CN106872905A - A kind of full battery parameter acquisition methods of monomer lithium ion - Google Patents

Abstract

The invention provides a method for acquiring parameters of a single lithium-ion full battery, which belongs to the field of new energy research. It includes the following steps: Step 1: Establish a mathematical model of electrochemical impedance spectroscopy of lithium-ion batteries; Step 2: Measure the electrochemical impedance spectroscopy of single lithium-ion full batteries to be tested; Step 3: According to the established mathematical model, the measured electrochemical impedance spectroscopy Impedance spectroscopy is used to identify parameters in frequency bands to obtain the parameters of the positive and negative electrodes of the single lithium-ion full battery to be tested. The present invention aims at the defect of poor parameter identification effect when the existing half-battery model is used for a full battery, and combines the characteristics of the electrochemical impedance spectrum of the lithium-ion battery, adopts a method of parameter identification in frequency bands, and can quickly and accurately obtain lithium-ion The positive and negative model parameters of the full battery. The invention is used for aging mechanism analysis, SOC estimation and life prediction of lithium ion battery.

Description

A method for acquiring parameters of a single lithium-ion full battery

technical field

The invention relates to a parameter acquisition method of a lithium ion battery, in particular to a parameter acquisition method of a single lithium ion full battery, belonging to the field of new energy research.

Background technique

Lithium-ion batteries have outstanding advantages such as high voltage, high energy density, good cycle performance and no memory effect, and have been widely used. In the research of lithium-ion batteries, Electrochemical Impedance Spectroscopy (EIS) technology is widely used. Electrochemical Impedance Spectroscopy is also called AC Impedance Spectroscopy. The interface reaction, charge transfer, diffusion and other processes are effectively decoupled, and its measurement and analysis techniques are widely used in the description of battery characteristics, which can then analyze the battery state and improve battery preparation. EIS technology also provides a basis for judging the battery's health status assessment, but it is currently mostly used for qualitative analysis of the speed of the internal process of the battery, the difficulty of the electrode reaction, etc., and is rarely used in battery management.

The mathematical model of electrochemical impedance spectroscopy for lithium-ion batteries is based on the theory of porous electrodes and concentrated solutions. It mathematically describes the electrochemical reaction and the charge transfer in condensates composed of single particles, and extends the condensate model to porous electrodes. The structure of the electrode/electrolyte interface of the main active material particles is described, and analytical formulas for the electrochemical reactions and charge transfer in condensates are established with high precision. However, this model is a half-cell model, which is mostly used in the research of half-cells and three-electrode lithium-ion batteries (with reference electrodes), while the current commercial lithium-ion batteries are mostly two-electrode full batteries (abbreviated as full batteries). If the model is used in a lithium-ion full battery, it is necessary to superimpose two models of the positive electrode and the negative electrode to obtain the full battery model. At this time, the model parameters are too many and coupled with each other, the identification time is long and the accuracy is very low, so the model is difficult to apply into a two-electrode Li-ion battery.

Contents of the invention

The invention provides a method for acquiring parameters of a single lithium-ion full battery that combines the electrochemical impedance spectrum mathematical model of the half-cell with parameter identification and improves the accuracy of parameter identification.

A method for acquiring parameters of a single lithium ion full battery of the present invention, said method comprising the steps of:

Step 1: Establish a mathematical model of lithium-ion battery electrochemical impedance spectroscopy;

Step 2: Measure the electrochemical impedance spectroscopy of the single lithium-ion full battery to be tested;

Step 3: According to the established mathematical model, the parameters of the measured electrochemical impedance spectrum are identified in frequency bands, and the parameters of the positive and negative electrodes of the single lithium-ion full battery to be tested are obtained.

Preferably, said step three includes:

In the high-frequency band of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the negative electrode parameters of the single lithium-ion full battery to be tested;

In the middle and low frequency bands of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the positive electrode parameters of the single lithium-ion full battery to be tested.

Preferably, the lithium-ion battery electrochemical impedance spectroscopy mathematical model established includes:

The single particle impedance of the SEI film is not considered:

Among them, the load transfer resistance R _ct =RT/(i ₀ F), R represents the gas constant, T represents the temperature, i ₀ represents the exchange current density, F represents the Faraday constant, κ is 1, j represents an imaginary number, ω represents the frequency, Indicates the partial conduction of the potential to the concentration, and C _dl indicates the electric double layer capacitance;

Transfer Function: R _pp represents the particle radius, D _s represents the solid phase diffusion coefficient;

Consider the single particle impedance of the SEI film:

Among them, R ₀ represents the ohmic internal resistance, Z _sei represents the impedance of the SEI film, and C _sei represents the capacitance of the SEI film;

