Storage battery health state correction method based on impedance spectrum

Abstract

The invention provides a storage battery health state correction method based on an impedance spectrum. The method comprises the following steps: acquiring a capacity value measured for the first time and a capacity value, a discharge depth and a reference impedance spectrum parameter measured for the second time of the storage battery; obtaining a reference health state index through the capacity value and the discharge depth; acquiring an impedance spectrum parameter of the storage battery in a new period; obtaining the impedance variable quantity of the reference impedance spectrum parameter through the impedance spectrum parameter of the storage battery in the new period and the impedance spectrum parameter of the storage battery measured for the second time; and obtaining the corrected health state of the battery through the variable quantity of the impedance spectrum parameter. The method has the advantages that normal operation of the battery does not need to be interrupted, the system can continuously monitor the health state of the battery, continuous and dynamic health state evaluation is provided for the battery in practical application, and the defects of a traditional off-line capacity checking test are effectively overcome.

Description

Technical Field

[0001] The invention relates to the field of battery state correction, and in particular to a battery health state correction method based on impedance spectrum. Background Art

[0002] As an important emergency backup power source, batteries are widely used in power systems. At critical power consumption moments, the normal operation and operation of important equipment are guaranteed. Under normal circumstances, the battery is in an online floating charge state. It is necessary to understand the health of the battery, that is, the health or health state, to ensure that it can play its due role at critical power consumption moments. The battery's state of health (State of Health, referred to as SOH) refers to the ratio of the energy released by the battery from a full state at a certain rate to the cut-off voltage under standard conditions to its corresponding nominal rated energy, usually expressed as a percentage. When the SOH drops below 80%, it is necessary to consider replacing the battery. Under normal circumstances, the battery is in an online floating charge state, and the battery's voltage, temperature, current, internal resistance and other parameters can be monitored. In order to realize online evaluation of the battery health status, the industry has many methods for evaluating the battery health status based on the SOH definition, or the battery's chemical model and circuit model, such as traditional offline methods, data-driven methods, fusion model methods, etc., to conduct qualitative or quantitative analysis of the battery's health status.

[0003] The simplest and most direct traditional offline method with the highest accuracy is to define the discharge capacity according to SOH, which can accurately measure the health status of the battery. That is, the battery is first fully charged, and then discharged to the cut-off voltage at the rated power. The ratio of the discharged power to the nominal rated power is the battery SOH measured this time. However, accurate discharge method SOH testing requires offline operation and can only be used as a capacity calibration and annual maintenance capacity verification work item.

[0004] Another traditional offline method is the open circuit voltage method, which estimates SOH based on the known correspondence between the battery open circuit voltage OCV and the state of charge SOC. However, it also requires the battery to be in an offline state and is not suitable for online estimation. Data-driven methods include the Kalman filter method and the black box estimation method, which are based on algorithms such as the autoregressive Kalman filter estimation model, support vector machine (SVM), relevance vector machine (RVM) and artificial neural network (ANN) to achieve battery health status estimation, but the calculation is large and the algorithm is complex.

[0005] The fusion model method is a new SOH estimation method that integrates several battery models or estimation methods. It is increasingly valued by researchers. Its purpose is to maximize the advantages of two different models, overcome their respective shortcomings, and improve estimation accuracy. However, various models are usually very complex and difficult to integrate, and there is a lack of simple and effective analysis methods for the aging process. Summary of the invention

[0006] The purpose of the present invention is to overcome the current common problems such as offline operation limitations, high computational complexity or fusion difficulties. Therefore, a battery health status correction method based on impedance spectroscopy is proposed to achieve real-time online monitoring of the battery. Without interrupting the normal operation of the battery, the system can continuously monitor the health status of the battery and obtain the electrochemical characteristics inside the battery without interfering with the battery operation. This non-destructive testing method will not have a negative impact on the normal use of the battery, ensuring the stability and safety of the system.

[0007] The present application proposes a battery health status correction method based on impedance spectroscopy, comprising the following steps:

[0008] Step 1, obtaining the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the discharge depth and the reference impedance spectrum parameters;

[0009] Step 2, obtaining a baseline health status index through capacity value and discharge depth;

[0010] Step 3, obtaining impedance spectrum parameters of the battery in the new cycle;

[0011] Step 4, obtaining the impedance change of the reference impedance spectrum parameter by using the impedance spectrum parameter of the battery in the new cycle and the impedance spectrum parameter measured for the battery for the second time;

[0012] Step 5, obtaining the corrected battery health status through the change of impedance spectrum parameters.

