Battery direct current internal resistance decomposition method and device, electronic equipment and medium

Abstract

The invention provides a battery direct-current internal resistance decomposition method and device, electronic equipment and a medium, and the method comprises the steps: firstly obtaining an electrochemical impedance spectrum and a direct-current internal resistance spectrum of a battery; ohmic impedance, electronic impedance, charge transfer impedance and solid electrolyte interface impedance of the battery are obtained according to the electrochemical impedance spectrum and the direct-current internal resistance spectrum, and then direct-current internal resistance and open-circuit voltage virtual impedance of the battery are obtained according to the direct-current internal resistance spectrum; and finally, according to the known ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the direct-current internal resistance and the open-circuit voltage virtual impedance, the diffusion impedance of the battery is calculated and obtained, so that the decomposition of the direct-current internal resistance of the battery is quickly and efficiently completed completely based on the calculation decomposition of spectrogram data. The method can quantitatively identify the resistance values in the DC internal resistance of the battery, can identify the influence of the change of the component in the electrochemical system on the impedance of each part, and has important significance for guiding the development of the battery cell.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a method, device, electronic device and medium for decomposing the DC internal resistance of a battery. Background Art

[0002] The DC internal resistance is an important technical index for measuring the performance of a battery, and has an extremely important impact on the power performance and charge-discharge efficiency of the battery. Analyzing the variation law of the DC internal resistance is also an important means for battery failure analysis. The DC internal resistance of a battery includes: ohmic resistance, SEI impedance, charge transfer impedance, diffusion impedance, ohmic polarization impedance, electrochemical polarization impedance, concentration polarization impedance, etc. Obtaining the impedance information of each part inside the battery can effectively guide battery design, conduct cell failure analysis, and assist in the development of battery products.

[0003] However, in the prior art, there are few technical solutions for decomposing the DC internal resistance of a battery, and the very few disclosed DC internal resistance decomposition technical solutions are also based on the piecemeal disassembly testing and fitting calculation of the internal model structure of the battery, and the decomposition process is relatively cumbersome and the calculation amount is large.

[0004] Therefore, there is an urgent need for an efficient technical solution for decomposing the DC internal resistance of a battery at present. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the present invention provides a technical solution for decomposing the DC internal resistance of a battery to solve the above technical problems.

[0006] To achieve the above object and other related objects, the technical solution provided by the present invention is as follows.

[0007] A method for decomposing the DC internal resistance of a battery includes:

[0008] Obtaining the electrochemical impedance spectrum and the DC internal resistance spectrum of the battery;

[0009] Based on the same equivalent circuit of the DC internal resistance, obtaining the ohmic impedance, electronic impedance, charge transfer impedance and solid electrolyte interface impedance of the battery according to the electrochemical impedance spectrum and the DC internal resistance spectrum;

[0010] Obtaining the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum;

[0011] Obtaining the diffusion impedance of the battery according to the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance.

[0012] Optionally, for the same equivalent circuit based on the DC internal resistance, the steps of obtaining the ohmic impedance, electronic impedance, charge transfer impedance, and solid electrolyte interface impedance of the battery according to the electrochemical impedance spectrum and the DC internal resistance spectrum include:

[0013] Obtaining the ohmic impedance and relaxation time according to the electrochemical impedance spectrum;

[0014] Obtaining the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance, where the DC internal resistance analysis formula includes a first DC internal resistance analysis formula and a second DC internal resistance analysis formula, and substituting the ohmic impedance and the relaxation time into the first DC internal resistance analysis formula;

[0015] Fitting the DC internal resistance spectrum with the first DC internal resistance analysis formula with known partial parameters to obtain the ohmic impedance, the electronic impedance, the charge transfer impedance, and the solid electrolyte interface impedance.

[0016] Optionally, the step of obtaining the relaxation time according to the electrochemical impedance spectrum includes:

[0017] Performing relaxation time distribution analysis on the electrochemical impedance spectrum to obtain a relaxation time distribution spectrogram;

[0018] Obtaining a plurality of the relaxation times according to the relaxation time distribution spectrogram.

[0019] Optionally, the step of obtaining the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance includes:

[0020] Analyzing in combination with the equivalent circuit of the DC internal resistance and the relaxation time distribution spectrogram to obtain the first DC internal resistance analysis formula;

[0021] Analyzing in combination with the equivalent circuit of the DC internal resistance and the DC internal resistance spectrum to obtain the second DC internal resistance analysis formula.

[0022] Optionally, the equivalent circuit of the DC internal resistance includes a resistor and a plurality of resistor-capacitor parallel structures, and the resistor is connected in series with the plurality of resistor-capacitor parallel structures in sequence.

[0023] Optionally, the first DC internal resistance analysis formula is:

[0024]

[0025] where DCR(t) represents the DC internal resistance, R Ω represents the ohmic impedance, R k represents the electronic impedance, the charge transfer impedance, or the solid electrolyte interface impedance, t represents time, and τ kRepresents the relaxation time, R d Represents the diffusion impedance, R ocv Represents the open-circuit voltage virtual impedance, and k takes integer values from 1 to n.

[0026] Optionally, the second analytical formula for the DC internal resistance is:

[0027] DCR = R Ω +R e +R sei +R ct +R d +R ocv

[0028] Wherein, DCR represents the DC internal resistance, R Ω Represents the ohmic impedance, R e Represents the electronic impedance, R sei Represents the solid electrolyte interface impedance, R ct Represents the charge transfer impedance, R d Represents the diffusion impedance, R ocv Represents the open-circuit voltage virtual impedance.

