparatus 1000 may provide more exact state information of EVs to drivers of the EVs by more accurately estimating an SOH, and accordingly drivers may have a more positive opinion about EVs such as they do for gasoline powered vehicles. Additionally, depending on embodiment, the battery life estimation apparatus 1000 may be lighter in weight compared to previous estimation systems, and may even be mounted in a battery management system (BMS), such as a BMS in an EV embodiment of the present disclosure. Furthermore, depending on embodiment, the battery life estimation apparatus 1000 may be applicable to all physical applications employing batteries, in addition to EVs.
The sensing data acquirer 1010 may acquire sensing data of the battery. The sensing data may include, for example, at least one of voltage data, current data, and temperature data. In an embodiment, the sensing data acquirer 1010 may be a system that also includes such sensors. For example, the voltage data, the current data, and the temperature data may be respectively acquired from one or more voltage sensors, current sensors, and temperature sensors that may be configured to sense such physical characteristics or properties of the battery. Also, the sensing data may include data acquired from additional or alternative sensors, for example, a pressure sensor and a humidity sensor, in addition to any, or any combination, of the voltage sensor, the current sensor, and the temperature sensor. The sensing data acquirer 1010 may be a system that also includes such additional or alternative sensors. As only an example, the sensing data may refer to time-series data sensed during a predetermined time interval. For example, the voltage sensor may sense a voltage of the battery for “10” seconds (sec), e.g., based on a control signal or flag of the sensing data acquirer 1010, and the sensing data acquirer 1010 may acquire that sensed data for that predetermined time interval from the voltage sensor.
In such an example, the sensing data acquirer 1010 may routinely or periodically update such sensing data. For example, when an update period of “24” hours is set, the sensing data acquirer 1010 may acquire sensing data every “24” hours from a sensor that is configured to sense a characteristic of the battery. The update period may be set in advance, or set variably by an external apparatus, as only examples. The external apparatus refers to apparatuses other than the battery life estimation apparatus 1000.
In another example, the sensing data acquirer 1010 may acquire such sensing data based on a control signal received from the external apparatus. For example, in response to a control signal from the external apparatus instructing the battery life estimation apparatus 1000 to estimate the battery life, the sensing data acquirer 1010 may receive or obtain sensing data from a sensor configured to sense one or more characteristics of the battery.
The stress pattern extractor 1020 may extract a stress pattern from the obtained sensing data. As noted above, stress refers to the damage on the battery caused by charging and discharging of the battery, or another action that damages the battery. The stress pattern refers to a pattern in which a state of the battery changes based on stress applied to the battery.
The stress may be applied to the battery by charging and discharging of the battery and accordingly, a life of the battery may be reduced. When stress is applied to the battery, the state of the battery, for example a voltage, a current, or a temperature of the battery, may change. The stress pattern extractor 1020 may thus extract a stress pattern of the battery from the sensing data. For example, the voltage of the battery may increase when the battery is charged and may decrease when the battery is discharged. In this example, the voltage of the battery may change based on the level of the applied stress and thus, the stress pattern extractor 1020 may extract or interpret a voltage cycle based on charging and discharging of the battery as a stress pattern.
As only an example, the stress pattern extractor 1020 may extract the stress pattern from the sensing data using a rainflow counting scheme. The stress pattern may include a plurality of cycles representing changes in values of the differing sensing data. The plurality of extracted or interpreted cycles may be the “full cycle” or “half cycle” discussed above. Thus, the full cycle is a cycle of an increase and decrease in a value of the sensing data over time, and the half cycle is a cycle of either an increase or a decrease in a value of the sensing data over time.
In an example, the stress pattern extractor 1020 may apply the rainflow counting scheme to any of voltage data, current data, or pressure data of the battery, sensed or measured during a predetermined period of time, to extract an example stress pattern. In another example, the stress pattern extractor 1020 may apply the rainflow counting scheme to another sensing data representing the state of the battery other than the voltage data, the current data, and the pressure data, to extract an example stress pattern. In still another example, to extract a stress pattern from the sensing data, the stress pattern extractor 1020 may use other schemes of extracting the stress pattern, in addition or alternatively to the rainflow counting scheme.
Thus, the stress pattern extractor 1020 generates characteristic data representing a characteristic of the stress pattern(s). Herein, characteristic data may refer to categorized data obtained by quantifying a stress pattern. The characteristic data may be, for example, in the form of a histogram.
