Electrochemical impedance spectroscopy-based method and apparatus for battery inspection of power systems

Abstract

The application discloses a kind of based on electrochemical impedance spectroscopy's power system battery group inspection method and device, belong to power system battery group detection field, comprising the following steps: pre-acquiring the reference electrochemical impedance spectroscopy of test battery group, then selecting same working condition, periodically carries out electrochemical impedance spectroscopy measurement to test battery group, obtains test electrochemical impedance spectroscopy;Finally, the deviation degree of test electrochemical impedance spectroscopy and reference electrochemical impedance spectroscopy is calculated, for judging the health condition of test battery group.The application can effectively save power system battery group operation and maintenance cost, improve detection efficiency and accuracy, timely master battery group internal deterioration, guarantee substation power system safe and stable operation.

Description

Technical Field

[0001] This invention relates to the field of power system battery pack testing, and more specifically, to a method and apparatus for power system battery pack inspection based on electrochemical impedance spectroscopy. Background Technology

[0002] Battery banks, as crucial backup power sources in power systems, typically consist of multiple individual batteries connected in series to form a 220V or 48V DC power supply system. In the event of a complete AC power outage at a substation, they continue to provide reliable power to electrical equipment, serving as the last line of defense for uninterrupted substation power. In recent years, several incidents have occurred where battery bank failures led to substation-wide power outages, highlighting the growing importance of online monitoring technologies for battery bank health.

[0003] Current online monitoring methods typically involve real-time acquisition and analysis of data such as terminal voltage, terminal temperature, and internal resistance of individual batteries. However, due to the large number of sensors and the complexity of the monitoring system, the investment cost is high, and installation and maintenance are time-consuming and labor-intensive. Furthermore, the impact of individual battery voltage, temperature, and internal resistance data on the overall health of the battery pack requires further research. Monitoring personnel often need to rely on their experience to analyze and judge the data, resulting in highly variable judgments. Battery electrochemical impedance spectroscopy (EIS) measurement is an important means of obtaining battery health status, but current devices, due to voltage limitations, can only perform EIS measurements on a single battery (or a few batteries in series), and cannot perform EIS detection on the entire battery pack during operation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and device for inspecting power system battery packs based on electrochemical impedance spectroscopy. This method and device can effectively save the operation and maintenance costs of power system battery packs, improve detection efficiency and accuracy, promptly grasp the internal deterioration of battery packs, and ensure the safe and stable operation of substation power systems.

[0005] The objective of this invention is achieved through the following solution:

[0006] A method for inspecting power system battery packs based on electrochemical impedance spectroscopy includes the following steps:

[0007] A reference electrochemical impedance spectroscopy of the battery pack under test is obtained in advance. Then, under the same operating conditions, the electrochemical impedance spectroscopy of the battery pack under test is periodically measured to obtain the test electrochemical impedance spectroscopy.

[0008] Finally, the deviation between the tested electrochemical impedance spectroscopy and the reference electrochemical impedance spectroscopy is calculated to determine the health status of the tested battery pack.

[0009] Furthermore, the acquisition of the reference electrochemical impedance spectroscopy (EIS) spectrum of the tested battery pack should be performed with a sufficiently long float charge time, and the voltage and current terminals of the battery pack EIS detection device should be electrically connected to the positive and negative electrodes of the tested battery pack, respectively; then, an amplitude of 0.05I is selected. 10 ~0.25I 10 A sinusoidal excitation current signal, with a test frequency of f1 to f2, is applied to the battery pack under test. Alternating voltage signals between the positive and negative electrodes of the battery pack are collected, and the impedance of the battery pack under different excitation signals is calculated to form an electrochemical impedance spectroscopy.

[0010] Furthermore, the step of periodically performing electrochemical impedance spectroscopy measurements on the tested battery pack under the same operating conditions includes the following sub-steps:

[0011] According to the operation and maintenance procedures for DC power supply devices in power systems, the test temperatures are compared before each test, and the temperature difference is controlled within the set range.

[0012] Then, check the historical charge and discharge data of the battery pack monitoring device to ensure that the operating conditions of the battery pack under test are consistent with the initial operating conditions, and avoid the equalization charging phase of routine maintenance.

[0013] Furthermore, the calculation of the deviation between the test electrochemical impedance spectroscopy and the reference electrochemical impedance spectroscopy includes the following sub-steps:

[0014] First, calculate the impedance difference ΔZi between the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum at the same frequency point;

[0015] Then plot the curve ΔZ(f) of the impedance difference as a function of frequency;

[0016] Then calculate the integral of the impedance difference function ΔZ(f) in the frequency band f1 to f2 to obtain the deviation.