[0029] Optionally, the steps of obtaining the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum include:

[0030] Obtain the DC internal resistance according to the DC internal resistance spectrum;

[0031] Obtain the open-circuit voltage virtual impedance according to the DC internal resistance spectrum.

[0032] Optionally, the calculation formula for the open-circuit voltage virtual impedance is:

[0033]

[0034] Wherein, R ocv Represents the open-circuit voltage virtual impedance, U1 represents the battery voltage before charge and discharge, U3 represents the open-circuit voltage after the battery is discharged directly and left standing for a preset time, and I represents the charge and discharge current.

[0035] Optionally, the steps of obtaining the diffusion impedance of the battery according to the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance include:

[0036] Substitute the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance into the second analytical formula for the DC internal resistance to calculate the diffusion impedance of the battery.

[0037] A device for decomposing the DC internal resistance of a battery, the device comprising:

[0038] A data acquisition module for acquiring the electrochemical impedance spectrum and the DC internal resistance spectrum of the battery;

[0039] A first processing module for obtaining the ohmic impedance, electron impedance, charge transfer impedance and solid electrolyte interface impedance of the battery based on the same equivalent circuit of the DC internal resistance according to the electrochemical impedance spectrum and the DC internal resistance spectrum;

[0040] A second processing module for obtaining the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum;

[0041] A third processing module for obtaining the diffusion impedance of the battery according to the ohmic impedance, the electron impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance.

[0042] An electronic device, comprising:

[0043] One or more processors;

[0044] A storage device for storing one or more programs, which when executed by the one or more processors, cause the electronic device to implement the method for decomposing the DC internal resistance of a battery as described in any one of the above.

[0045] A computer-readable storage medium having stored thereon computer-readable instructions which, when executed by a processor of a computer, cause the computer to execute the method for decomposing the DC internal resistance of a battery as described in any one of the above.

[0046] Advantages of the present invention: In the present invention, first, the electrochemical impedance spectrum and the DC internal resistance spectrum of the battery are obtained, and then, based on the same equivalent circuit of the DC internal resistance, the ohmic impedance, electron impedance, charge transfer impedance and solid electrolyte interface impedance of the battery can be obtained according to the electrochemical impedance spectrum and the DC internal resistance spectrum. Then, the DC internal resistance and the open-circuit voltage virtual impedance of the battery are obtained according to the DC internal resistance spectrum. Finally, the diffusion impedance of the battery is calculated and obtained according to the known ohmic impedance, electron impedance, charge transfer impedance, solid electrolyte interface impedance, DC internal resistance and open-circuit voltage virtual impedance. In this way, based entirely on the calculation and decomposition of spectral data, the decomposition of the DC internal resistance of the battery is completed quickly and efficiently, the magnitudes of the respective resistance values in the DC internal resistance of the battery can be quantitatively identified, and the influence of the change of components in the electrochemical system on each part of the impedance can be identified. For example, the influence of the change in the amount of electrolyte additive / the change in the binder / the change in the conductive carbon on the charge transfer impedance, and the influence of the change in the electrode material on the diffusion impedance, etc., which is of great significance for guiding the development of battery cells.

[0047] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0049] Figure 1 is a schematic diagram of the steps of a method for decomposing the DC internal resistance of a battery shown in an exemplary embodiment of the present application;

[0050] Figure 2 is the electrochemical impedance spectrum of a battery shown in an exemplary embodiment of the present application;

[0051] Figure 3 is the DC internal resistance spectrum of a battery shown in an exemplary embodiment of the present application;

[0052] Figure 4 is the equivalent circuit of the DC internal resistance of a battery shown in an exemplary embodiment of the present application;

[0053] Figure 5 is a comparison schematic diagram of the analysis data obtained by the specific relaxation time distribution analysis and the fitting of the DC internal resistance spectrum respectively shown in an exemplary embodiment of the present application;

[0054] Figure 6 is shown in an exemplary embodiment of the present application as Figure 2 the relaxation time distribution spectrogram obtained by performing relaxation time distribution analysis on the electrochemical impedance spectrum;

[0055] Figure 7 is shown in an exemplary embodiment of the present application as the fitting schematic diagram on the Figure 3 DC internal resistance spectrum;

[0056] Figure 8 is a schematic diagram of the DC internal resistance and the open-circuit voltage virtual impedance of a battery shown in an exemplary embodiment of the present application;

[0057] Figure 9 is a schematic diagram of the structure of a device for decomposing the DC internal resistance of a battery shown in an exemplary embodiment of the present application;

[0058] Figure 10 is a schematic diagram of the structure of a computer system corresponding to an electronic device shown in an exemplary embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0060] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0061] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0062] As mentioned in the background technology, the inventors have found that obtaining the impedance information of each part of the battery DC internal resistance can effectively guide battery design, conduct battery cell failure analysis, and assist in battery product development. However, there are few technical solutions for decomposing the battery DC internal resistance in the prior art. Even the few DC internal resistance decomposition technical solutions that have been disclosed are based on the one-by-one split testing and fitting calculation of the battery internal model structure. The decomposition process is relatively cumbersome and requires a large amount of calculation.