[0013] The beneficial effects are as follows:

[0014] Without interrupting the normal operation of the battery, the system can continuously monitor the health status of the battery, which provides a continuous and dynamic health status assessment for the battery in practical applications, effectively avoiding the shortcomings of traditional offline nuclear capacity testing. Since this method does not require additional external equipment or frequency response analysis instruments, the entire measurement and analysis process is completed by the battery monitoring unit, which greatly reduces the cost of system operation and maintenance. Compared with traditional expensive offline testing equipment, this embedded monitoring technology is more economical and efficient, and can obtain the electrochemical characteristics of the battery without interfering with the operation of the battery. This non-destructive testing method will not have a negative impact on the normal use of the battery, ensuring the stability and safety of the system.

[0015] Preferably, obtaining the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the depth of discharge and the reference impedance spectrum parameter also includes:

[0016] Obtain the impedance spectrum parameters measured for the battery for the first time.

[0017] Preferably, the impedance spectrum parameters include the ohmic internal resistance, polarization internal resistance, and polarization capacitance of the battery.

[0018] Preferably, obtaining a reference health status index through capacity value and discharge depth includes:

[0019] The baseline health status index is calculated by the following formula:

[0020]

[0021] Among them, Q rate Q is the capacity value measured for the battery for the first time. aged It is the capacity value measured for the battery for the second time. DOD is the depth of discharge, which indicates the preset ratio of discharge to the total power.

[0022] Preferably, the impedance variation of the reference impedance spectrum parameter obtained by measuring the impedance spectrum parameter of the battery in the new cycle and the impedance spectrum parameter of the battery for the second time comprises:

[0023] Convert the frequency domain expression of the second impedance spectrum parameters into the time domain expression:

[0024] The time domain expression is:

[0025]

[0026] Among them, Z ω is the spectrum impedance, C s1 The second time to measure the impedance spectrum parameters of the battery to obtain the polarization capacitance, R C1 The second time to measure the impedance spectrum parameters of the battery to obtain the ohmic internal resistance, R S1 To measure the impedance spectrum parameters of the battery for the second time and obtain the polarization resistance;

[0027] The time domain matrix is ​​expressed as:

[0028] Z = [Rcref Rsref Csref];

[0029] Where Z is the time domain impedance, C sref The second time to measure the impedance spectrum parameters of the battery to obtain the reference polarization capacitance, R Cref The second time to measure the impedance spectrum parameters of the battery to obtain the benchmark ohmic internal resistance, R Sref To measure the impedance spectrum parameters of the battery for the second time and obtain the reference polarization resistance;

[0030] The impedance spectrum parameters of the battery in the new cycle are converted into time domain parameters, and the impedance spectrum parameters of the battery in the new cycle and the impedance spectrum parameters measured for the battery for the second time are calculated to obtain the change formula of the benchmark impedance spectrum parameters:

[0031] ΔZ=[(Rc-Rcref) (Rs-Rsref) (Cs-Csref)];

[0032] Where ΔZ is the impedance change in the time domain, C S The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization capacitance, R C The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization internal resistance, R S The impedance spectrum parameters of the battery are measured in a new cycle to obtain a reference ohmic resistance.

[0033] Preferably, obtaining the corrected battery health status through the change in impedance spectrum parameters includes:

[0034] The influence factors of battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status are calculated;

[0035] The aging correction factor is calculated by the influence factors of the battery's ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery's health status and the impedance change;

[0036] The corrected battery health status is obtained by calculating the aging correction factor.

[0037] Preferably, the calculated influencing factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health state include:

[0038] Repeat steps 1 and 2. The calculation formula for the battery ohmic internal resistance influence factor is as follows:

[0039]

[0040] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R ci is the ohmic internal resistance obtained from the i-th battery measurement, β Rc is the ohmic internal resistance influence factor obtained from the i-th battery measurement;

[0041] The calculation formula of the battery polarization internal resistance influence factor is as follows:

[0042]

[0043] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R Si is the polarization internal resistance obtained from the i-th battery measurement, β Sc is the ohmic internal resistance influence factor obtained from the i-th battery measurement;

[0044] The calculation formula of the battery polarization capacitance influencing factor is as follows:

[0045]

[0046] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, C Si is the polarization capacitance obtained from the i-th battery measurement, β CS is the polarization capacitance influence factor obtained from the i-th battery measurement;

[0047] The battery aging influence factor is obtained by the influence factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status. The formula is as follows:

[0048]

[0049] Where β is the battery aging factor.