[0017] Finally, the deviation calculated based on the detected electrochemical impedance spectroscopy is used to determine the internal electrochemical characteristics of the tested battery pack, thereby completing the assessment of the health status of the tested battery pack.

[0018] Furthermore, the calculation of the deviation between the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum includes the sub-step of determining the deviation between the test spectrum and the reference spectrum using shape-based distance or segment-based distance.

[0019] A power system battery pack inspection device based on electrochemical impedance spectroscopy, the device being used to perform the method described in any of the preceding claims, and further comprising an alternating current excitation source, an alternating voltage acquisition module, a clock synchronization module, a central processing unit, and a human-machine interaction module;

[0020] An alternating current excitation source is connected to the positive and negative terminals of the battery pack under test to apply sinusoidal currents of different frequencies.

[0021] The alternating voltage acquisition module is connected to the positive and negative terminals of the battery pack under test and is used to acquire the terminal voltage signal of the battery pack under test.

[0022] The clock synchronization module is connected to the alternating current excitation source and the alternating voltage acquisition module to ensure the synchronization of the alternating current signal and the alternating voltage signal.

[0023] The central processing unit interacts with the alternating current excitation source and the alternating voltage acquisition module to output operation instructions for the human-machine interaction module and receive real-time feedback signals. It stores the voltage and current data after signal conditioning and calculates the electrochemical impedance and curve deviation of the tested battery pack at each test frequency point.

[0024] The human-computer interaction module is connected to the central processing unit and is used to receive and translate the operator's operation instructions, as well as output relevant information to the operator.

[0025] Furthermore, it also includes dedicated test leads for connecting the battery pack under test to the alternating current excitation source and the alternating voltage acquisition device.

[0026] Furthermore, the alternating voltage acquisition module has a maximum voltage range of not less than 220V and has anti-interference function to suppress internal and external interference during the test process and ensure the accuracy of the acquired alternating voltage signal.

[0027] Furthermore, the central processing unit also has self-testing and protection functions, used to verify whether the test wiring is correct, and to issue warnings and protection commands to stop the test in case of abnormalities during the test.

[0028] Furthermore, the human-computer interaction module also includes a display, control software, and data processing software.

[0029] The beneficial effects of this invention include:

[0030] This invention overcomes the problem of being unable to perform group measurements by optimizing and improving existing electrochemical impedance spectroscopy (EIS) schemes. Utilizing the ability of EIS curves to sensitively characterize the health status of tested battery packs, the obtained test spectra are compared with reference spectra, and the deviation of the test spectrum curves is calculated, thereby completing the assessment of the health status of the tested battery packs. Using the device of this invention, periodic inspections of multiple battery packs can be carried out simultaneously. The operation is simple and intuitive, allowing staff to quickly master its application. Simultaneously, this invention can effectively save on the operation and maintenance costs of power system battery packs, improve testing efficiency and accuracy, promptly grasp the internal deterioration of battery packs, and ensure the safe and stable operation of substation power systems.

[0031] This invention solves the shortcomings of existing online monitoring systems for battery packs, such as high cost, time-consuming and labor-intensive installation and maintenance, and large dispersion of judgment results, as well as the technical problem that existing electrochemical impedance spectroscopy instruments cannot perform group measurements. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of a battery pack electrochemical impedance spectroscopy testing method according to an embodiment of the present invention;

[0034] Figure 2 This is a structural diagram of a battery pack electrochemical impedance spectroscopy testing device according to an embodiment of the present invention;

[0035] Figure 3 This is a flowchart illustrating the operation of a battery pack electrochemical impedance spectroscopy testing device according to an embodiment of the present invention.

[0036] Figure 4 This is a comparison diagram of the reference spectrum and the test spectrum according to an embodiment of the present invention;

[0037] Figure 5 This is an impedance difference curve of one embodiment of the present invention. Detailed Implementation

[0038] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0039] Example 1

[0040] S1. Select a newly commissioned battery pack and, with a sufficiently long float charging time, perform electrochemical impedance spectroscopy measurements on the battery pack to obtain a reference spectrum for the battery pack.

[0041] like Figure 2 As shown, the voltage and current terminals of the battery pack electrochemical impedance spectroscopy detection device are electrically connected to the positive and negative electrodes of the battery pack under test, respectively; an amplitude of 0.05I is selected. 10 ~0.25I 10A sinusoidal excitation current signal, with a test frequency of f1 to f2, is applied to the battery pack under test. Alternating voltage signals between the positive and negative electrodes of the battery pack are collected, and the impedance of the battery pack under different excitation signals is calculated to form an electrochemical impedance spectroscopy.

[0042] S2. During the subsequent operation of the tested battery pack, the same operating conditions are selected, and the electrochemical impedance spectroscopy of the tested battery pack is periodically measured as the test spectrum.

