CN117031281A - Method, system, equipment, medium and battery system for detecting battery health state - Google Patents
Method, system, equipment, medium and battery system for detecting battery health state Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The present disclosure provides a method, a system, a device, a medium and a battery system for detecting a battery health state, wherein the detection method includes obtaining an actual impedance value corresponding to sine wave excitation of a battery to be detected at a target frequency; acquiring a theoretical impedance range value corresponding to the battery to be tested under the excitation of the sine wave of the target frequency; and detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value. According to the method and the device, the impedance corresponding to the whole frequency domain covering the low frequency band to the high frequency band is not required to be detected, the target frequency capable of reflecting the electrochemical polarization process and the concentration polarization process is selected by locating in the frequency domain, the impedance value of the battery under the target frequency is obtained, and then the health state of the battery in the electrochemical polarization process and the concentration polarization process is detected, so that time and labor are saved, and the health state of the battery can be detected quickly and simply.
Description
Technical Field
The disclosure relates to the technical field of batteries, and in particular relates to a method, a system, equipment, a medium and a battery system for detecting a battery health state.
Background
Battery state of health detection is of great importance in battery applications that are increasingly popular today. With the rapid development of electric vehicles, wearable devices, mobile devices, renewable energy systems, and the like, the reliability and performance of batteries are critical to the user's experience and stable operation of the devices. However, the battery is affected by factors such as capacity fade, increase in internal resistance, self-discharge, and temperature effect during long-term use, resulting in a decrease in its state of health.
The polarization process of the battery comprises electrochemical polarization and concentration polarization, and the battery health state information can be effectively reflected through the extraction of relevant parameters in the battery polarization process. The rapid battery polarization can lead to more severe temperature rise of the battery, heat can be generated by chemical reaction and current flow in the polarization process, and the rapid polarization process can accelerate heat accumulation and distribution, so that the temperature of the battery is raised more rapidly. However, too slow polarization of the battery reflects that electrochemical reaction is blocked and lithium ion diffusion resistance is too large in the battery, so that the charge and discharge efficiency of the battery is affected. In the electrochemical polarization process, the electrochemical reaction process is not fast enough, and in the concentration polarization process, the electrochemical polarization process and the concentration polarization process should be distributed in a normal range, and the impedance of the cell in the electrochemical polarization process and the concentration polarization process can reflect the health state of the cell.
In the prior art, a battery electrochemical impedance spectrum EIS (Electrochemical impedance spectroscopy) is adopted to study the health state of a battery, and whether the battery is healthy or not is diagnosed from the change of battery electrochemical impedance spectrum parameters by detecting the impedance in each frequency in the whole frequency domain covering low frequency to high frequency; or the battery is placed for a long time, the impedance of the battery is obtained in a time domain range, and the health state of the battery is judged, and the two methods are very time-consuming and have large workload.
Disclosure of Invention
The technical problem to be solved by the present disclosure is to provide a method, a system, a device, a medium and a battery system for detecting the health status of a battery, in order to overcome the defect that the health status of the battery cannot be detected rapidly and simply in the prior art.
The technical problems are solved by the following technical scheme:
in a first aspect, a method for detecting a state of health of a battery is provided, the method comprising:
acquiring an actual impedance value corresponding to sine wave excitation of a battery to be tested at a target frequency;
acquiring a theoretical impedance range value corresponding to the battery to be tested under the excitation of the sine wave of the target frequency;
detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value;
the target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency;
the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
Preferably, the first target frequency is at least one of intermediate frequency bands;
the second target frequency is at least one of the low frequency bands.
Preferably, the step of obtaining the theoretical impedance range value corresponding to the to-be-measured battery under the excitation of the sine wave of the target frequency includes:
inputting sine wave excitation of the target frequency to a plurality of sample test batteries in a healthy state, and obtaining a corresponding sample impedance value of the sample test batteries under the sine wave excitation of the target frequency;
the theoretical impedance range value is derived based on a number of the sample impedance values.