For example, the stress pattern extractor 1020 may extract a level corresponding to each of the plurality of cycles from a plurality of levels of respective predetermined parameters, and generate the characteristic data based on the extracted level. The predetermined parameter may include, for example, at least one of an offset, an amplitude, and a period of each of the plurality of cycles, such as illustrated in the right graph of
For example, the stress pattern extractor 1020 may divide or categorize an amplitude of a cycle into four level ranges or categories. When a stress pattern includes ten cycles, and the ten cycles have amplitudes of “1.5,” “1.7,” “2.1,” “2.5,” “3.2,” “3.6,” “3.8,” “4.3,” “4.5,” and “4.6,” respectively, the stress pattern extractor 1020 may calculate that two cycles correspond to a first range with an amplitude of “1” to “2,” that two cycles correspond to a second range with an amplitude of “2” to “3,” that three cycles correspond to a third range with an amplitude of “3” to “4,” and that three cycles correspond to a fourth range with an amplitude of “4” to “5.” Thus, the stress pattern extractor 1020 may generate bins respectively corresponding to the first through the fourth ranges, and may generate a histogram, such as a histogram in which each of bins corresponding to the first range and the second range has a size of “2” and each of bins corresponding to the third range and the fourth range has a size of “3.”
In an example, when a plurality of parameters are used for each extracted cycle, the stress pattern extractor 1020 may create a plurality of combination parameters by combining a plurality of levels of the plurality of parameters, may calculate a number of cycles corresponding to each of the plurality of combination parameters among the plurality of cycles, and may generate the characteristic data. A combination parameter may include or represent a respective level or range for each of the parameters represented by the combination parameter. There may also be such a combination parameter for each extracted cycle. In this example, the stress pattern extractor 1020 may calculate the number of cycles using a weight based on an extracted or interpreted cycle pattern of the plurality of cycles. For example, when an offset, an amplitude, and a period are determined in advance as parameters, and when the stress pattern extractor 1020 divides each of the offset, the amplitude, and the period into three level ranges or categories, the stress pattern extractor 1020 may combine one of three level ranges of the offset, one of three level ranges of the amplitude, and one of three level ranges of the period, to create 27 bins, i.e., 33 bins, that each represent one of three level ranges of the offset, one of three level ranges of the amplitude, and one of three level ranges of the period. The stress pattern extractor 1020 may calculate a number of cycles that correspond to or match each of the 27 bins. As only an example, the stress pattern extractor 1020 may also set a weight to an interpreted half cycle differently from a weight set an interpreted full cycle, and may calculate the number of cycles based on the set weights. For example, when the stress pattern extractor 1020 sets the weight of half cycles to “0.5” and sets the weight of full cycles to “1,” when a single half cycle and two full cycles correspond to a first bin, and when five half cycles and a single full cycle correspond to a second bin, the stress pattern extractor 1020 may set or determine the number of cycles that correspond to or match the first bin and the number of cycles that correspond to or match the second bin to be “2.5” and “3.5,” respectively. Accordingly, the stress pattern extractor 1020 may generate a histogram based on such a determined number of cycles corresponding to each bin.
In another example, the stress pattern extractor 1020 may generate the characteristic data based on a predetermined period, and may generate a single piece of characteristic data by accumulating extracted characteristic data over multiple predetermined periods. For example, when the stress pattern extractor 1020 extracts a stress pattern from sensing data acquired for “60,000” seconds, with an extraction period of “30,000” seconds, the stress pattern extractor 1020 may extract first characteristic data from sensing data acquired during a period of “0” seconds to “30,000” seconds and may extract second characteristic data from sensing data acquired during a period of “30,000” seconds to “60,000” seconds, and then accumulate the first characteristic data and the second characteristic data, and generate a single piece of characteristic data.
In an embodiment, the stress pattern extractor 1020 may represent the characteristic data as a vector.