[0063] In detail, the prior art 1 (CN114280480A) discloses a method for decomposing the DC internal resistance of a lithium-ion battery based on a numerical model, which comprises the steps of: classifying, combining and coupling the control equations and boundary conditions involved in the numerical model of the lithium-ion battery according to the conservation of mass, conservation of charge and conservation of energy; determining the electrochemical parameters associated with the decomposition of the battery internal resistance in the corresponding control equations of the lithium-ion battery to be decomposed, and obtaining an integrated solution corresponding to the electrochemical parameters; dividing the lithium-ion battery to be decomposed into an infinite number of units according to the integrated solution, averaging the internal resistance generated on each battery unit according to Ohm's law, determining the source of the internal resistance according to the battery structure and deforming the average internal resistance within the structural range, and then integrating to obtain the internal resistance of different components.

[0064] More specifically, in the prior art I, the numerical model of the lithium-ion battery involves the coupling of any one or several models among the single-particle model, pseudo-two-dimensional model, and three-dimensional model, including the electrochemical model, thermal model, or force model. Mass conservation involves the diffusion process of lithium ions in the cathode material particles, the diffusion process of lithium ions in the anode material particles, and the diffusion process of lithium ions in the electrolyte phase. Charge conservation involves the electron current passing through the positive electrode current collector, positive electrode material, negative electrode current collector, and negative electrode material, as well as the ion current in the positive electrode electrolyte, separator electrolyte, and negative electrode electrolyte. Energy conservation includes the heat capacity term, heat conduction term, and heat source term. The coupling is any combination of one or more of the electrochemical field, thermal field, or force field;

[0065] The cathode material of the lithium-ion battery to be disassembled involves one or several of lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate, mixed in any proportion. The anode material of the lithium-ion battery to be disassembled involves one or several of graphite, lithium titanate, silicon-based material, phosphorus-based material, tin-based material, germanium-based material, or zinc-based material, mixed in any proportion. The separator material of the lithium-ion battery to be disassembled involves any one or several of porous polymer membranes, non-woven fabric separators, and inorganic composite membranes. The electrolyte of the lithium-ion battery to be disassembled involves any one or several of inorganic liquid electrolytes, organic liquid electrolytes, inorganic solid electrolytes, organic liquid electrolytes, and molten salt electrolytes;

[0066] Electrochemical parameters involve any one parameter or a combination of several parameters, such as the available capacity of the battery, the initial lithium intercalation amount of the positive and negative electrode materials, the maximum lithium intercalation amount of the positive and negative electrode materials, the lithium ion diffusion coefficient of the positive and negative electrode materials, the equilibrium potential curve of the positive and negative electrode materials, the entropy heat coefficient curve of the positive and negative electrode materials, the thickness of the positive and negative electrodes and the separator, the volume fraction of the active material of the positive and negative electrodes, the liquid phase volume fraction of the positive and negative electrodes and the separator, the particle size of the positive and negative electrode materials, the tortuosity coefficient of the separator, the reaction rate constant of the positive and negative electrode materials, the solid-phase conductivity of the positive and negative electrode materials, the conductivity of the electrolyte, the lithium ion transference number of the separator, the cathode transfer coefficient of the positive and negative electrode materials, or the anode transfer coefficient of the positive and negative electrode materials.

[0067] It can be seen that the prior art I is mainly based on the piecemeal disassembly test and calculation of the internal model structure materials of the battery. The disassembly is relatively trivial, involving many parameters, and the corresponding calculation amount is also very large. Each impedance component needs to be measured first and then the result can be calculated. The decomposition process is relatively cumbersome and the calculation amount is large.

[0068] Specifically, the prior art two (CN116577682A) discloses a method for decomposing and testing the DC internal resistance of a secondary battery, which includes: obtaining the ohmic resistance R1 of the positive electrode structural member and the ohmic resistance R2 of the negative electrode structural member; calculating the positive current collector resistance R3 and the negative current collector resistance R4; calculating the positive electrode film resistance R5 and the negative electrode film resistance R6; obtaining the negative charge transfer resistance R7, the positive charge transfer resistance R8, the positive ion diffusion impedance R10, the negative ion diffusion impedance R11, and the negative SEI film impedance R12; obtaining the separator ion impedance R9 of the electrolyte in the separator; and converting the positive current collector resistance R3, the negative current collector resistance R4, the positive electrode film resistance R5, the negative electrode film resistance R6, the negative charge transfer resistance R7, the positive charge transfer resistance R8, the separator ion impedance R9, the positive ion diffusion impedance R10, the negative ion diffusion impedance R11, and the negative SEI film impedance R12 into the corresponding resistances of the secondary battery respectively.

[0069] More specifically, in the prior art two, the ohmic resistance R1 of the positive electrode structural member and the ohmic resistance R2 of the negative electrode structural member are directly measured by a resistance meter respectively. The positive current collector resistance R3 and the negative current collector resistance R4 are calculated according to the sizes of the positive current collector and the negative current collector respectively, involving the measurement of various sizes such as the resistivity of the current collector, the width of the tab, the length of the tab, and the thickness of the current collector. Measuring the positive electrode sheet resistance and the negative electrode sheet resistance, and calculating the positive electrode film resistance R5 and the negative electrode film resistance R6 respectively according to the positive electrode sheet resistance, the negative electrode sheet resistance, the positive current collector resistance R3, and the negative current collector resistance R4. Subsequent other resistances are also based on the test results of the instrument or complex calculations based on the test results and known results.

[0070] It can be seen that the prior art two is mainly based on the piecemeal disassembly test and calculation of the internal model structure materials of the battery. The disassembly is relatively trivial, involving many parameters, and the corresponding calculation amount is also very large. Each impedance component can only be obtained through either instrument testing or complex calculations based on measurement results or known parameters. The decomposition process is relatively cumbersome and the calculation amount is large.