[0050] Preferably, the aging correction factor is calculated by the influence factors of the battery's ohmic internal resistance, polarization internal resistance, and polarization capacitance on the battery's health status and the impedance change, including:

[0051] The battery aging influencing factor is normalized to obtain the aging correction factor;

[0052] The formula is as follows:

[0053] γ=f(β).

[0054] Preferably, the corrected battery health status obtained by calculating the aging correction factor includes:

[0055] Calculated by the following formula:

[0056] SOH cor =γ·SOH ref =f(β)SOH ref ;

[0057] Among them, SOH cor is the corrected battery health status.

[0058] Preferably, it also includes: presetting the deviation alarm value b of the impedance spectrum parameter RC , b RS and b CS , calculate the deviation value a of the impedance spectrum parameter RC 、a RS and a CS , the formula is as follows:

[0059]

[0060] a RC is the battery ohmic internal resistance deviation value;

[0061]

[0062] a RS is the battery polarization internal resistance deviation value;

[0063]

[0064] a CS is the battery polarization capacitance deviation value;

[0065] According to the deviation value a RC 、a RS and a CS Set and deviation alarm value b RC , b RS and b CS Compare and make alarm judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a schematic diagram of the block diagram structure of the present invention;

[0067] Figure 2 It is a schematic diagram of an equivalent circuit of a storage battery of the present invention. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0069] Combined with Figure 1 The present application proposes a battery health status correction method based on impedance spectroscopy, comprising the following steps:

[0070] Step 1, obtaining the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the discharge depth and the reference impedance spectrum parameters;

[0071] As a further preferred embodiment, the impedance spectrum parameters include the ohmic internal resistance, polarization internal resistance, and polarization capacitance of the battery.

[0072] Specifically, the impedance spectrum parameters measured for the battery for the first time are obtained to provide a benchmark value for subsequent aging analysis and health status correction. The initial impedance spectrum parameters are used as a reference for subsequent measurement data to compare the impedance increment that changes over time.

[0073] As a further preferred embodiment, obtaining the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the depth of discharge and the reference impedance spectrum parameter further includes:

[0074] Obtain the impedance spectrum parameters measured for the battery for the first time.

[0075] Specifically, during the initial use stage of the battery, the first capacity value of the battery is obtained by measurement;

[0076] After the battery has been used for a period of time, a second capacity measurement is performed to obtain a second capacity value;

[0077] At the same time, the discharge depth (DOD) of each measurement is obtained to ensure the accuracy of capacity measurement;

[0078] The benchmark impedance spectrum parameters include: ohmic internal resistance (Rc), polarization internal resistance (Rs) and polarization capacitance (Cs), which are used to establish the benchmark reference values ​​of the battery aging process.

[0079] In some embodiments, in combination Figure 2 By setting the BMU detection unit to measure the real and imaginary impedance data of the battery under the characteristic frequency excitation signal, the ohmic internal resistance, polarization internal resistance and polarization capacitance of the battery are calculated according to the Thevenin equivalent circuit of the battery.

[0080] Step 2, obtaining a baseline health status index through capacity value and discharge depth;

[0081] As a further preferred embodiment, obtaining a reference health status index through the capacity value and the discharge depth includes:

[0082] The baseline health status index is calculated by the following formula:

[0083]

[0084] Among them, Q rate Q is the capacity value measured for the battery for the first time. aged It is the capacity value measured for the battery for the second time. DOD is the depth of discharge, which indicates the preset ratio of discharge to the total power.

[0085] Specifically, the capacity is standardized by introducing the depth of discharge DOD. If the battery is not fully discharged, the partial discharge is normalized to the full capacity state through this ratio, thereby obtaining an accurate health status.

[0086] For example: If Q rate The battery capacity is 100Ah, indicating that the initial capacity of the battery is 100Ah. The second measured depth of discharge DOD is 0.9 (i.e. the battery is discharged 90% during the measurement). The measured discharge capacity Q aged 80Ah, which means that the battery capacity after aging is 80Ah after 90% discharge. Then the baseline health status index SOH ref Calculated as:

[0087]

[0088] This indicates that the battery health state is maintained at approximately 88.8% relative to the initial capacity.