The life estimator 1030 may estimate the life of the battery based on the extracted stress pattern. In an embodiment, the life estimator 1030 may input characteristic data representing a characteristic of the stress pattern to a predetermined learner, and may estimate the life of the battery. As only an example, the life estimator 1030 may input, to the predetermined learner, characteristic data extracted from voltage data, or three pieces of characteristic data extracted from each of voltage data, current data, and temperature data. With the learner, when an input and output, the learner may have been caused to learn a parameter to generate an output corresponding to the input, such as discussed below with regard to
Thus, to more accurately estimate the life of the battery, the life estimator 1030 may apply a predetermined learning parameter to a predetermined learner. In an example, when the predetermined learner is the NN model predetermined learner, the predetermined learning parameter may include activation functions, a weight, and a connection pattern between neurons. In another example, when the predetermined learner is the support vector regression model predetermined learner, the predetermined learning parameter may include a kernel function and a penalty parameter. In still another example, when the predetermined learner is the Gaussian process regression model predetermined learner, the predetermined learning parameter may include a kernel function and a hyperparameter.
In an embodiment, the life estimator 1030 may receive such a learning parameter from an external apparatus (for example, a preprocessing apparatus) using a communication interface, and input the received learning parameter to the predetermined learner. The external apparatus may include, for example, apparatuses other than the battery life estimation apparatus 1000. In the following description, the communication interface may include, as only an example, a wireless Internet interface and a local area communication interface. The wireless Internet interface may include, as only an example, a wireless local area network (WLAN) interface, a wireless fidelity (Wi-Fi) Direct interface, a Digital Living Network Alliance (DLNA) interface, a Wireless Broadband (WiBro) interface, a World Interoperability for Microwave Access (WiMAX) interface, a High Speed Downlink Packet Access (HSDPA) interface, and other interfaces known to one of ordinary skill in the art. The local area communication interface may include, as only an example, a Bluetooth interface, a radio frequency identification (RFID) interface, an Infrared Data Association (IrDA) interface, a Ultra Wideband (UWB) interface, a ZigBee interface, a near field communication (NFC) interface, and other interfaces known to one of ordinary skill in the art. In addition, the communication interface may include, for example, all interfaces (for example, a wired interface) communicable with the external apparatus. Depending on embodiment, the communication interface may also, or alternatively, be used for alternate communications and sharing of information operations.
In an example, the battery life estimation apparatus 1000 includes a storage configured to store in advance the predetermined learning parameter. In this example, the life estimator 1030 may extract the learning parameter from the storage and apply the extracted learning parameter to the predetermined learner. Also, the life estimator 1030 may learn, or have learned, a parameter based on various stress patterns and may extract the learning parameter, as discussed below with regard to
In another example, the battery life estimation apparatus 1000 may include a dimension transformer configured to reduce a dimension of the characteristic data. For example, the dimension transformer may reduce the dimension of the characteristic data using a principal component analysis (PCA) or a linear discriminant analysis (LDA), both of which may minimize the loss of information during the dimension reduction. The life estimator 1030 may input the characteristic data with the reduced dimension to the predetermined learner, which may estimate the life of the battery based on the reduced dimension characteristic data. By inputting the characteristic data with the reduced dimension to the predetermined learner, a time required for the life estimator 1030 to estimate the life of the battery may be reduced.
In an example, when characteristic data is input to a learner, the learner may output a remaining capacity of a battery. The life estimator 1030 may extract battery life information from the output remaining capacity. The battery life information may be calculated using the below Equation 3, for example.
In Equation 3, SoH denotes the battery life information, C1 denotes a capacity of the battery at a time of manufacturing of the battery, for example, and Ce denotes the output remaining capacity of the battery. For example, when the capacities C1 and Ce are set to 50 kilowatt hour (kWh) and 40 kWh, respectively, the life estimator 1030 may calculate a life of the battery to be 80%.
Referring to
The battery life estimation apparatus 1100 may determine a learning parameter in order to estimate a life of a battery. For example, the battery life estimation apparatus 1100 may perform a preprocessing process of the battery life estimation apparatus 1000 of
The training data acquirer 1110 may acquire training data of the battery. The training data may include, for example, any, or any combination, of voltage data, current data, and temperature data of a battery. Also, the training data may include additional data representing a state of such a battery (for example, pressure data and humidity data). The training data acquirer 1110 may acquire training data of a single battery or training data of a plurality of batteries or battery cells. Additionally, the training data acquirer 1110 may acquire training data from a predetermined database or an external apparatus. For example, the training data acquirer 1110 may update the training data from the predetermined database or the external apparatus based on an update period, or may acquire the training data from the predetermined database or the external apparatus based on a control signal received from the external apparatus.