Preferably, the step of detecting the state of health of the battery to be detected based on the actual impedance value and the theoretical impedance range value includes:
training based on the theoretical impedance range value to obtain a preset battery state detection model;
and inputting the actual impedance value into the preset battery state detection model, and outputting the health state of the battery to be detected.
Preferably, the step of detecting the state of health of the battery to be detected based on the actual impedance value and the theoretical impedance range value includes:
judging whether the actual impedance value accords with the theoretical impedance range value or not;
if yes, determining that the health state of the battery to be tested is healthy;
if not, determining that the health state of the battery to be tested is unhealthy.
Preferably, the step of obtaining the actual impedance value corresponding to the sine wave excitation of the battery to be measured at the target frequency includes:
generating a sine wave excitation of the target frequency with a PWM (Pulse Width Modulation, pulse width modulated) wave as a carrier wave;
inputting the sine wave excitation to the battery to be tested, and obtaining the actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency;
and/or under different test parameters, acquiring the actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency.
Preferably, the step of obtaining the actual impedance value corresponding to the sine wave excitation of the battery to be measured at the target frequency includes:
acquiring a first impedance real part value and a first impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the first target frequency;
acquiring a second impedance real part value and a second impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the second target frequency;
calculating the first actual impedance value based on the first impedance real value and the first impedance imaginary value;
and calculating the second actual impedance value based on the second impedance real value and the second impedance imaginary value.
In a second aspect, there is also provided a detection system of a state of health of a battery, the detection system comprising:
the actual impedance acquisition module is used for acquiring an actual impedance value corresponding to sine wave excitation of the battery to be tested at the target frequency;
the theoretical impedance acquisition module is used for acquiring a theoretical impedance range value corresponding to the battery to be detected under the excitation of the sine wave of the target frequency;
the detection module is used for detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value;
the target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency;
the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
Preferably, the first target frequency is at least one of intermediate frequency bands;
the second target frequency is at least one of the low frequency bands.
Preferably, the theoretical impedance obtaining module is further configured to input sine wave excitation of the target frequency to a plurality of sample test batteries in a healthy state, and obtain a sample impedance value corresponding to the sample test batteries under the sine wave excitation of the target frequency; the theoretical impedance range value is derived based on a number of the sample impedance values.
Preferably, the detection module includes:
the model training unit is used for training to obtain a preset battery state detection model based on the theoretical impedance range value;
and the health detection unit is used for inputting the actual impedance value into the preset battery state detection model and outputting the health state of the battery to be detected.
Preferably, the detection module is further configured to determine whether the actual impedance value meets the theoretical impedance range value; if yes, determining that the health state of the battery to be tested is healthy; if not, determining that the health state of the battery to be tested is unhealthy.
Preferably, the actual impedance obtaining module includes:
an excitation generation unit configured to generate a sine wave excitation of the target frequency with a PWM wave as a carrier wave;
the impedance acquisition unit is used for inputting the sine wave excitation to the battery to be detected and acquiring the actual impedance value corresponding to the sine wave excitation of the battery to be detected at the target frequency;
and/or the actual impedance obtaining module is further configured to obtain, under different test parameters, the actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency.
Preferably, the actual impedance obtaining module is further configured to obtain a first impedance real part value and a first impedance imaginary part value corresponding to the to-be-measured battery under the excitation of the sine wave of the first target frequency; acquiring a second impedance real part value and a second impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the second target frequency; calculating the first actual impedance value based on the first impedance real value and the first impedance imaginary value; and calculating the second actual impedance value based on the second impedance real value and the second impedance imaginary value.
In a third aspect, a battery system is provided, including the above-mentioned battery state of health detection system.
In a fourth aspect, there is also provided an electronic device including a memory, a processor, and a computer program stored on the memory and configured to run on the processor, where the processor implements the method for detecting a state of health of a battery described above when the computer program is executed.
In a fifth aspect, there is also provided a computer storage medium having stored thereon a computer program which, when executed by a processor, implements the above-described method of detecting a state of health of a battery.
On the basis of conforming to the common knowledge in the art, the preferred conditions can be arbitrarily combined to obtain the preferred examples of the disclosure.