[0089] Step 3, obtaining impedance spectrum parameters of the battery in the new cycle;

[0090] Steps 1 and 2 are only the basis for determining the battery health status. The new cycle represents the need to measure the battery health status when the battery is in working condition.

[0091] Step 4, obtaining the impedance change of the reference impedance spectrum parameter by using the impedance spectrum parameter of the battery in the new cycle and the impedance spectrum parameter measured for the battery for the second time;

[0092] As a further preferred embodiment, the impedance variation of the reference impedance spectrum parameter obtained by measuring the impedance spectrum parameter of the battery in the new cycle and the impedance spectrum parameter of the battery for the second time includes:

[0093] Convert the frequency domain expression of the second impedance spectrum parameters into the time domain expression:

[0094] The time domain expression is:

[0095]

[0096] Among them, Z ω is the spectrum impedance, C s1 The second time to measure the impedance spectrum parameters of the battery to obtain the polarization capacitance, R C1 The second time to measure the impedance spectrum parameters of the battery to obtain the ohmic internal resistance, R S1 To measure the impedance spectrum parameters of the battery for the second time and obtain the polarization resistance;

[0097] The time domain matrix is ​​expressed as:

[0098] Z = [Rcref Rsref Csref];

[0099] Where Z is the time domain impedance, C srefThe second time to measure the impedance spectrum parameters of the battery to obtain the reference polarization capacitance, R Cref The second time to measure the impedance spectrum parameters of the battery to obtain the benchmark ohmic internal resistance, R Sref To measure the impedance spectrum parameters of the battery for the second time and obtain the reference polarization resistance;

[0100] The impedance spectrum parameters of the battery in the new cycle are converted into time domain parameters, and the impedance spectrum parameters of the battery in the new cycle and the impedance spectrum parameters measured for the battery for the second time are calculated to obtain the change formula of the benchmark impedance spectrum parameters:

[0101] ΔZ=[(Rc-Rcref) (Rs-Rsref) (Cs-Csref)];

[0102] Where ΔZ is the impedance change in the time domain, C S The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization capacitance, R C The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization internal resistance, R S The impedance spectrum parameters of the battery are measured in a new cycle to obtain a reference ohmic resistance.

[0103] Among them, the ohmic internal resistance Rc represents the battery connection resistance, diaphragm resistance, electrolyte resistance, joint surface resistance, etc. The corrosion of poles and busbars, loose connections, battery water loss, lead-acid battery plate sulfation, etc. will lead to an increase in ohmic internal resistance, which is the main factor of battery aging parameters;

[0104] Polarization internal resistance Rs includes the electrochemical polarization internal resistance and concentration polarization internal resistance of the battery, which characterizes the internal resistance formed when the electrode material loses electrons and undergoes oxidation reaction during the battery charging and discharging process. Changes in battery electrolyte, plate sulfation, diaphragm problems, etc. will change the resistance to charge and discharge ion flow, usually leading to an increase in polarization internal resistance;

[0105] Polarization capacitance Cs is the double-layer capacitance formed by the parallel assembly of positive and negative plates, which represents the charge transfer on the electrode interface and the charge separation of the electrolyte solution. The electrode material, electrolyte concentration, electrolyte type and temperature will affect the value of polarization capacitance.

[0106] Step 5, obtaining the corrected battery health status through the change of impedance spectrum parameters.

[0107] As a further preferred embodiment, obtaining the corrected battery health status through the change in impedance spectrum parameters includes:

[0108] The influence factors of battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status are calculated;

[0109] The aging correction factor is calculated by the influence factors of the battery's ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery's health status and the impedance change;

[0110] The corrected battery health status is obtained by calculating the aging correction factor.

[0111] As a further preferred embodiment, the calculated influencing factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health state include:

[0112] Repeat steps 1 and 2. The calculation formula for the battery ohmic internal resistance influence factor is as follows:

[0113]

[0114] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R ci is the ohmic internal resistance obtained from the i-th battery measurement, β Rc is the ohmic internal resistance influence factor obtained from the i-th battery measurement;

[0115] The calculation formula of the battery polarization internal resistance influence factor is as follows:

[0116]

[0117] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R Si is the polarization internal resistance obtained from the i-th battery measurement, β Sc is the ohmic internal resistance influence factor obtained from the i-th battery measurement;

[0118] The calculation formula of the battery polarization capacitance influencing factor is as follows:

[0119]

[0120] Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, C Si is the polarization capacitance obtained from the i-th battery measurement, β CS is the polarization capacitance influence factor obtained from the i-th battery measurement;

[0121] The battery aging influence factor is obtained by the influence factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status. The formula is as follows:

[0122]

[0123] Where β is the battery aging factor.