The training stress pattern extractor 1120 may extract a training stress pattern from the training data. The training stress pattern refers to a pattern in which a state of a battery, from which training data is sensed, changes based on stress applied to the battery. In an example, the training stress pattern extractor 1120 may use a rainflow counting scheme to extract the training stress pattern from the training data. In this example, the training stress pattern may include a plurality of cycles representing changes in values of the training data over time. The plurality of cycles may be a full cycle or a half cycle. The training stress pattern extractor 1120 may use other extracting schemes to extract the training stress pattern from the training data, in addition or alternatively to the rainflow counting scheme.
The training stress pattern extractor 1120 may extract a level corresponding to each of a plurality of cycles among a plurality of levels of respective predetermined parameters, and generate characteristic data based on a number of cycles corresponding to each of the plurality of levels among the plurality of cycles. As noted above, characteristic data may refer to categorized data obtained by quantifying a stress pattern(s). The predetermined parameter may include, as only an example, any, or any combination, of an offset, an amplitude, and a period of each of the plurality of cycles. Similar to the stress pattern extractor 1020 of
For example, the training stress pattern extractor 1120 may divide a parameter into a plurality of level ranges or categories, and may generate a bin corresponding to each of the level ranges. The training stress pattern extractor 1120 may calculate a number of cycles that correspond to each of the plurality of levels, and may set or determine a size of a bin, for a predetermined level range, to be the number of cycles corresponding to the predetermined level range. The training stress pattern extractor 1120 may generate a histogram including bins as characteristic data.
When a plurality of parameters are used for an extracted or interpreted cycle, the training stress pattern extractor 1120 may create a plurality of combination parameters by combining a plurality of levels or ranges of the plurality of parameters, may calculate a number of cycles that correspond to each of the plurality of combination parameters among the plurality of cycles, and may generate the characteristic data. Each of the combination parameters may include or represent levels or ranges for each of plural parameters. The training stress pattern extractor 1120 may generate a plurality of bins corresponding to each of the plurality of combination parameters, may set or determine a size of a bin, for a predetermined combination parameter, to be the number of cycles that correspond to or match the predetermined combination parameter, and may generate a histogram based on the same. The training stress pattern extractor 1120 may represent the characteristic data as a vector. In an example, the training stress pattern extractor 1120 may also reduce a dimension of the characteristic data using a PCA or an LDA.
The learning parameter determiner 1130 may determine a learning parameter based on the training stress pattern. The learning parameter may then be used to estimate the life of the battery. The learning parameter determiner 1130 may extract the learning parameter by inputting characteristic data representing a characteristic of the training stress pattern to a predetermined learner. As noted, in an embodiment, characteristic data may be represented in the form of a vector. The predetermined learner may learn, based on the characteristic data, such a learning parameter optimized for a learning model of the predetermined learner. For example, the predetermined learner may use any, or any combination, of an NN model, a support vector regression model, and a Gaussian process regression model. In an example, when the predetermined learner is the NN model predetermined learner, the determined learning parameter may include activation functions, a weight, and a connection pattern between neurons. In another example, when the predetermined learner is a support vector regression model predetermined learner, the determined learning parameter may include a kernel function and a penalty parameter. In still another example, when the predetermined learner is a Gaussian process regression model predetermined learner, the determined learning parameter may include a kernel function and a hyperparameter. The predetermined learner may use another learning model capable of estimating the life of the battery based on the characteristic data, in addition to or instead of using the NN model, the support vector regression model, and/or the Gaussian process regression model. The learning parameter determined by the learning parameter determiner 1130 may be used when the battery life estimation apparatus 1100 estimates the life of the battery. For example, the life estimator 1030 of
In an example, the battery life estimation apparatus 1100 may include a storage, and the learning parameter determiner 1130 may store the determined learning parameter in the storage. Additionally, the learning parameter determiner 1130 may transmit the determined learning parameter to an external apparatus using a communication interface. As another example, the battery life estimation apparatus 1000 of
Referring to
In an embodiment, the battery 1210 supplies power to a driving vehicle embodiment of the present disclosure that includes the battery 1210. The battery 1210 may include a plurality of battery modules. Capacities of the plurality of battery modules may be the same as or different from each other.