The positive progress effect of the present disclosure is:
according to the method, the system, the equipment, the medium and the battery system for detecting the battery health state, the impedance corresponding to the whole frequency domain covering the low frequency band to the high frequency band is not required to be detected, only the target frequency capable of reflecting the electrochemical polarization process and the concentration polarization process is needed to be selected by locating points in the frequency domain, the impedance value of the battery under the target frequency is obtained, and then the health state of the battery in the electrochemical polarization process and the concentration polarization process is detected, so that time and labor are saved, and the health state of the battery can be detected quickly and simply.
Drawings
Fig. 1 is a first flow chart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 2 is a second flow chart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 3 is a third flow chart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 4 is a first schematic diagram of a battery state of health in the method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 5 is a fourth flowchart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 6 is a second schematic diagram of a battery state of health in the method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 7 is a fifth flowchart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 8 is a sixth flowchart of a method for detecting a battery state of health according to embodiment 1 of the present disclosure;
fig. 9 is a schematic structural diagram of a battery state of health detection system according to embodiment 2 of the present disclosure;
fig. 10 is a schematic structural diagram of an electronic device provided in embodiment 4 of the present disclosure.
Detailed Description
The present disclosure is further illustrated by way of examples below, but is not thereby limited to the scope of the examples described.
Electrochemical polarization and concentration polarization are briefly described below:
with respect to electrochemical polarization
The Butler-Volmer equation (electrode process kinetic equation) is an equation describing the rate of electrode surface charge transfer reactions in electrochemistry and is used to study the kinetics of electrochemical reactions. Butler-Volmer equation oxidation and reduction reaction activation energy, butler-Volmer equation:
i＝A*i0*[exp((α1*F*η)/(RT))-exp((-α2*(1-α1)*F*η)/(RT))]；
where i is the current, A is the effective surface area of the electrode, i0 is the exchange current density, α is the transfer coefficient, F is the Faraday constant, η is the electrode overpotential, R is the gas constant, and T is the temperature.
Thus, the hyperbolic sine function is expressed according to the Euler formula as follows:
sinh(x)＝(e^x-e^(-x))/2；
hyperbolic sine functions are commonly used in physics to describe the phenomenon of continuous changes in string vibration, electromagnetic field distribution, etc., and are also widely used in engineering, signal processing, mathematical analysis, etc.
The result of the anti-hyperbolic sine function is a real number, which can be used to solve the phase angle in an ac circuit or to resolve the real part of the complex number.
Regarding concentration polarization
Weber resistance (Warburg impedance) is a resistance that describes the diffusion of ions, and is commonly used in electrochemical systems to represent the diffusion of ions in an electrolyte. The mathematical expression of weber impedance can be derived from the friedel and ohm's law.
The weber impedance is characterized by a linear increase with increasing frequency and a proportional relationship with root frequency. This is because the movement of ions is affected by resistance during ion diffusion, which is proportional to root frequency.
The mid-band of the sine wave can reflect electrochemical polarization, and the low-band can reflect concentration polarization process.
Example 1
The embodiment provides a method for detecting a battery state of health, as shown in fig. 1, the method includes:
s101, acquiring an actual impedance value corresponding to sine wave excitation of the battery to be tested at the target frequency.
S102, acquiring a theoretical impedance range value corresponding to the to-be-detected battery under the excitation of the sine wave of the target frequency.
And S103, detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value.
The target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency; the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
When a battery passes current, the potential deviates from the balance potential, which is called battery polarization, electrochemical reaction occurs on the surface of the electrode, the electrochemical reaction generally comprises electrochemical polarization and concentration polarization, the electrochemical polarization is caused by the phenomenon that the electrode potential deviates from the balance potential due to the fact that the electrochemical reaction process (electron gain and loss) is not fast enough, the electrochemical reaction of the concentration polarization is fast enough, the reaction consumption is larger than mass transfer, the concentration of reactants on the surface of the electrode is low, and the electrode potential deviates from the balance potential due to obvious difference with a body, therefore, the electrochemical polarization and the concentration polarization are distributed in a normal range, namely, the corresponding actual impedance value is in accordance with the theoretical impedance range value.