Impedance of SEI mode:

Among them, the intermediate variable D _sei represents the diffusion coefficient in the SEI film, δ′ _sei = δ _sei -δ _dl , δ _sei represents the thickness of the SEI film, δ _dl represents the thickness of the electrical double layer, σ _sei represents the conductivity of the SEI film, R ₂ =R _pp +δ _dl , R ₃ =R ₂ +δ′ _sei ;

Condensate resistance:

Among them, the import function Intermediate variable D _{△, e} = D _{+, e} -D _{-, e} , D _{+, e} represent the liquid phase diffusion coefficient of the positive electrode, D _{-, e} represent the liquid phase diffusion coefficient of the negative electrode, τ _sp represents the tortuous factor in the condensate, Indicates the electrolyte volume fraction in the condensate, σ _e represents the liquid phase conductivity, R _sp represents the radius of the condensate, and c _ref represents the lithium ion reference concentration;

Porous electrode impedance:

Among them, the intermediate variable L represents the electrode thickness, Indicates the electrolyte volume fraction, the tortuosity factor in the τ _pe electrode, Disturbance component liquid phase diffusion coefficient, D _e liquid phase diffusion coefficient,

Table 1 Some related parameters of condensate impedance and porous electrode impedance

Intermediate variable ζ=D _△,e /D _e , intermediate variable Z _pp take or Intermediate variables t ₊ represents the lithium ion transfer number.

Preferably, the second step adopts a potentiostatic in-situ electrochemical impedance spectroscopy test method to measure the electrochemical impedance spectroscopy of the single lithium-ion full battery to be tested.

Preferably, in the second step: the amplitude of the sinusoidal voltage during the test is selected as 5mV to 10mV, the upper limit of the high frequency of the test frequency is 1000Hz, the lower limit of the low frequency of the test frequency is 0.01Hz, and the single lithium ion to be tested is fully The room temperature of the battery is 25°C.

The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

The beneficial effect of the present invention is that the present invention aims at the defect that the existing lithium-ion battery electrochemical impedance spectrum mathematical model is used for a full battery, and the parameter identification effect is poor. Combining with the characteristics of the lithium-ion battery electrochemical impedance spectrum, a The frequency band parameter identification method can quickly and accurately obtain the positive and negative electrode model parameters of lithium-ion full batteries, and realize the direct application of this model in the research of commercial lithium-ion batteries, in order to use this model to analyze the aging mechanism of lithium-ion batteries , SOC estimation, life prediction, etc. have laid the foundation.

Description of drawings

Fig. 1 is a schematic flow chart of the present invention.

Figure 2 is a schematic flow chart of the genetic algorithm.

FIG. 3 is an electrochemical impedance spectrum of a single lithium-ion full battery measured.

Fig. 4 is a measured electrochemical impedance spectrum and a simulated electrochemical impedance spectrum using the method of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

This embodiment is described in conjunction with FIG. 1. A method for acquiring parameters of a single lithium-ion full battery in this embodiment includes the following steps:

Step 1: Establish a mathematical model of lithium-ion battery electrochemical impedance spectroscopy;

Step 2: Measure the electrochemical impedance spectroscopy of the single lithium-ion full battery to be tested;

Step 3: According to the established mathematical model, the parameters of the measured electrochemical impedance spectrum are identified in frequency bands, and the parameters of the positive and negative electrodes of the single lithium-ion full battery to be tested are obtained.

The mathematical model of the electrochemical impedance spectrum of the lithium-ion battery established in the first step of this embodiment is a half-cell model, and the electrochemical impedance spectrum of the full battery is measured in the second step. The model parameters of the positive and negative electrodes of the battery, that is, the parameters of the single lithium-ion full battery to be tested are obtained.

In a preferred embodiment, step three includes:

In the high-frequency band of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the negative electrode parameters of the single lithium-ion full battery to be tested;

In the middle and low frequency bands of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the positive electrode parameters of the single lithium-ion full battery to be tested.

The genetic algorithm in this embodiment is a global optimization adaptive probability search algorithm developed by referring to the natural selection and genetic evolution mechanism of organisms, and the genetic algorithm will be described below.

Suppose the problem to be optimized is:

Among them, X is the parameter set to be identified, which adopts real-valued coding and contains N _d parameters to be identified; S is the search space, which is:

Lower and Upper are the lower and upper bounds of the search space for each parameter to be identified, respectively. The flow chart of the algorithm is shown in Figure 2.