[0071] From the above analysis, it can be known that most of the few DC internal resistance decomposition technical solutions in the prior art are based on the piecemeal disassembly test and fitting calculation of the internal model structure of the battery. The decomposition process is relatively cumbersome and the calculation amount is large.

[0072] To solve these problems, the present application respectively proposes a method for decomposing the DC internal resistance of a battery, a device for decomposing the DC internal resistance of a battery, an electronic device, a computer-readable storage medium, and a computer program product. The following will describe these embodiments in detail.

[0073] First, in the present application, as Figure 1As shown, a method for decomposing the DC internal resistance of a battery is proposed, which includes the steps:

[0074] S101. Obtain the electrochemical impedance spectrum and DC internal resistance spectrum of the battery;

[0075] Specifically, in step S101, through testing (such as testing with an electrochemical workstation), the electrochemical impedance spectrum (i.e., EIS spectrum, Electrochemical Impedance Spectroscopy) and DC internal resistance spectrum (i.e., DCR spectrum, Directive Current Resistance) of the battery (or electrochemical system) are obtained.

[0076] In an alternative embodiment of the present invention, for the same battery, its electrochemical impedance spectrum is obtained as Figure 2 shown, and its DC internal resistance spectrum is obtained as Figure 3 shown.

[0077] S102. Based on the same equivalent circuit of the DC internal resistance, obtain the ohmic impedance R Ω , electronic impedance R e , charge transfer impedance R ct and solid electrolyte interface impedance R sei of the battery according to the electrochemical impedance spectrum and DC internal resistance spectrum;

[0078] Specifically, in step S102, for the test data of the electrochemical impedance spectrum and DC internal resistance spectrum of the same battery (or electrochemical system), the same DC internal resistance equivalent circuit is used for analysis, and the obtained resistance values should be consistent.

[0079] Based on this, when analyzing the electrochemical impedance spectrum and DC internal resistance spectrum using the same DC internal resistance equivalent circuit, there are different impedance analysis formulas. Through horizontal comparison and fitting calculation of the two spectra, the ohmic impedance R Ω , electronic impedance R e , charge transfer impedance R ct and solid electrolyte interface impedance R sei of the battery (or electrochemical system) can be obtained.

[0080] For example, in an alternative embodiment of the present invention, the equivalent circuit of the DC internal resistance of the battery (or electrochemical system) is as Figure 4 shown, which includes a resistor (corresponding to the ohmic impedance R Ω ) and a plurality of resistor-capacitor parallel structures. The resistor and the plurality of resistor-capacitor parallel structures are connected in series in sequence. The first resistor-capacitor parallel structure includes a parallel connection of the electronic impedance R e and the first capacitor C 1, the second resistor-capacitor parallel structure includes a parallel solid electrolyte interface impedance R sei and the second capacitor C 2 , the third resistor-capacitor parallel structure includes a parallel charge transfer impedance R ct and the third capacitor C3. The equivalent circuit also includes two resistors in series (corresponding to the diffusion impedance R of the battery d and the open-circuit voltage virtual impedance R of the battery ocv ).

[0081] In an alternative embodiment of the present invention, for the same battery, based on the DC internal resistance equivalent circuit as shown in Figure 4 , the relaxation time distribution analysis (i.e., DRT analysis, Distribution of Relaxation Time) is performed on the electrochemical impedance spectrum as shown in Figure 2 , and the DC internal resistance spectrum as shown in Figure 3 is fitted (i.e., DCR fitting, Directive Current Resistance), and the data shown in Table 1 and the fitting curve as shown in Figure 5 are obtained.

[0082] Relaxation time number Relaxation time value / s Attributed impedance DRT analysis value / mΩ DCR fitting value / mΩ <![CDATA[τ 1 > 0.0003 <![CDATA[R e > 13.2 12.1 <![CDATA[τ 2 > 0.0015 <![CDATA[R sei > 14.7 16.4 <![CDATA[τ 3 > 0.0065 <![CDATA[R ct > 3.9 4.1 <![CDATA[τ 4 > 0.0601 <![CDATA[R ct > 1.2 2.9

[0083] Table 1

[0084] According to Table 1 and Figure 5 , it can be seen that by comparing the analysis data obtained by the two different test methods of relaxation time distribution analysis and DC internal resistance spectrum fitting, the results of the two are highly consistent. Within the allowable error range, the resistance values obtained by the two analysis methods are consistent, indicating that this method is highly feasible.

[0085] More specifically, based on the same equivalent circuit of the DC internal resistance, the steps S102 for obtaining the ohmic impedance, electron impedance, charge transfer impedance, and solid electrolyte interface impedance of the battery according to the electrochemical impedance spectrum and the DC internal resistance spectrum include:

[0086] S1021. Obtain the ohmic impedance R Ω and the relaxation time τ k from the electrochemical impedance spectrum;

[0087] S1022. Obtain the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance. The DC internal resistance analysis formula includes a first DC internal resistance analysis formula and a second DC internal resistance analysis formula, and substitute the ohmic impedance and the relaxation time into the first DC internal resistance analysis formula;

[0088] S1023. Fit the DC internal resistance spectrum with the first analytical formula of the DC internal resistance with known partial parameters to obtain the ohmic impedance, electronic impedance, charge transfer impedance, and solid electrolyte interface impedance.