According to the method for detecting the battery health state, the impedance corresponding to the whole frequency domain covering the low frequency band to the high frequency band is not required to be detected, the target frequency capable of reflecting the electrochemical polarization process and the concentration polarization process is selected by locating points in the frequency domain, the actual impedance value of the battery under the target frequency is obtained, the actual impedance value is compared with the theoretical impedance range value, the battery health state in the electrochemical polarization process and the concentration polarization process can be detected, time and labor are saved, and the battery health state can be detected quickly and simply.
In an alternative embodiment, the first target frequency is at least one of the mid-frequency bands; the second target frequency is at least one of the low frequency bands.
Wherein, the middle frequency range is 10Hz (hertz) -1000Hz, the low frequency range is lower than 10Hz, the middle frequency range can reflect the electrochemical polarization process, and the low frequency range can reflect the concentration polarization process.
One frequency can be selected as a first target frequency in the intermediate frequency band, and a plurality of frequencies can be selected as the first target frequency in the intermediate frequency band; similarly, one frequency may be selected as the second target frequency in the low frequency band, or a plurality of frequencies may be selected as the second target frequency in the low frequency band to reflect the electrochemical polarization process and the concentration polarization process, respectively.
For example, measuring the impedance of the battery at a frequency point of 5Hz at a low frequency band to reflect the lithium ion diffusion characteristic, namely, the reaction concentration polarization process, so as to reflect the health state of the battery; and measuring the impedance of the battery at a 200Hz frequency point at a medium frequency to reflect the electrochemical charge transfer characteristic, namely the electrochemical polarization process, so as to reflect the health state of the battery.
According to the battery state of health detection method, the impedance corresponding to the whole frequency domain covering the low frequency band to the high frequency band is not required to be detected, only one first target frequency and one second target frequency are required to be selected from the middle frequency band and the low frequency band respectively, the electrochemical polarization process and the concentration polarization process are reflected, the actual impedance value of the battery under the target frequency is obtained, the actual impedance value is compared with the theoretical impedance range value, the state of health of the battery in the electrochemical polarization process and the concentration polarization process can be detected, time and labor are saved, and the state of health of the battery can be detected quickly and simply.
In an alternative embodiment, as shown in fig. 2, step S102 includes:
s1021, inputting sine wave excitation of a target frequency to a plurality of sample test batteries in a healthy state, and obtaining a corresponding sample impedance value of the sample test batteries under the sine wave excitation of the target frequency.
S1022, a theoretical impedance range value is obtained based on a plurality of sample impedance values.
The manufacturing parameters of the battery to be tested and the sample test battery are the same, and the manufacturing parameters include, but are not limited to, battery specification, production lot and manufacturer, that is, the battery to be tested and the sample test battery may be the same battery specification, the same production lot, the same manufacturer, etc., as long as the sample impedance value corresponding to the sample test battery is ensured to be capable of representing the health state of the battery to be tested.
The theoretical impedance range value is obtained through a plurality of sample impedance values. For example, data sorting, data cleaning, data screening, etc. may be performed on several sample impedance values to obtain theoretical impedance range values.
The battery to be tested can also be a sample test battery, for example, the corresponding historical data of the battery to be tested in the historical test process can be obtained, so that a theoretical impedance range value capable of representing the health state of the battery to be tested is obtained.
According to the battery state of health detection method, a large number of sample test batteries are tested to obtain theoretical impedance range values, the accuracy of the theoretical impedance range values is guaranteed, the accuracy of battery state of health detection is further guaranteed, the battery state of health in the electrochemical polarization process and the concentration polarization process can be detected, time and labor are saved, and the battery state of health can be detected quickly and simply.
In an alternative embodiment, as shown in fig. 3, step S103 includes:
s1031, training based on the theoretical impedance range value to obtain a preset battery state detection model.
S1032, inputting the actual impedance value into a preset battery state detection model, and outputting the state of health of the battery to be detected.