[0124] Specifically, the above embodiment only performs one resistance and capacitance measurement (second measurement). In this embodiment, resistance and capacitance measurements can be performed multiple times to obtain SOH, and steps 1-2 can be repeated to improve the accuracy. The least squares method is used to determine the influence factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the health status of the battery according to the experimental data;

[0125] The impact factor is obtained by the following method, β RC For example;

[0126] To find the ohmic internal resistance R c Factor affecting SOH β Rc , we first define an error function, which represents the sum of squared deviations between the actual SOH value and the fitted SOH value:

[0127]

[0128] in:

[0129] SOH i is the health status of the battery detected at the ith time;

[0130] β Rc is the influencing factor of the ohmic internal resistance we want to calculate;

[0131] R ci is the ohmic internal resistance of the battery tested for the i-th time;

[0132] The second ohmic internal resistance obtained in step 1 of this application;

[0133] In order to find the optimal β Rc , we need to modify the error function Q(β Rc ) for β Rc To find the derivative and make it equal to 0, the process is as follows:

[0134]

[0135] After sorting, we get:

[0136]

[0137] As a further preferred embodiment, the aging correction factor is calculated by the influence factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health state and the impedance change, including:

[0138] The battery aging influencing factor is normalized to obtain the aging correction factor;

[0139] The formula is as follows:

[0140] γ=f(β).

[0141] As a further preferred embodiment, the corrected battery health status obtained by calculating the aging correction factor includes:

[0142] Calculated by the following formula:

[0143] SOH cor =γ·SOH ref =f(β)SOH ref ;

[0144] Among them, SOH cor is the corrected battery health status.

[0145] As a further preferred embodiment, it also includes:

[0146] Preset impedance spectrum parameter deviation alarm value b RC , b RS and b CS , calculate the deviation value a of the impedance spectrum parameter RC 、a RS and a CS , the formula is as follows:

[0147]

[0148] a RC is the battery ohmic internal resistance deviation value;

[0149]

[0150] a RS is the battery polarization internal resistance deviation value;

[0151]

[0152] a CS is the battery polarization capacitance deviation value;

[0153] According to the deviation value a RC 、a RS and a CS Set and deviation alarm value b RC , b RS and b CS Compare and judge the alarm. The judgment logic is as follows:

[0154]

[0155] When the deviation value a RC Greater than or equal to b RC Warning, when the deviation value a RC Less than b RC normal;

[0156]

[0157] When the deviation value a RS Greater than or equal to b RS Warning, when the deviation value a RS Less than b RS normal;

[0158]

[0159] When the deviation value a CS Less than or equal to b CS Warning, when the deviation value a CS Greater than b CS normal;

[0160] In specific implementation, b RC , b RS and b CS It can be set based on experience. For example, if the actual internal resistance of the battery exceeds 50%, it cannot discharge. You can set the incremental limit of multiple parameters of the battery to 50%. If the limit is exceeded, the BMS will remind the battery of abnormality and the operation and maintenance personnel need to pay attention and take measures.

[0161] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention described herein. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A battery health status correction method based on impedance spectroscopy, It is characterized in that The steps include: Step 1, obtaining the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the discharge depth and the reference impedance spectrum parameters; Step 2, obtaining a baseline health status index through capacity value and discharge depth; Step 3, obtaining impedance spectrum parameters of the battery in the new cycle; Step 4, obtaining the impedance change of the reference impedance spectrum parameter by using the impedance spectrum parameter of the battery in the new cycle and the impedance spectrum parameter measured for the battery for the second time; Step 5, obtaining the corrected battery health status through the change of impedance spectrum parameters.

2. The method according to claim 1, It is characterized in that Acquiring the capacity value measured for the battery for the first time and the capacity value measured for the battery for the second time, the discharge depth and the reference impedance spectrum parameters also includes: Obtain the impedance spectrum parameters measured for the battery for the first time.

3. The method according to claim 2, It is characterized in that The impedance spectrum parameters include the ohmic internal resistance, polarization internal resistance, and polarization capacitance of the battery.