In an embodiment, the objective function determined by the genetic algorithm is set as:

Among them, N is the number of frequency points in the electrochemical impedance spectroscopy test, with are the real and imaginary parts of the measured electrochemical impedance spectrum, respectively, with are the real and imaginary parts of the simulated electrochemical impedance spectrum, respectively. α is the weight to adjust the proportion of the imaginary part in the objective function. Since the imaginary part of the lithium-ion battery impedance is more sensitive to low frequencies, the weights used by the objective function are different at high, medium, and low frequencies. The lower the frequency, the greater the weight.

In the electrochemical impedance spectroscopy of lithium-ion batteries, the battery impedance in the high frequency band is dominated by the negative electrode, and in the low frequency band it is mainly contributed by the positive electrode. The reason why the battery impedance in the high-frequency band is dominated by the negative electrode is that the high-frequency region is a semicircle related to the passage of lithium ions through the SEI film, and the SEI film of the negative electrode plays a major role; in addition, the SEI film is very stable and can be used normally in lithium-ion batteries and batteries. During the entire charge and discharge cycle life of the battery, there will not be a large change, so the impedance of the negative electrode of the battery remains almost unchanged. The impedance of the full battery is mainly contributed by the positive electrode, and the impedance of the negative electrode is small and stable. The impedance of the battery increases during use is also caused by the impedance of the positive electrode. Therefore, in the middle and low frequency bands, the impedance of the full battery can be replaced by the positive electrode impedance.

To sum up, this embodiment adopts the method of frequency division identification to realize the application of the half-cell model in the commercial full battery, realize the decoupling of the positive and negative parameters of the battery, and obtain more accurate positive and negative parameters respectively. .

The high frequency band in this embodiment refers to a frequency band with a frequency greater than 30 Hz, and the middle and low frequency bands refer to a frequency band with a frequency less than 20 Hz.

In a preferred embodiment, the established lithium-ion battery electrochemical impedance spectroscopy mathematical model includes:

In the impedance modeling of a single particle, the impedance response of the system under the excitation of a small sinusoidal signal of frequency ω is solved to establish the impedance response, and the obtained single particle impedance is shown in formulas (4) and (5).

The single particle impedance of the SEI film is not considered:

Among them, the load transfer resistance R _ct =RT/(i ₀ F), R represents the gas constant, T represents the temperature, i ₀ represents the exchange current density, F represents the Faraday constant, κ is 1, j represents an imaginary number, ω represents the frequency, Indicates the partial conduction of the potential to the concentration, and C _dl indicates the electric double layer capacitance;

Transfer Function:

R _pp represents the particle radius, D _s represents the solid phase diffusion coefficient;

Consider the single particle impedance of the SEI film:

Among them, R ₀ represents the ohmic internal resistance, Z _sei represents the impedance of the SEI film, and C _sei represents the capacitance of the SEI film;

Impedance of SEI mode:

Among them, the intermediate variable D _sei represents the diffusion coefficient in the SEI film, δ′ _sei = δ _sei -δ _dl , δ _sei represents the thickness of the SEI film, δ _dl represents the thickness of the electrical double layer, σ _sei represents the conductivity of the SEI film, R ₂ =R _pp +δ _dl , R ₃ =R ₂ +δ′ _sei ;

In the modeling of condensate impedance, the microscopic equations are averaged by representative volume units, such as the volume average method to average the liquid phase control equation, etc., to obtain the condensate impedance:

Among them, the import function Intermediate variable D _{△, e} = D _{+, e} -D _{-, e} , D _{+, e} represent the liquid phase diffusion coefficient of the positive electrode, D _{-, e} represent the liquid phase diffusion coefficient of the negative electrode, τ _sp represents the tortuous factor in the condensate, Indicates the electrolyte volume fraction in the condensate, σ _e represents the liquid phase conductivity, R _sp represents the radius of the condensate, and c _ref represents the lithium ion reference concentration;

According to the porous electrode theory and concentrated solution theory, the condensate impedance model is extended to the porous electrode impedance modeling. The porous electrode impedance:

Among them, the intermediate variable L represents the electrode thickness, Indicates the electrolyte volume fraction, the tortuosity factor in the τ _pe electrode, Disturbance component liquid phase diffusion coefficient, D _e liquid phase diffusion coefficient,

Table 1 Some related parameters of condensate impedance and porous electrode impedance

Intermediate variable ζ=D _△,e /D _e , intermediate variable Z _pp represents the individual particle impedance, the intermediate variable t ₊ represents the lithium ion transfer number. The model has a total of 26 parameters, of which 6 parameters have known values and 19 parameters need to be identified. The known parameters mainly include physical constants and some parameters obtained from relevant literature and battery manuals, as shown in Table 2. The parameters to be identified include unknown parameters and parameters that change during battery aging, as shown in Table 3.