[0089] Further, in step S1021, directly read the ohmic impedance R from the electrochemical impedance spectrum Ω (the intersection point of the impedance data measured at high frequency and the X-axis is the ohmic resistance R Ω ). For example, in an alternative embodiment of the present invention, the ohmic impedance R of the battery is read from the electrochemical impedance spectrum as shown in Figure 2 . Ω = 19.03 mΩ.

[0090] Further, in step S1021, obtain the relaxation time τ according to the electrochemical impedance spectrum k , including:

[0091] S10211. Perform relaxation time distribution analysis on the electrochemical impedance spectrum to obtain a relaxation time distribution spectrogram;

[0092] S10212. Obtain multiple relaxation times according to the relaxation time distribution spectrogram.

[0093] Specifically, in step S10211, perform relaxation time distribution analysis on the electrochemical impedance spectrum to obtain the corresponding relaxation time distribution spectrogram. The time point corresponding to the peak in the relaxation time distribution spectrogram is the relaxation time τ k . For example, in an alternative embodiment of the present invention, perform relaxation time distribution analysis on the electrochemical impedance spectrum as shown in Figure 2 to obtain the corresponding relaxation time distribution spectrogram as shown in Figure 6 .

[0094] Specifically, in step S10212, directly read multiple relaxation times τ 1 , τ 2 , …… and τ n from the relaxation time distribution spectrogram. The value of n is an integer of 3 or more, and determine the fitting interval and corresponding attributed impedance of each relaxation time. Among them, the first two relaxation times belong to the electronic impedance R e and the solid electrolyte interface impedance R sei respectively, and the subsequent other relaxation times all belong to the charge transfer impedance R ct . That is to say, the charge transfer impedance R ct may have more than one, and may have two or even more, but the relaxation times of multiple charge transfer impedances R ct are very close and coupled together.

[0095] For example, in an alternative embodiment of the present invention, according to Figure 6The data shown in the relaxation time distribution spectrogram are obtained as shown in Table 2. Among them, Figure 6 the last peak shown is a pseudo-peak.

[0096] Relaxation time number Relaxation time value / s Attributed impedance <![CDATA[τ 1 > 0.0003 <![CDATA[R e > <![CDATA[τ 2 > 0.0015 <![CDATA[R sei > <![CDATA[τ 3 > 0.0065 <![CDATA[R ct > <![CDATA[τ 4 > 0.0601 <![CDATA[R ct >

[0097] Table 2

[0098] As can be seen from the above table, the maximum relaxation time τ 4 is 0.0601 s, and the subsequent overall fitting time interval is taken as (0 - 0.1 s).

[0099] Furthermore, in step S1022, the DC internal resistance analysis formula includes a first DC internal resistance analysis formula and a second DC internal resistance analysis formula. The steps of obtaining the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance include:

[0100] S10221. Analyze by combining the equivalent circuit of the DC internal resistance and the relaxation time distribution spectrogram to obtain the first DC internal resistance analysis formula;

[0101] S10222. Analyze by combining the equivalent circuit of the DC internal resistance and the DC internal resistance spectrum to obtain the second DC internal resistance analysis formula.

[0102] For example, in an optional embodiment of the present invention, by combining the equivalent circuit of the DC internal resistance as shown in Figure 4 and the relaxation time distribution spectrogram as shown in Figure 6 for analysis, based on the equivalent fitting of the relaxation time distribution spectrogram, the first DC internal resistance analysis formula is obtained as follows:

[0103]

[0104] where DCR(t) represents the DC internal resistance, R Ω represents the ohmic impedance, R k represents the electronic impedance, charge transfer impedance or solid electrolyte interface impedance, t represents time, τ l represents the relaxation time, R d represents the diffusion impedance, and R ocv represents the open circuit voltage virtual impedance, τ k =R k C k , and the value of k is an integer from 1 to n.

[0105] By combining the equivalent circuit of the DC internal resistance as shown in Figure 4 and the DC internal resistance spectrum as shown in Figure 3 for analysis, based on the equivalent fitting of the DC internal resistance spectrum, the second DC internal resistance analysis formula is obtained as follows:

[0106] DCR = R Ω +Re +R sei +R ct +R d +R ocv (2);

[0107] Among them, DCR represents the direct current internal resistance, and R Ω represents the ohmic impedance, R e represents the electronic impedance, R sei represents the solid electrolyte interface impedance, R ct represents the charge transfer impedance, R d represents the diffusion impedance, R ocv represents the open circuit voltage virtual impedance.

[0108] It should be noted that for the test data of the electrochemical impedance spectrum and the direct current internal resistance spectrum of the same battery (or electrochemical system), the same direct current internal resistance equivalent circuit is used for analysis. Then, the resistance value of the direct current internal resistance obtained by analysis should be consistent, that is, DCR(t) = DCR.

[0109] Furthermore, in step S1022, the known ohmic impedance R Ω and each relaxation time τ 1 ~τ n are substituted into the first analysis formula of the direct current internal resistance.

[0110] Furthermore, in step S1023, the first analysis formula of the direct current internal resistance with known partial parameters is used to fit the direct current internal resistance spectrum. According to the fitting result, some coefficients of the first analysis formula of the direct current internal resistance with known partial parameters are deduced inversely, that is, the coefficients R 1 ~R n . Then, the ohmic impedance R Ω , the electronic impedance R e , the charge transfer impedance R ct and the solid electrolyte interface impedance R sei can be obtained. Among them, the coefficients R 1 ~R n correspond one-to-one to the electronic impedance R e , the solid electrolyte interface impedance R sei and the charge transfer impedance R ct .