[0043] According to the operation and maintenance procedures for DC power supply devices in power systems, the temperature inside the DC power supply panel should be kept constant. Before each test, the test temperatures should be compared and the difference should not be too large. Historical charge and discharge data of the monitoring device of the battery pack under test should be consulted. In order to ensure that the operating conditions of the battery pack under test are consistent with the initial operating conditions and to avoid the equalization charging phase of routine maintenance, the test should be carried out after at least 48 hours of float charging.

[0044] S3, calculate the deviation between the test spectrum and the reference spectrum to determine the health status of the tested battery pack.

[0045] Figure 4 The reference spectrum and the test spectrum curves are plotted. Since the frequency point of each test is fixed, the impedance difference ΔZi between the test spectrum and the reference spectrum at the same frequency point can be calculated, and the curve ΔZ(f) of the impedance difference as a function of frequency can be plotted. Figure 5 The impedance difference curve is plotted, and the deviation is obtained by calculating the integral of the impedance difference function ΔZ(f) in the frequency band f1 to f2. Electrochemical impedance spectroscopy can sensitively reflect the complex electrochemical characteristics inside the tested battery pack. If the tested battery pack is in good health, the deviation S should be close to 0. If deterioration occurs, the deviation S should change significantly compared with the previous test data, thus completing the judgment of the health status of the tested battery pack.

[0046] Example 2

[0047] Alternatively, the deviation of the test spectrum from the reference spectrum can also be determined using methods such as shape-based distance or segment-based distance, and is not limited to this embodiment.

[0048] This embodiment, based on Embodiment 1, provides a battery pack detection device based on electrochemical impedance spectroscopy, such as... Figures 2-3 As shown, it includes an alternating current excitation source, an alternating voltage acquisition module, a clock synchronization module, a central processing unit, and a human-machine interaction module, wherein:

[0049] An alternating current excitation source is connected to the positive and negative terminals of the battery pack under test to apply small-amplitude sinusoidal currents of different frequencies.

[0050] The alternating voltage acquisition device is connected to the positive and negative terminals of the battery pack under test and is used to acquire the terminal voltage signal of the battery pack under test.

[0051] The clock synchronization module is connected to the alternating current excitation source and the alternating voltage acquisition unit to ensure good synchronization between the alternating current signal and the alternating voltage signal.

[0052] The central processing unit interacts with the alternating current excitation source and alternating voltage acquisition unit to output operation instructions for the human-machine interface module and receive real-time feedback signals. It stores the voltage and current data after signal conditioning and calculates the electrochemical impedance and curve deviation of the tested battery pack at each test frequency point.

[0053] The human-computer interaction module is connected to the central processing unit and is used to receive and translate the operator's operation instructions, as well as output relevant information to the operator.

[0054] The aforementioned battery pack testing device using electrochemical impedance spectroscopy also includes dedicated test leads for connecting the battery pack under test to an alternating current excitation source and an alternating voltage acquisition device.

[0055] The alternating voltage acquisition device has a maximum voltage range of no less than 220V and is equipped with anti-interference function to suppress internal and external interference during the test process and ensure the accuracy of the acquired alternating voltage signal.

[0056] The central processing unit also has self-testing and protection functions, which are used to verify whether the test wiring is correct, and to issue warnings and protection commands to stop the test in case of abnormalities during the test.

[0057] The human-computer interaction module also includes a display, control software, and data processing software.

[0058] like Figure 3 As shown, the working process of the battery pack electrochemical impedance spectroscopy testing device is as follows:

[0059] Connect the device correctly to the battery pack under test, and set the test current amplitude to 0.05I. 10 ~0.25I 10 Set the test frequency f1 to f2, start collecting test spectrum data, calculate the impedance difference ΔZi between the test spectrum and the reference spectrum at the same frequency point, plot the curve ΔZ(f) of impedance difference with frequency, calculate the deviation S, and judge the health status of the tested battery pack based on the magnitude of the deviation.

[0060] It should be noted that, within the scope of protection defined in the claims of this invention, the following embodiments can be combined and / or extended or replaced in any logical manner from the above specific embodiments, such as the disclosed technical principles, disclosed technical features or implicitly disclosed technical features.

[0061] The units described in the embodiments of the present invention can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0062] According to one aspect of the present invention, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and executes the computer instructions, causing the computer device to perform the methods provided in the various optional implementations described above.

[0063] In another aspect, embodiments of the present invention also provide a computer-readable medium, which may be included in the electronic device described in the above embodiments; or it may exist independently and not assembled into the electronic device. The computer-readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to perform the methods described in the above embodiments.

[0064] All parts not covered in this invention are the same as or can be implemented using existing technologies.

[0065] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and are not restrictive.