The training may be performed on a tree (iTree) model to obtain a preset battery state detection model, so as to determine whether an abnormality occurs in the battery state. The itrate is a random binary tree, with each node either forking or leaf nodes. Given a stack of data sets D, where all attributes of D are variables that are continuous, the construction of iTree is as follows:
randomly selecting an attribute Attr;
randomly selecting a Value of the attribute;
classifying each record according to Attr, placing records with Attr smaller than Value in a left subtree, and placing records with Value larger than or equal to Value in a right subtree;
recursively constructing the left and right subtrees until the following condition is satisfied:
the incoming dataset has only one record or a plurality of identical records;
the depth of the tree reaches a defined depth.
After the construction of the itrate is completed, it is only necessary to track on which leaf node of the itrate the test data falls to evaluate whether the data is abnormal data, and the abnormal data is usually distributed to the leaf nodes quickly, so that the path length (i.e. the number of edges) from the leaf node to the root node can be used to determine whether a record is abnormal.
The impedance is a real number, specifically, the impedance is composed of an imaginary impedance and a real impedance, in fig. 4, an abscissa X represents the real impedance (in milliohm) of an actual impedance value, and an ordinate Y represents the imaginary impedance (in milliohm) of the actual impedance value, wherein the actual impedance value of the battery to be measured corresponding to the data point A1 is abnormal data, that is, the state of health of the battery to be measured is unhealthy, and the actual impedance values of the battery to be measured corresponding to other data points except the data point A1 are normal data, that is, the state of health of the battery to be measured is healthy.
Other models may also be trained based on theoretical impedance range values to obtain a preset battery state detection model.
In an alternative embodiment, as shown in fig. 5, step S103 includes:
s1033, judging whether the actual impedance value accords with the theoretical impedance range value.
If yes, step S1034 is executed, and if no, step S1035 is executed.
S1034, determining that the health state of the battery to be tested is healthy.
S1035, determining that the health state of the battery to be tested is unhealthy.
The theoretical impedance range value can be obtained through a statistical method, and whether the actual impedance value accords with the theoretical impedance range value is judged.
As shown in fig. 6, theoretical impedance range values can be obtained by a 3 sigma (standard deviation) rule in a statistical method; the impedance is real, in particular composed of an imaginary impedance and a real impedance,
in fig. 6, if the data point A2 exceeds the 3σ range, that is, exceeds the theoretical impedance range value, the actual impedance value of the battery to be measured corresponding to the data point A2 is considered as abnormal data, that is, the state of health of the battery to be measured is unhealthy. The other data points except the data point A2 are in the 3 sigma range, and the corresponding actual impedance value of the battery to be measured is normal data, namely the health state of the battery to be measured is healthy.
In an alternative embodiment, as shown in fig. 7, step S101 includes:
s1011, sinusoidal excitation of the target frequency is generated using the PWM wave as the carrier wave.
S1012, inputting sine wave excitation to the battery to be tested, and obtaining an actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency.
Parameters related to PWM wave:
PWM frequency (pwm_frequency): the frequency of the PWM signal is specified in Hz.
PWM resolution (pwm_resolution): the resolution of the PWM signal, i.e., the number of bits of the PWM signal, is specified.
Parameters related to sine wave:
amplitude (amplitude): the amplitude of the sine wave is specified, depending on the resolution of the PWM signal. For a PWM signal of n-bit resolution, the amplitude is 2 n-1.
Base_frequency): determined by the resolution of the PWM signal. The base frequency refers to the period of each PWM signal, which can be calculated by dividing the PWM frequency by 2 n.
For each PWM period, the sampled value of the sinusoidal waveform is calculated from the nature of the sinusoidal function, which can be calculated using the following formula:
sample＝amplitude*sin(2*pi*frequency*t)；
where sample is the sample value, amplitude is the amplitude, frequency is the frequency of the sine wave, t is the current time, and pi is the circumference ratio.
To generate sinusoidal waveforms of different frequencies, this can be achieved by adjusting the frequency parameters in the sinusoidal function, and the frequency can be updated as needed in each PWM period to obtain the desired target frequency of the sinusoidal excitation for testing.
Specifically, a PWM wave may be generated by a PWM signal generator, and modulated to a sine wave excitation of a target frequency by a microcontroller.