[0111] For example, in an optional embodiment of the present invention, in combination with the ohmic impedance R of 19.03 mΩ Ω and the data shown in Table 2, the above data are substituted into the first analysis formula of the direct current internal resistance shown in formula (1) to obtain the first analysis formula of the direct current internal resistance with known partial parameters, and then the first analysis formula of the direct current internal resistance with known partial parameters is used to fit as Figure 3The DC internal resistance spectrum shown has a fitting time interval of (0 to 100 ms), and the time interval Δt between discrete fitting points is 1 ms. High-precision data fitting is performed to obtain the DC internal resistance spectrum as shown in Figure 7 and the data shown in Table 3 is obtained according to the fitting result.

[0112] <![CDATA[R k > Fitting value / mΩ <![CDATA[Relaxation time τ k / s]]> Attributed impedance <![CDATA[R Ω > 19.03 0.0000 <![CDATA[R Ω > <![CDATA[R 1 > 12.06 0.0003 <![CDATA[R e > <![CDATA[R 2 > 16.43 0.0015 <![CDATA[R sei > <![CDATA[R 3 > 4.05 0.0065 <![CDATA[R ct > <![CDATA[R 4 > 2.86 0.0601 <![CDATA[R ct >

[0113] Table 3

[0114] S103. Obtain the DC internal resistance DCR and the open-circuit voltage virtual impedance R of the battery according to the DC internal resistance spectrum ocv ;

[0115] Specifically, the steps of obtaining the DC internal resistance DCR and the open-circuit voltage virtual impedance R of the battery according to the DC internal resistance spectrum ocv S103 include:

[0116] S1031. Obtain the DC internal resistance DCR according to the DC internal resistance spectrum;

[0117] S1032. Obtain the open-circuit voltage virtual impedance R according to the DC internal resistance spectrum ocv .

[0118] Furthermore, in step S1031, the DC internal resistance DCR is directly obtained according to the DC internal resistance spectrum, that is, the DC internal resistance DCR is directly obtained based on the DC impedance test data. For example, in an alternative embodiment of the present invention, the DC internal resistance DCR at different times is directly obtained based on the DC internal resistance spectrum as shown in Figure 3 .

[0119] Furthermore, in step S1032, the open-circuit voltage virtual impedance R is directly obtained according to the DC internal resistance spectrum ocv , that is, the open-circuit voltage virtual impedance R is directly obtained based on the DC impedance test data ocv , as shown in Figure 8 , the calculation formula for the open-circuit voltage virtual impedance R ocv is:

[0120]

[0121] where R ocv represents the open-circuit voltage virtual impedance, U1 represents the battery voltage before charge and discharge, U3 represents the open-circuit voltage after the battery is discharged directly and left standing for a preset time (the standing time can be adjusted according to different systems, and generally a more accurate R value can be obtained when it is > 30 min), and I represents the charge and discharge current. ocv

[0122] More specifically, as shown in Figure 8 , the calculation formula for the DC internal resistance DCR is:

[0123]

[0124] Among them, DCR represents the DC internal resistance, U1 represents the battery voltage before charging and discharging, U2 represents the battery voltage after charging and discharging, and I represents the charging and discharging current.

[0125] It should be noted that when doing a DC internal resistance test, after the battery has been standing for a period of time, the battery open circuit voltage will change. When calculating the DC internal resistance, the virtual impedance calculated due to this voltage change is also included. This virtual resistance value calculated due to the battery voltage change after the battery is charged and discharged and has been standing for a period of time is defined as the open circuit voltage virtual impedance R ocv .

[0126] S104, according to the ohmic impedance R Ω 、Electronic impedance R e , Charge transfer impedance R ct , solid electrolyte interface impedance R sei , DC internal resistance DCR and open circuit voltage virtual impedance R ocv Get the diffusion impedance R of the battery d .

[0127] In detail, according to the ohmic impedance R Ω 、Electronic impedance R e , Charge transfer impedance R ct , solid electrolyte interface impedance R sei , DC internal resistance DCR and open circuit voltage virtual impedance R ocv Get the diffusion impedance R of the battery d Step S104 includes:

[0128] The ohmic resistance R Ω 、Electronic impedance R e , Charge transfer impedance R ct , solid electrolyte interface impedance R sei , DC internal resistance DCR and open circuit voltage virtual impedance R ocv Substitute into the second analytical formula of DC internal resistance and calculate the diffusion impedance R of the battery d .

[0129] As in an optional embodiment of the present invention, the unknown diffusion impedance R is calculated according to the second analytical formula of the DC internal resistance shown in formula (2): d .

[0130] Thus, based on the same DC internal resistance equivalent circuit, the present invention can obtain the ohmic impedance R of the battery according to the simultaneous coupling and fitting calculation between the electrochemical impedance spectrum and the DC internal resistance spectrum. Ω 、Electronic impedance Re , the charge transfer impedance R ct and the solid electrolyte interface impedance R sei . Then, according to the DC internal resistance spectrum, the DC internal resistance DCR and the open-circuit voltage virtual impedance R of the battery are obtained ocv . Finally, based on the known ohmic impedance R Ω , the electronic impedance R e , the charge transfer impedance R ct , the solid electrolyte interface impedance R sei , the DC internal resistance DCR and the open-circuit voltage virtual impedance R ocv , the diffusion impedance R of the battery is calculated and obtained d .