The sensor 1220 may acquire sensing data of the battery 1210. In the illustrated battery system of
The battery control apparatus 1230 may include a real-time clock (RTC) 1240, a buffer 1250, a battery life estimation apparatus 1260, and a communication interface 1270, for example.
The buffer 1250 may store the sensing data of the battery 1210 obtained or received from the sensor 1220.
The RTC 1240 may keep a current time, for example. The battery life estimation apparatus 1260 may record, using the RTC 1240, a point in time at which the sensing data is received from the sensor 1220.
The battery life estimation apparatus 1260 may include a cycle extractor 1261, a pattern accumulator 1262, a life estimator 1263, and a memory 1264, for example.
The cycle extractor 1261 may extract a plurality of cycles representing a stress pattern from the sensing data stored in the buffer 1250, e.g., using a rainflow counting scheme. The plurality of cycles represent changes in values of the sensing data over time.
The pattern accumulator 1262 may generate characteristic data by quantifying the plurality of cycles. For example, the generated characteristic data may be represented in the form of a histogram. The pattern accumulator 1262 may extract a level corresponding to each of the plurality of cycles from among a plurality of levels of a predetermined parameter, and generate the characteristic data based on the extracted level. The predetermined parameter may be, as only examples, any, or any combination, of an offset, an amplitude, and a period of each of the plurality of cycles. The pattern accumulator 1262 may calculate a number of cycles corresponding to each of the plurality of levels among the plurality of cycles, and generate the characteristic data based on the number of cycles. The pattern accumulator 1262 may calculate the number of cycles using differing weights based on different extracted or interpreted cycle patterns of the plurality of cycles. Additionally, the pattern accumulator 1262 may divide the predetermined parameter into a plurality of level ranges or categories, and may generate a bin corresponding to each of the level ranges. The pattern accumulator 1262 may set or determine a size of a bin, for a predetermined level range, to be the number of cycles that correspond to or match the predetermined level range, and may generate a histogram including bins as characteristic data.
When a plurality of parameters are used for each extracted or interpreted cycle, the pattern accumulator 1262 may create a plurality of combination parameters by combining a plurality of levels or ranges of the plurality of parameters, may calculate the number of cycles whose parameters correspond to or match each of the plurality of combination parameters among the plurality of cycles, and may generate the characteristic data. A combination parameter may represent plural levels or ranges for each of the parameter of the combination parameter.
The pattern accumulator 1262 may generate a plurality of bins respectively corresponding to each of the plurality of combination parameters, may set or determine a size of a bin for a predetermined combination parameter to be the number of cycles whose parameters correspond to or match the predetermined combination parameter, and may generate a histogram. For example, the pattern accumulator 1262 may represent the characteristic data as a vector. In an example, the pattern accumulator 1262 may reduce a dimension of the characteristic data using a PCA or an LDA. In another example, the pattern accumulator 1262 may generate characteristic data based on multiple predetermined periods, may accumulate extracted characteristic data over the multiple predetermined periods, and may generate a single piece of characteristic data from the accumulated extracted characteristic data.
The life estimator 1263 estimates the life of the battery based on the corresponding stress pattern represented by the characteristic data. Thus, the life estimator 1263 may input characteristic data representing a characteristic of the stress pattern to a predetermined learner, and may estimate the life of the battery. For example, with the predetermined learner, when an input and output are given, the learner may be, or have been, caused to learn a learning parameter to generate an output corresponding to the input. The learner may use, for example, one of an NN model, a support vector regression model, and a Gaussian process regression model.
Additionally, the life estimator 1263 may apply a predetermined learning parameter stored in the memory 1264 to the predetermined learner. For example, when the NN model is implemented by the predetermined learner, the life estimator 1263 may extract an activation function stored in the memory 1264, and may apply the activation function to the predetermined learner.
The life estimator 1263 may transmit information on the estimated life of the battery to an external apparatus (for example, an electronic control unit (ECU) of a vehicle embodiment) via the communication interface 1270.
Referring to
A battery life estimation apparatus extracts or interprets a plurality of cycles from sensing data, e.g., using a rainflow counting scheme. In the left graph, the battery life estimation apparatus extracts or interprets cycles from voltage data 1301, which may include half cycles 1311 through 1317 and full cycles 1321 through 1326. As explained above, a full cycle refers to charging and discharging or a discharging and a charging sequence of the battery, while differently a half cycle may be a charging or discharging sequence. For example, full cycle 1321 includes a charging and discharging of the battery and full cycle 1323 includes a discharging and charging of the battery, while half cycle 1311 may include only a charging of the battery and half cycle 1312 may include only a discharging of the battery.