In an alternative embodiment, step S101 includes:
s1013, acquiring an actual impedance value corresponding to sine wave excitation of the battery to be tested at the target frequency under different test parameters.
Among them, the test parameters include, but are not limited to, temperature, voltage, and SOC (battery remaining capacity).
The sine wave excitation is the excitation of small current, and in the test process, the corresponding battery temperature, battery voltage, battery residual capacity and the like under the excitation of the small current can be recorded, so that a reference table is formed, and the subsequent table lookup comparison is convenient.
In an alternative embodiment, as shown in fig. 8, step S101 includes:
s1014, acquiring a first impedance real part value and a first impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the first target frequency.
S1015, obtaining a corresponding second impedance real part value and a corresponding second impedance imaginary part value of the battery to be tested under the excitation of the sine wave of the second target frequency.
S1016, calculating to obtain a first actual impedance value based on the first impedance real value and the first impedance imaginary value.
S1017, calculating a second actual impedance value based on the second impedance real value and the second impedance imaginary value.
The real impedance value corresponding to the battery is a real number, and specifically comprises an imaginary impedance value and a real impedance value, and the first real impedance value is calculated by recording a first impedance real value and a first impedance imaginary value corresponding to the battery to be measured under the excitation of the sine wave of the first target frequency. The second actual impedance value is obtained by recording the corresponding second impedance real part value and second impedance imaginary part value of the battery to be measured under the sine wave excitation of the second target frequency, and how to record and calculate the actual impedance value according to the imaginary part impedance value and the real part impedance value is the prior art, and will not be described herein.
Example 2
The present embodiment provides a detection system for a battery state of health, as shown in fig. 9, the detection system includes:
the actual impedance acquisition module 1 is used for acquiring an actual impedance value corresponding to sine wave excitation of the battery to be tested at the target frequency;
the theoretical impedance acquisition module 2 is used for acquiring a theoretical impedance range value corresponding to the to-be-detected battery under the excitation of the sine wave of the target frequency;
the detection module 3 is used for detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value;
the target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency;
the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
In an alternative embodiment, the first target frequency is at least one of the mid-frequency bands; the second target frequency is at least one of the low frequency bands.
In an optional embodiment, the theoretical impedance obtaining module 2 is further configured to input sine wave excitation of a target frequency to a plurality of sample test batteries in a healthy state, and obtain a sample impedance value corresponding to the sample test batteries under the sine wave excitation of the target frequency; theoretical impedance range values are based on several sample impedance values.
In an alternative embodiment, the detection module 3 comprises:
a model training unit 31 for training to obtain a preset battery state detection model based on the theoretical impedance range value;
the health detection unit 32 is configured to input the actual impedance value to a preset battery state detection model, and output the health state of the battery to be tested.
In an alternative embodiment, the detection module 3 is further configured to determine whether the actual impedance value meets the theoretical impedance range value; if so, determining that the health state of the battery to be detected is healthy; if not, determining that the health state of the battery to be tested is unhealthy.
In an alternative embodiment, the actual impedance acquisition 1 module includes:
an excitation generating unit 11 for generating a sine wave excitation of a target frequency with the PWM wave as a carrier wave;
an impedance obtaining unit 12, configured to input sine wave excitation to the battery to be tested, and obtain an actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency;
in an optional embodiment, the actual impedance obtaining module 1 is further configured to obtain, under different test parameters, an actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency.
In an optional embodiment, the actual impedance obtaining module 1 is further configured to obtain a first impedance real value and a first impedance imaginary value corresponding to the to-be-measured battery under the excitation of the sine wave of the first target frequency; acquiring a second impedance real part value and a second impedance imaginary part value corresponding to the battery to be tested under sine wave excitation of a second target frequency; calculating a first actual impedance value based on the first impedance real part value and the first impedance imaginary part value; and calculating a second actual impedance value based on the second impedance real value and the second impedance imaginary value.
The working principle of the battery state of health detection system of the present embodiment is the same as that of the battery state of health detection method of embodiment 1, and will not be described here again.