[0131] As described above, the present invention is completely based on the fitting calculation and decomposition of spectral data, quickly and efficiently completes the decomposition of the DC internal resistance of the battery, can quantitatively identify the magnitudes of the resistances in the DC internal resistance of the battery, and can identify the influence of the changes in the components in the electrochemical system on the impedance of each part, which has important significance for guiding the development of battery cells

[0132] It should be noted that the value measured for the DC internal resistance is the impedance exhibited by the battery during operation, including the ohmic impedance R Ω , the electronic impedance R e , the charge transfer impedance R ct , the solid electrolyte interface impedance R sei , the diffusion impedance R d , the ohmic polarization impedance, the electrochemical polarization impedance, and the concentration polarization impedance. However, the DC impedance test cannot distinguish them one by one, and the obtained DC internal resistance DCR is the coupling result of various physical and chemical processes. However, the influence of each part of the impedance on the battery performance is significantly different. For example, the solid electrolyte interface impedance R sei and the charge transfer impedance R ct are very greatly affected by temperature, especially the charge transfer impedance R ct , whose resistance value will increase significantly with the decrease of temperature. Therefore, they have a very crucial impact on the rate and low-temperature performance of the battery. By comparing the magnitudes of the solid electrolyte interface impedance R sei and the charge transfer impedance R ct , the quality of the low-temperature performance of the battery cell can be quickly identified; by designing the electrochemical system or electrolyte solution to reduce the solid electrolyte interface impedance R sei and the charge transfer impedance R ct , the low-temperature and rate performance of the battery cell can be significantly improved. Therefore, obtaining the solid electrolyte interface impedance R sei and the charge transfer impedance R ctThe quantitative information can effectively assist in the development of battery cells. Similarly, quantitatively identifying the resistance values of each part in the DC internal resistance (DCR) is of great significance for guiding the development of battery cells.

[0133] Secondly, based on the above battery DC internal resistance decomposition method, the present invention also provides a battery DC internal resistance decomposition device, as Figure 9 shown, the device includes:

[0134] A data acquisition module 91, configured to obtain the electrochemical impedance spectrum and DC internal resistance spectrum of the battery;

[0135] A first processing module 92, configured to obtain the ohmic impedance, electronic impedance, charge transfer impedance, and solid electrolyte interface impedance of the battery based on the same equivalent circuit of the DC internal resistance according to the electrochemical impedance spectrum and DC internal resistance spectrum;

[0136] A second processing module 93, configured to obtain the DC internal resistance and open circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum;

[0137] A third processing module 94, configured to obtain the diffusion impedance of the battery according to the ohmic impedance, electronic impedance, charge transfer impedance, solid electrolyte interface impedance, DC internal resistance, and open circuit voltage virtual impedance.

[0138] It should be noted that the battery DC internal resistance decomposition device provided here and the battery DC internal resistance decomposition method provided in the above embodiments belong to the same concept. The battery DC internal resistance decomposition device is used to implement the above battery DC internal resistance decomposition method, and the specific ways in which each module and unit perform operations have been described in detail in the method embodiments and will not be elaborated here. In actual applications, the battery DC internal resistance decomposition device can, as needed, allocate the above functions to different functional modules, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here either.

[0139] Meanwhile, the present application also provides an electronic device, which includes: one or more processors; a storage device for storing one or more programs, and when the one or more programs are executed by the one or more processors, the electronic device realizes the battery DC internal resistance decomposition method provided in each of the above embodiments.

[0140] Figure 10 shows a schematic structural diagram of a computer system of an electronic device suitable for implementing the embodiments of the present application. It should be noted that Figure 10 the computer system 100 of the electronic device shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of the present application.

[0141] As Figure 10As shown, the computer system 100 includes a Central Processing Unit (CPU) 1001, which can perform various appropriate actions and processes according to the program stored in the Read-Only Memory (ROM) 1002 or the program loaded from the storage section 1008 into the Random Access Memory (RAM) 1003, such as executing the method described in the above embodiments. In the RAM 1003, various programs and data required for system operation are also stored. The CPU 1001, ROM 1002, and RAM 1003 are connected to each other via a bus 1004. An Input / Output (I / O) interface 1005 is also connected to the bus 1004.

[0142] The following components are connected to the I / O interface 1005: an input section 1006 including a keyboard, a mouse, etc.; an output section 1007 including, for example, a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc. and a speaker, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as needed so that the computer program read from it can be installed into the storage section 1008 as needed.

[0143] Specifically, according to the embodiments of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network via the communication section 1009, and / or installed from the removable medium 1011. When the computer program is executed by the Central Processing Unit (CPU) 1001, various functions defined in the system of the present application are executed.

[0144] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0145] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0146] The units involved in the embodiments described in this application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not, in some cases, constitute a limitation on the unit itself.

[0147] One aspect of this application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the method for decomposing the DC internal resistance of a battery as described above. The computer-readable storage medium can be included in the electronic device described in the above embodiments, or can exist alone without being assembled into the electronic device.

[0148] Another aspect of this application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method for decomposing the DC internal resistance of a battery provided in the above various embodiments.

[0149] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention. It should be emphasized that the flowcharts and block diagrams in the drawings illustrate the system architectures, functions, and operations that the system according to various embodiments of this application may implement. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above module, program segment, or part of code includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0150] The modules and units involved in the embodiments described in this application can be implemented in software or in hardware, and the described modules and units can also be provided in a processor. Among them, the names of these modules and units do not, in some cases, constitute a limitation on the modules and units themselves.