Table 2 Known parameters of lithium-ion battery impedance model

symbol physical meaning unit Remark reference concentration Depends on the battery model L Electrode thickness m Depends on the battery model Lithium ion transfer number - Depends on the battery model R gas constant 8.3143 f Faraday constant 96485 T temperature K 295.15

Table 3 Parameters to be identified in the lithium-ion battery impedance model

There are usually two test methods for electrochemical impedance spectroscopy: constant current test and constant potential test. Constant current test means that the excitation of the battery is a composite current value obtained by superimposing a direct current (can be 0) with a sinusoidal current, and at the same time measure the AC voltage response of the system, and the impedance can be obtained according to the ratio of voltage and current; constant potential test It means that the excitation of the battery is a composite voltage value obtained by superimposing a constant voltage and a sinusoidal voltage determined by a certain value. At the same time, the AC current response of the system is measured, and the impedance can be obtained according to the ratio of voltage and current.

In the test of lithium-ion batteries, if the constant current method is used for measurement, the battery will be in the case of charging and discharging, resulting in inaccurate impedance testing, so step 2 of this embodiment adopts constant potential in-situ electrochemical impedance spectroscopy The test method is to measure the electrochemical impedance spectrum of the single lithium-ion full battery to be tested. In the in-situ electrochemical impedance spectroscopy test method, the constant potential is set to the open circuit voltage of the battery, which can ensure that the test is carried out in a stable state inside the battery. This method is called constant potential in-situ EIS test.

During the electrochemical impedance spectroscopy test, the amplitude of the sinusoidal voltage to be tested should not be too high, otherwise it will easily affect the linear characteristics of the battery system, and the amplitude of the sinusoidal voltage to be tested is too low to effectively stimulate the battery system. It is 5mV～10mV; the measurement frequency range considers the application frequency range of the model and the practical significance of electrochemical impedance spectroscopy. Generally, the high-frequency upper limit of the frequency is 1000Hz, considering the accuracy of the electrochemical workstation at low frequencies and the measurement time. The length, under the premise that electrochemical impedance spectroscopy can reflect the diffusion behavior of the battery, the lower limit of the low frequency used is 0.01Hz; in addition, the constant temperature time, the duration of maintaining the open circuit voltage, etc. have an important impact on the electrochemical impedance spectroscopy test of the battery .

The measuring equipment in this embodiment includes a CS impedance spectroscopy tester, a PC, a battery holder, a fixture, and the like. The battery to be tested is a Samsung ICR18650-22F lithium-ion battery with a capacity of 2200mhA. In the actual measurement, the sinusoidal voltage amplitude is selected as 10mV; the measurement frequency range is 0.01-1000Hz, and the room temperature is 25°C. The measured electrochemical impedance The spectrum is shown in Figure 3. The impedance spectrum is often represented by a Nyquist diagram. It should be noted that in electrochemistry, the Nyquist diagram is used to take -Z" as the vertical axis and Z' as the horizontal axis. The electrochemical performance of lithium-ion batteries The impedance spectrum usually consists of two capacitive semicircles at high and intermediate frequencies and a slanted line at low frequencies. Among them, the high frequency region is a semicircle related to the diffusion and migration of lithium ions through the SEI film; the intermediate frequency region is a semicircle related to the charge transfer process; The oblique line related to the solid-state diffusion of lithium ions in the low frequency region.

The positive and negative electrode parameters of the lithium-ion battery obtained by the method of step three are shown in Table 4, Table 5, and Table 6. The simulated electrochemical impedance spectrum and the actual electrochemical impedance spectrum obtained by using the identified parameters are shown in Fig. 4 .

Table 4 Known parameters of lithium-ion battery impedance model

symbol physical meaning unit value reference concentration 1000 Electrode thickness (positive electrode) m 2.4e-05 Electrode Thickness (Negative) m 1.67e-05 Lithium ion transfer number - 0.35 R gas constant 8.3143 f Faraday constant 96485 T temperature K 295.15

Table 5 Impedance model parameters of positive lithium-ion battery

Table 6 Negative Lithium-ion Battery Impedance Model Parameters

Although the invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It is therefore to be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the invention as defined by the appended claims. It shall be understood that different dependent claims and features described herein may be combined in a different way than that described in the original claims. It will also be appreciated that features described in connection with individual embodiments can be used in other described embodiments.