According to the battery state of health detection system, the impedance corresponding to the whole frequency domain covering the low frequency band to the high frequency band is not required to be detected, the target frequency capable of reflecting the electrochemical polarization process and the concentration polarization process is selected by locating points in the frequency domain, the actual impedance value of the battery under the target frequency is obtained, the actual impedance value is compared with the theoretical impedance range value, the state of health of the battery in the electrochemical polarization process and the concentration polarization process can be detected, time and labor are saved, and the state of health of the battery can be detected quickly and simply.
Example 3
The present embodiment provides a battery system including the detection system of the battery state of health in embodiment 2.
Battery systems (BMS) are commonly called battery caregivers or battery households, and mainly aim to intelligently manage and maintain each battery unit, prevent overcharge and overdischarge of the battery, prolong the service life of the battery, monitor the state of the battery, and the like. The battery system unit may include a control module, a display module, a wireless communication module, an electric device, a battery pack for supplying power to the electric device, an acquisition module for acquiring battery information of the battery pack, a battery health state detection system in embodiment 2, and the like.
The battery system of this embodiment, based on the detection system of the battery state of health in embodiment 2, detects the state of health of the battery, need not to detect the impedance that covers the whole frequency domain that goes from the low frequency band to the high frequency band and corresponds, only need to select the target frequency that can reflect electrochemical polarization process and concentration polarization process in the frequency domain internal locating point, obtain the actual impedance value of battery under the target frequency, compare with theoretical impedance range value, can realize detecting the state of health of the battery in electrochemical polarization process and the concentration polarization process, labour saving and time saving can be fast, simple and convenient detects the state of health of the battery.
Example 4
Fig. 10 is a schematic structural diagram of the electronic device provided in this embodiment, where the electronic device includes a memory, a processor, and a computer program stored on the memory and capable of running on the processor, and the processor implements the method for detecting the battery state of health in embodiment 1 when executing the computer program. The electronic device 70 shown in fig. 10 is merely an example and should not be construed to limit the functionality and scope of use of embodiments of the present disclosure in any way. As shown in fig. 10, the electronic device 70 may be embodied in the form of a general purpose computing device, which may be a server device, for example. Components of the electronic device 70 may include, but are not limited to: the at least one processor 71, the at least one memory 72, a bus 73 connecting the various system components, including the memory 72 and the processor 71.
Bus 73 includes a data bus, an address bus, and a control bus.
Memory 72 may include volatile memory such as Random Access Memory (RAM) 721 and/or cache memory 722, and may further include Read Only Memory (ROM) 723.
Memory 72 may also include a program tool 725 (or utility) having a set (at least one) of program modules 724, such program modules 724 including, but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment.
The processor 71 executes various functional applications and data processing, such as the battery state of health detection method in embodiment 1 described above, by running a computer program stored in the memory 72.
The electronic device 70 may also communicate with one or more external devices 74. Such communication may occur through an input/output (I/O) interface 75. Also, model-generated electronic device 70 may also communicate with one or more networks such as a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network such as the Internet via network adapter 76. As shown in fig. 10, the network adapter 76 communicates with other modules of the electronic device 70 over the bus 73. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with electronic device 70, including, but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, data backup storage systems, and the like.
It should be noted that although several units/modules or sub-units/modules of an electronic device are mentioned in the above detailed description, such a division is merely exemplary and not mandatory. Indeed, the features and functionality of two or more units/modules described above may be embodied in one unit/module in accordance with embodiments of the present disclosure. Conversely, the features and functions of one unit/module described above may be further divided into ones that are embodied by a plurality of units/modules.
Example 5
The present embodiment provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method of detecting a battery state of health in embodiment 1 described above.
More specifically, among others, readable storage media may be employed including, but not limited to: portable disk, hard disk, random access memory, read only memory, erasable programmable read only memory, optical storage device, magnetic storage device, or any suitable combination of the foregoing.
In a possible embodiment, the disclosure may also be implemented in the form of a program product comprising program code for causing a terminal device to carry out the steps of the detection method for battery state of health implementing the above-mentioned embodiment 1, when the program product is run on the terminal device.