[0151] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for decomposing the DC internal resistance of a battery, characterized in that, it includes: Obtaining the electrochemical impedance spectrum and the DC internal resistance spectrum of the battery; Based on the same equivalent circuit of the DC internal resistance, obtaining the ohmic impedance, electron impedance, charge transfer impedance and solid electrolyte interface impedance of the battery according to the electrochemical impedance spectrum and the DC internal resistance spectrum; Obtaining the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum; Obtaining the diffusion impedance of the battery according to the ohmic impedance, the electron impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance.

2. The method for decomposing the DC internal resistance of a battery according to claim 1, characterized in that, The step of obtaining the ohmic impedance, electron impedance, charge transfer impedance and solid electrolyte interface impedance of the battery according to the same equivalent circuit of the DC internal resistance and according to the electrochemical impedance spectrum and the DC internal resistance spectrum includes: Obtaining the ohmic impedance and the relaxation time according to the electrochemical impedance spectrum; Obtaining the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance, the DC internal resistance analysis formula includes a first DC internal resistance analysis formula and a second DC internal resistance analysis formula, and substituting the ohmic impedance and the relaxation time into the first DC internal resistance analysis formula; Fitting the DC internal resistance spectrum with the first DC internal resistance analysis formula with known partial parameters to obtain the ohmic impedance, the electron impedance, the charge transfer impedance and the solid electrolyte interface impedance.

3. The method for decomposing the DC internal resistance of a battery according to claim 2, characterized in that, The step of obtaining the relaxation time according to the electrochemical impedance spectrum includes: Performing relaxation time distribution analysis on the electrochemical impedance spectrum to obtain a relaxation time distribution spectrogram; Obtaining a plurality of the relaxation times according to the relaxation time distribution spectrogram.

4. The method for decomposing the DC internal resistance of a battery according to claim 3, characterized in that, The step of obtaining the DC internal resistance analysis formula of the battery according to the equivalent circuit of the DC internal resistance includes: Analyzing in combination with the equivalent circuit of the DC internal resistance and the relaxation time distribution spectrogram to obtain the first DC internal resistance analysis formula; Analyzing in combination with the equivalent circuit of the DC internal resistance and the DC internal resistance spectrum to obtain the second DC internal resistance analysis formula.

5. The method for decomposing the DC internal resistance of a battery according to claim 4, characterized in that, The equivalent circuit of the DC internal resistance includes a resistor and a plurality of resistor-capacitor parallel structures, and the resistor is connected in series with the plurality of resistor-capacitor parallel structures in sequence.

6. The method for decomposing the DC internal resistance of a battery according to claim 5, characterized in that, The first DC internal resistance analysis formula is: Among them, DCR(t) represents the DC internal resistance, R Ω represents the ohmic impedance, R k represents the electronic impedance, the charge transfer impedance or the solid electrolyte interface impedance, t represents time, τ k represents the relaxation time, R d represents the diffusion impedance, R ocv represents the open circuit voltage virtual impedance, and the value of k is an integer from 1 to n.

7. The method for decomposing the DC internal resistance of a battery according to claim 5, characterized in that, The second DC internal resistance analysis formula is: DCR = R Ω + R e + R sei + R ct + R d + R ocv ; Among them, DCR represents the DC internal resistance, R Ω represents the ohmic impedance, R e represents the electronic impedance, R sei represents the solid electrolyte interface impedance, R ct represents the charge transfer impedance, R d represents the diffusion impedance, R ocv represents the open circuit voltage virtual impedance.

8. The method for decomposing the DC internal resistance of a battery according to claim 1, characterized in that, The step of obtaining the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum includes: Obtain the DC internal resistance according to the DC internal resistance spectrum; Obtain the open-circuit voltage virtual impedance according to the DC internal resistance spectrum.

9. The method for decomposing the DC internal resistance of a battery according to claim 8, wherein, the calculation formula for the open-circuit voltage virtual impedance is: Among them, R ocv represents the virtual impedance of the open-circuit voltage, U1 represents the battery voltage before charge and discharge, U3 represents the open-circuit voltage after the battery is discharged directly and left standing for a preset time, and I represents the charge and discharge current.

10. The method for decomposing the DC internal resistance of a battery according to claim 7, wherein, the step of obtaining the diffusion impedance of the battery according to the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance includes: Substitute the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance into the second analytical formula of the DC internal resistance to calculate the diffusion impedance of the battery.

11. A device for decomposing the DC internal resistance of a battery, wherein, the device includes: a data acquisition module, configured to acquire the electrochemical impedance spectrum and the DC internal resistance spectrum of the battery; a first processing module, configured to obtain the ohmic impedance, the electronic impedance, the charge transfer impedance and the solid electrolyte interface impedance of the battery based on the same equivalent circuit of the DC internal resistance according to the electrochemical impedance spectrum and the DC internal resistance spectrum; a second processing module, configured to obtain the DC internal resistance and the open-circuit voltage virtual impedance of the battery according to the DC internal resistance spectrum; a third processing module, configured to obtain the diffusion impedance of the battery according to the ohmic impedance, the electronic impedance, the charge transfer impedance, the solid electrolyte interface impedance, the DC internal resistance and the open-circuit voltage virtual impedance.

12. An electronic device, wherein, it includes: one or more processors; a storage device, configured to store one or more programs, and when the one or more programs are executed by the one or more processors, enable the electronic device to implement the method for decomposing the DC internal resistance of a battery according to any one of claims 1 to 10.

13. A computer-readable storage medium, wherein, computer-readable instructions are stored thereon, and when the computer-readable instructions are executed by a processor of a computer, cause the computer to execute the method for decomposing the DC internal resistance of a battery according to any one of claims 1 to 10.

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