[0066] In addition to the examples above, other embodiments may be obtained by those skilled in the art based on the above disclosure or by making modifications using knowledge or technology in related fields. The features of each embodiment may be interchanged or replaced. Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for inspecting a power system battery bank based on electrochemical impedance spectroscopy, the method comprising: The method comprises the following steps: obtaining a reference electrochemical impedance spectrum of the test battery pack in advance, periodically measuring the electrochemical impedance spectrum of the test battery pack under the same working condition to obtain a test electrochemical impedance spectrum, and calculating the deviation degree of the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum to determine the health condition of the test battery pack; the calculation of the deviation degree of the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum comprises the following steps: first, calculating the impedance difference ΔZi of the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum at the same frequency point; then, drawing a curve ΔZ(f) of the impedance difference with respect to the frequency; finally, judging the electrochemical characteristics inside the test battery pack based on the deviation degree calculated from the detected electrochemical impedance spectrum, thereby completing the determination of the health condition of the test battery pack. The integral of the impedance difference function ΔZ(f) in the frequency band f1~f2 is recalculated, i.e. the deviation degree is obtained ; The reference electrochemical impedance spectrum of the test battery pack is obtained under the condition that the float time is long enough, and the voltage and current terminals of the battery pack electrochemical impedance spectrum detection device are respectively connected to the positive and negative electrodes of the test battery pack.

2. The electrochemical impedance spectroscopy based power system battery bank inspection method of claim 1, wherein, The periodic measurement of the electrochemical impedance spectrum of the test battery pack under the same working condition comprises the following steps: The amplitude of the sinusoidal excitation current signal is 0.05I 10 The amplitude of the sinusoidal excitation current signal is 0.25I 10 The sinusoidal excitation current signal with an amplitude of 0.05I~0.25I is applied to the test battery, the alternating voltage signals of the positive and negative electrodes of the battery are collected, the impedances of the battery under different frequency excitation signals are calculated, and the electrochemical impedance detection map is formed.

3. The electrochemical impedance spectroscopy based power system battery bank inspection method of claim 1, wherein, before each test, compare the test temperature according to the operation and maintenance regulations of the direct current power supply device for power systems, and control the temperature difference within a set range; then, query the historical charge and discharge data of the test battery pack monitoring device to ensure that the working condition of the test battery pack is consistent with the initial working condition and avoid the equalization charging phase of routine maintenance. The calculation of the deviation degree of the test electrochemical impedance spectrum and the reference electrochemical impedance spectrum comprises the following steps: judging the curve deviation degree of the test spectrum and the reference spectrum by using shape-based distance or using piecewise-based distance.

4. The electrochemical impedance spectroscopy based power system battery bank inspection method of claim 1, wherein, The device is used to execute the method according to any one of claims 1-4, and further comprises an alternating current excitation source, an alternating voltage acquisition module, a clock synchronization module, a central processing unit, and a human-computer interaction module.

5. An electrochemical impedance spectroscopy based power system battery pack inspection device, characterized in that, The alternating current excitation source is connected to the positive and negative electrodes of the test battery pack to apply sinusoidal current of different frequencies. The alternating voltage acquisition module is connected to the positive and negative electrodes of the test battery pack to acquire the terminal voltage signal of the test battery pack. The clock synchronization module is connected to the alternating current excitation source and the alternating voltage acquisition module to ensure the synchronization of the alternating current signal and the alternating voltage signal. The central processing unit interacts with the alternating current excitation source and the alternating voltage acquisition module to output the operation instruction of the human-computer interaction module and receive the real-time feedback signal, store the voltage and current data after signal conditioning, and calculate the electrochemical impedance and curve deviation degree of the test battery pack at each test frequency point. The human-computer interaction module is connected to the central processing unit to receive and translate the operation instruction of the operator, and output relevant information to the operator. The device further comprises a special test lead for connecting the test battery pack to the alternating current excitation source and the alternating voltage acquisition module.

6. The electrochemical impedance spectroscopy based power system battery pack inspection device of claim 5, wherein, The maximum voltage range of the alternating voltage acquisition module is not less than 220V, and it has an anti-interference function to suppress internal and external interference during the test and ensure the accuracy of the acquired alternating voltage signal.

7. The electrochemical impedance spectroscopy based power system battery pack inspection device of claim 5, wherein, ​ 8. The electrochemical impedance spectroscopy based power system battery pack inspection device of claim 5, wherein, The central processor is also provided with self-checking and protection functions, which are used for checking whether the test connection is correct, and giving a pre-warning and a protection instruction to stop the detection when an abnormal condition occurs in the detection process.

9. The electrochemical impedance spectroscopy based power system battery pack inspection device of claim 5, wherein, The human-computer interaction module further comprises a display, control software and data processing software.

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