The right graph of
In the right graph, the battery life estimation apparatus may determine or set a period 1351, an amplitude 1352, and an offset 1353 (for example, a median value) as parameters of the full cycle 1326. Thus, the battery life estimation apparatus may extract the period 1351, the amplitude 1352, and the offset 1353, combine a level of each of the period 1351, the amplitude 1352, and the offset 1353, and generate characteristic data of the full cycle 1326.
The battery life estimation apparatus calculates a number of cycles whose parameters correspond to or match each of 64 bins, i.e., 43 bins. The battery life estimation apparatus calculates the number of cycles by setting a weight for the full cycle 1411 to be different from a weight set for the half cycle 1412. For example, when the weight of the full cycle 1411 and the weight of the half cycle 1412 are set to “1” and “0.5,” respectively, the battery life estimation apparatus may calculate a number of the full cycles 1411 as “1,” and calculate a number of half cycles 1412 as “0.5.”
The graph 1501 of
A battery life estimation apparatus may generate characteristic data based on voltage data, e.g., every predetermined period. For example, in
Referring to
The battery control apparatus may transmit the estimated life of the battery to the ECU, for example, and the ECU may control the user interface 1610 to display the life of the battery received from the battery control apparatus.
Referring to
In addition to the above example of
Referring to
In operation 1820, a stress pattern may be extracted from the sensing data. The stress pattern refers to a pattern in which states of the battery change based on stresses applied to the battery.
In operation 1830, a life of the battery may be estimated based on the extracted stress pattern.
As noted, the above disclosures regarding
Referring to
In operation 1920, a training stress pattern may be extracted from the training data. The training stress pattern refers to a pattern in which states of a battery, from which training data is sensed or determined, change based on stresses applied to the battery.
In operation 1930, a learning parameter may be determined based on the training stress pattern. The learning parameter is used to estimate a life of the battery.
In addition, as explained above, operations 1910 through 1930 may be performed in combination operations 1810 through 1830 of
As noted, the above disclosures regarding
The apparatuses, units, modules, devices, and other components illustrated in
The methods illustrated in
Instructions or software to control a processing device, processor, or computer to implement the hardware components and perform the methods as described above may be written as computer programs, code segments, instructions or any combination thereof, for individually or collectively instructing or configuring the processing device, processor, or computer to operate as a machine or special-purpose computer to perform the operations performed by the hardware components and the methods as described above. In one example, the instructions or software include machine code that is directly executed by the processing device, processor, or computer, such as machine code produced by a compiler. In another example, the instructions or software include higher-level code that is executed by the processing device, processor, or computer using an interpreter. Based on the disclosure herein, and after an understanding of the same, programmers of ordinary skill in the art can readily write the instructions or software based on the block diagrams and the flow charts illustrated in the drawings and the corresponding descriptions in the specification, which disclose algorithms for performing the operations performed by the hardware components and the methods as described above.
The instructions or software to control a processing device, processor, or computer to implement the hardware components, such as discussed in any of
As a non-exhaustive example only, an electronic device embodiment herein, e.g., that includes an apparatus estimating a state of a battery, as described herein, may be a vehicle, a mobile device, such as a cellular phone, a smart phone, a wearable smart device, a portable personal computer (PC) (such as a laptop, a notebook, a subnotebook, a netbook, or an ultra-mobile PC (UMPC), a tablet PC (tablet), a phablet, a personal digital assistant (PDA), a digital camera, a portable game console, an MP3 player, a portable/personal multimedia player (PMP), a handheld e-book, a global positioning system (GPS) navigation device, or a sensor, or a stationary device, such as a desktop PC, a high-definition television (HDTV), a DVD player, a Blu-ray player, a set-top box, or a home appliance, or any other mobile or stationary device capable of wireless or network communication.
While this disclosure includes specific examples, it will be apparent to one of ordinary skill in the art that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is not limited by the detailed description, but further supported by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.
Number | Date | Country | Kind |
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10-2015-0010058 | Jan 2015 | KR | national |