4. The method according to claim 1, It is characterized in that The baseline health status index obtained by capacity value and discharge depth includes: The baseline health status index is calculated by the following formula: Among them, Q rate Q is the capacity value measured for the battery for the first time. aged It is the capacity value measured for the battery for the second time. DOD is the depth of discharge, which indicates the preset ratio of discharge to the total power.

5. The method according to claim 1, It is characterized in that The impedance variation of the reference impedance spectrum parameters obtained by measuring the impedance spectrum parameters of the battery in the new cycle and the impedance spectrum parameters of the battery for the second time includes: Convert the frequency domain expression of the second impedance spectrum parameters into the time domain expression: The time domain expression is: Among them, Z ω is the spectrum impedance, C s1 The second time to measure the impedance spectrum parameters of the battery to obtain the polarization capacitance, R C1 The second time to measure the impedance spectrum parameters of the battery to obtain the ohmic internal resistance, R S1 To measure the impedance spectrum parameters of the battery for the second time and obtain the polarization resistance; The time domain matrix is ​​expressed as: Z = [Rcref Rsref Csref]; Where Z is the time domain impedance, C sref The second time to measure the impedance spectrum parameters of the battery to obtain the reference polarization capacitance, R Cref The second time to measure the impedance spectrum parameters of the battery to obtain the benchmark ohmic internal resistance, R Sref To measure the impedance spectrum parameters of the battery for the second time and obtain the reference polarization resistance; The impedance spectrum parameters of the battery in the new cycle are converted into time domain parameters. The method is the same as above. The impedance spectrum parameters of the battery in the new cycle and the impedance spectrum parameters measured for the battery for the second time are calculated to obtain the change formula of the benchmark impedance spectrum parameters: ΔZ=[(Rc-Rcref) (Rs-Rsref) (Cs-Csref)]; Where ΔZ is the impedance change in the time domain, C s The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization capacitance, R C The impedance spectrum parameters of the battery are measured in the new cycle to obtain the reference polarization internal resistance, R S The impedance spectrum parameters of the battery are measured in a new cycle to obtain a reference ohmic resistance.

6. The method according to claim 1, It is characterized in that The corrected battery health status obtained by the change in impedance spectrum parameters includes: The influence factors of battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status are calculated; The aging correction factor is calculated by the influence factors of the battery's ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery's health status and the impedance change; The corrected battery health status is obtained by calculating the aging correction factor.

7. The method according to claim 6, It is characterized in that The factors affecting the battery health status calculated by the ohmic internal resistance, polarization internal resistance and polarization capacitance include: Repeat steps 1 and 2. The calculation formula for the battery ohmic internal resistance influence factor is as follows: Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R ci is the ohmic internal resistance obtained from the i-th battery measurement, β Rc is the ohmic internal resistance influence factor obtained from the i-th battery measurement; The calculation formula of the battery polarization internal resistance influence factor is as follows: Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, R Si is the polarization internal resistance obtained from the i-th battery measurement, β Sc is the ohmic internal resistance influence factor obtained from the i-th battery measurement; The calculation formula of the battery polarization capacitance influencing factor is as follows: Among them, SOH i is the baseline health status index obtained from the i-th battery measurement, C Si is the polarization capacitance obtained from the i-th battery measurement, β CS is the polarization capacitance influence factor obtained from the i-th battery measurement; The battery aging influence factor is obtained by the influence factors of the battery ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery health status. The formula is as follows: Where β is the battery aging factor.

8. The method according to claim 7, It is characterized in that The aging correction factors are calculated by the influence factors of the battery's ohmic internal resistance, polarization internal resistance and polarization capacitance on the battery's health status and the impedance change, including: The battery aging influencing factor is normalized to obtain the aging correction factor; The formula is as follows: γ=f(β).

9. The method according to claim 8, It is characterized in that The corrected battery health status calculated by the aging correction factor includes: Calculated by the following formula: SOH cor γ·SO₄ ref =f(β)SO H ref ; Among them, SOH cor is the corrected battery health status.

10. The method according to claim 1, It is characterized in that Also includes: Preset impedance spectrum parameter deviation alarm value b RC 、b RS and b CS , calculate the deviation value a of the impedance spectrum parameter RC 、a RS and a CS , the formula is as follows: a RC is the battery ohmic internal resistance deviation value; a Rs is the battery polarization internal resistance deviation value; a Cs is the battery polarization capacitance deviation value; According to the deviation value a RC 、a RS and a CS Set and deviation alarm value b RC 、b RS and b CS Compare and make alarm judgment.

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