Claims (5)

1. A single lithium ion full battery parameter acquisition method is characterized in that, the method comprises the steps: Step 1: Establish a mathematical model of lithium-ion battery electrochemical impedance spectroscopy; Step 2: Measure the electrochemical impedance spectroscopy of the single lithium-ion full battery to be tested; Step 3: According to the established mathematical model, the parameters of the measured electrochemical impedance spectrum are identified in frequency bands, and the parameters of the positive and negative electrodes of the single lithium-ion full battery to be tested are obtained. 2. A method for acquiring parameters of a single lithium-ion full battery according to claim 1, wherein said step 3 comprises: In the high-frequency band of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the negative electrode parameters of the single lithium-ion full battery to be tested; In the middle and low frequency bands of the measured electrochemical impedance spectrum, the established impedance mathematical model is used to analyze the electrochemical impedance spectrum, and the genetic algorithm is used for parameter identification to obtain the positive electrode parameters of the single lithium-ion full battery to be tested. 3. a kind of monomer lithium ion full battery parameter acquisition method according to claim 2, is characterized in that, the lithium ion battery electrochemical impedance spectroscopy mathematical model of establishment comprises: The single particle impedance of the SEI film is not considered: ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; p</span>}}^{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j\&omega;C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; l</span>}}}$ Among them, the load transfer resistance R _ct =RT/(i ₀ F), R represents the gas constant, T represents the temperature, i ₀ represents the exchange current density, F represents the Faraday constant, κ is 1, j represents an imaginary number, ω represents the frequency, Indicates the partial conduction of the potential to the concentration, and C _dl indicates the electric double layer capacitance; Transfer Function: R _pp represents the particle radius, D _s represents the solid phase diffusion coefficient; Consider the single particle impedance of the SEI film: ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; p</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\frac{\mathrm{<span\; class="notranslate">\; \&kappa;</span>}}{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; p</span>}}^{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j\&omega;C</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}$ Among them, R ₀ represents the ohmic internal resistance, Z _sei represents the impedance of the SEI film, and C _sei represents the capacitance of the SEI film; Impedance of SEI mode: ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>}$ Among them, the intermediate variable D _sei represents the diffusion coefficient in the SEI film, δ′ _sei = δ _sei -δ _dl , δ _sei represents the thickness of the SEI film, δ _dl represents the thickness of the electrical double layer, σ _sei represents the conductivity of the SEI film, R ₂ =R _pp +δ _dl , R ₃ =R ₂ +δ′ _sei ; Condensate resistance: ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}}\frac{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; p</span>}}}{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; p</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\frac{{\mathrm{<span\; class="notranslate">\; RT\&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{{\mathrm{<span\; class="notranslate">\; FR</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; p</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; FD</span>}}_{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; e</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; f</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; p</span>}}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}$ Among them, the import function Intermediate variable D _{△, e} = D _{+, e} -D-, _e , D _{+, e} represent the liquid phase diffusion coefficient of the positive electrode, D-, _e represent the liquid phase diffusion coefficient of the negative electrode, τ _sp represents the tortuous factor in the condensate, Indicates the electrolyte volume fraction in the condensate, σ _e represents the liquid phase conductivity, R _sp represents the radius of the condensate, and c _ref represents the lithium ion reference concentration; Porous electrode impedance: ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; )</span>\sqrt{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\mathrm{<span\; class="notranslate">\; tanh</span>}<span\; class="notranslate">\; (</span>\sqrt{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&upsi;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; )</span>\sqrt{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}\mathrm{<span\; class="notranslate">\; tanh</span>}<span\; class="notranslate">\; (</span>\sqrt{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}<span\; class="notranslate">\; )</span>}\frac{{\mathrm{<span\; class="notranslate">\; L\&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; e</span>}}}{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; p</span>}\mathrm{<span\; class="notranslate">\; e</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}$ Among them, the intermediate variable L represents the electrode thickness, Indicates the electrolyte volume fraction, the tortuosity factor in the τ _pe electrode, Disturbance component liquid phase diffusion coefficient, D _e liquid phase diffusion coefficient, Table 1 Some related parameters of condensate impedance and porous electrode impedance Intermediate variable ζ=D _△,e /D _e , intermediate variable Z _pp take or Intermediate variables t ₊ represents the lithium ion transfer number. 4. A method for acquiring parameters of a single lithium ion full battery according to claim 2 or 3, wherein said step 2 uses a constant potential in-situ electrochemical impedance spectroscopy test method to measure the full Electrochemical impedance spectroscopy of the battery. 5. The method for obtaining parameters of a single lithium ion full battery according to claim 4, wherein in said step 2: the amplitude of the sinusoidal voltage during the test is selected as 5mV～10mV, and the high frequency of the test frequency is The limit is 1000Hz, the lower limit of the test frequency is 0.01Hz, and the room temperature of the single lithium-ion full battery to be tested is 25°C.