Wherein the program code for carrying out the present disclosure may be written in any combination of one or more programming languages, and the program code may execute entirely on the user device, partly on the user device, as a stand-alone software package, partly on the user device, partly on a remote device or entirely on the remote device.
While specific embodiments of the present disclosure have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and the scope of the disclosure is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the disclosure, but such changes and modifications fall within the scope of the disclosure.
Claims (11)
1. A method for detecting a state of health of a battery, the method comprising:
acquiring an actual impedance value corresponding to sine wave excitation of a battery to be tested at a target frequency;
acquiring a theoretical impedance range value corresponding to the battery to be tested under the excitation of the sine wave of the target frequency;
detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value;
the target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency;
the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
2. The method according to claim 1, wherein the first target frequency is at least one of mid-frequency bands;
the second target frequency is at least one of the low frequency bands.
3. The method according to claim 1, wherein the step of obtaining a theoretical impedance range value corresponding to the battery to be measured under the sine wave excitation of the target frequency includes:
inputting sine wave excitation of the target frequency to a plurality of sample test batteries in a healthy state, and obtaining a corresponding sample impedance value of the sample test batteries under the sine wave excitation of the target frequency;
the theoretical impedance range value is derived based on a number of the sample impedance values.
4. The method according to claim 1, wherein the step of detecting the state of health of the battery to be measured based on the actual impedance value and the theoretical impedance range value includes:
training based on the theoretical impedance range value to obtain a preset battery state detection model;
and inputting the actual impedance value into the preset battery state detection model, and outputting the health state of the battery to be detected.
5. The method according to claim 1, wherein the step of detecting the state of health of the battery to be measured based on the actual impedance value and the theoretical impedance range value includes:
judging whether the actual impedance value accords with the theoretical impedance range value or not;
if yes, determining that the health state of the battery to be tested is healthy;
if not, determining that the health state of the battery to be tested is unhealthy.
6. The method according to any one of claims 1 to 5, wherein the step of obtaining an actual impedance value corresponding to the sine wave excitation of the battery to be measured at the target frequency includes:
generating sine wave excitation of the target frequency by taking a PWM wave as a carrier wave;
inputting the sine wave excitation to the battery to be tested, and obtaining the actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency;
and/or under different test parameters, acquiring the actual impedance value corresponding to the sine wave excitation of the battery to be tested at the target frequency.
7. The method according to claim 6, wherein the step of obtaining the actual impedance value corresponding to the sine wave excitation of the battery to be measured at the target frequency comprises:
acquiring a first impedance real part value and a first impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the first target frequency;
acquiring a second impedance real part value and a second impedance imaginary part value corresponding to the battery to be tested under the excitation of the sine wave of the second target frequency;
calculating the first actual impedance value based on the first impedance real value and the first impedance imaginary value;
and calculating the second actual impedance value based on the second impedance real value and the second impedance imaginary value.
8. A system for detecting a state of health of a battery, the system comprising:
the actual impedance acquisition module is used for acquiring an actual impedance value corresponding to sine wave excitation of the battery to be tested at the target frequency;
the theoretical impedance acquisition module is used for acquiring a theoretical impedance range value corresponding to the battery to be detected under the excitation of the sine wave of the target frequency;
the detection module is used for detecting the health state of the battery to be detected based on the actual impedance value and the theoretical impedance range value;
the target frequency comprises a first target frequency and a second target frequency, and the actual impedance value comprises a first actual impedance value corresponding to the first target frequency and a second actual impedance value corresponding to the second target frequency;
the first actual impedance value represents the electrochemical polarization process of the battery to be measured, and the second actual impedance value represents the concentration polarization process of the battery to be measured.
9. A battery system comprising the battery state of health detection system of claim 8.
10. An electronic device comprising a memory, a processor and a computer program stored on the memory for execution on the processor, wherein the processor implements the method of detecting a state of health of a battery as claimed in any one of claims 1-7 when executing the computer program.
11. A computer storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the method of detecting the state of health of a battery as claimed in any one of claims 1-7.
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