Calculation method for internal resistance conversion between lithium ion battery models

Abstract

The invention discloses a calculation method for internal resistance conversion between lithium ion battery models, which comprises the following steps: enabling electrochemical internal resistance to be equivalent to that multiple layers of pole pieces are connected in parallel through tabs, and calculating first electrochemical internal resistance of a battery with a known model and first electrochemical internal resistance of a battery with a target model according to parallel resistance; calculating a proportionality coefficient between the first electrochemical internal resistance of the known model battery and the first electrochemical internal resistance of the target model battery; multiplying the electrochemical internal resistance proportionality coefficient by the second electrochemical internal resistance of the battery with the known model, which is calculated through testing, to obtain the second electrochemical internal resistance of the battery with the target model; and adding the second electrochemical internal resistance of the target model battery and the structural internal resistance of the target model battery to obtain the total internal resistance of the target model battery. According to the method, the target model battery internal resistance of the same system is derived from the known model battery internal resistance, battery manufacturing cost consumption and time consumption are saved, and internal resistance conversion of different models of batteries can be rapidly completed.

Description

Technical Field

[0001] The invention relates to the technical field of battery internal resistance, and in particular to a calculation method for internal resistance conversion between lithium-ion battery models. Background Art

[0002] Battery internal resistance refers to the resistance encountered by current flowing through the battery when the battery is working, mainly including ohmic internal resistance and polarization internal resistance, among which polarization internal resistance includes electrochemical polarization and concentration polarization. Ohmic internal resistance mainly refers to the electrode material, electrolyte, diaphragm resistance and contact resistance of various parts, which is related to the size, structure, assembly, etc. of the battery. Polarization internal resistance: When the current passes through the electrode, the phenomenon that the electrode potential deviates from the equilibrium electrode potential is called electrode polarization. Polarization resistance refers to the internal resistance caused by polarization of the positive and negative electrodes of the battery during electrochemical reactions. The internal resistance of the battery is not a constant, and it changes with time during the charging and discharging process. This is because the composition of the active material, the concentration and temperature of the electrolyte are constantly changing. The ohmic internal resistance obeys Ohm's law. The polarization internal resistance increases with the increase of current density, but it is a nonlinear relationship. It often increases linearly with the increase of the logarithm of the current density. Internal resistance is an important technical indicator for measuring battery performance, which affects the discharge efficiency, thermal management and overall performance of the battery. A smaller internal resistance of a battery usually means that the battery has better large current discharge capability, while a larger internal resistance may cause the battery discharge operating voltage to decrease and the discharge time to shorten, thus affecting the battery performance and life.

[0003] Common methods for testing battery internal resistance are divided into two categories: AC internal resistance and DC internal resistance. AC internal resistance is measured by injecting a sinusoidal current signal I=I between the positive and negative electrodes of the battery. maxsin (2πft), and at the same time, the other two ends are used to detect the positive and negative electrodes of the battery to obtain a sinusoidal voltage signal U=U maxsin (2πft+Ψ), and then derive the AC impedance of the battery. The AC internal resistance is generally considered to be the ohmic internal resistance of the battery; in the case of DC internal resistance, a DC signal is applied to the battery to test the battery internal resistance, so the DC internal resistance is generally considered to be the ohmic internal resistance of the battery plus the polarization internal resistance. The common AC internal resistance test method is the high-frequency voltage drop method, that is, a 1KHz sinusoidal current, to test the voltage drop caused and calculate the internal resistance. Usually it is an enterprise OCV test and a voltage internal resistance meter tester. Common DC internal resistance test methods include DCR testing, that is, using different charge and discharge rate currents for 10s, recording the voltage and current, forming a straight line with a slope of internal resistance. The MCCF method uses a pulse charge and discharge current with a duration of 5s, records the voltage drop, and calculates the internal resistance. The HPPC method is the US PNGV regulation, which uses continuous charge and discharge pulses to test the voltage drop caused and calculate the internal resistance.

[0004] Patent CN115993552B discloses a battery internal resistance estimation method, which constructs internal resistance correction data sets corresponding to different battery life periods under different working conditions for experimental batteries of different brands and models; obtains the working condition information and brand and model information of the battery to be tested, calculates the battery life period of the battery to be tested, matches point A according to the correspondence between the battery working condition-brand-model and point A in the Bloom filter constructed in advance, and then obtains the internal resistance correction data set stored in the second database or the third database associated with point A; measures the internal resistance of the battery to be tested by the AC injection method, and determines whether the internal resistance correction data set obtained in step S2 is C f , if so, calculate C f With R s The sum of the values ​​is taken as the final corrected internal resistance of the battery to be tested; if not, calculate the distance D of the battery to be tested ij , then calculate D ij The distance D from each extreme point e carried in the acquired internal resistance correction data set ij The difference D is then used to calculate the internal resistance correction coefficient C corresponding to the extreme point e where D is the smallest. f With R s The sum of the values ​​is used as the final corrected internal resistance of the battery to be tested. This method calculates the internal resistance corresponding to different battery life periods under different working conditions, and requires a large amount of test data to establish a data set and repeatedly calibrate the coefficient to finally calculate the internal resistance. The data set test requires resources and time, and the correction coefficient has errors.

[0005] Patent CN108169685B discloses a method for estimating the AC internal resistance of a polymer lithium-ion battery. The AC internal resistance of the polymer lithium-ion battery is set as the sum of the internal resistance of the positive and negative electrode foils and the electrochemical internal resistance. The foil internal resistance is used to establish an equivalent figure consisting of a right triangle A, a parallelogram B, and a right triangle C connected in sequence. The internal resistance of each equivalent figure is calculated, and the internal resistance of the foil is R0=2*RA+R B ; The electrochemical internal resistance is calculated based on R ct常数 =R ct *S, and then correct the coating amount M to get the electrochemical internal resistance R ct , the calculation formula of the AC internal resistance of polymer lithium-ion batteries is expressed as R = R 0正 +R 0负 +R ct This method requires the establishment of equivalent graphics of positive and negative electrode foils, the calculation formula is complex, and the correction value needs to be optimized, and the calculation method is complex.

[0006] During the battery system design and customer demand assessment process, different customers have different requirements for battery models and capacities, which often involves the conversion of internal resistance between different models of the same system. If each customer evaluation is performed based on the model required by the customer, a lot of time and cost will be wasted. Therefore, when designing the battery, it is necessary to accurately and reliably evaluate the internal resistance of batteries of different models. During the battery development process, the system design is usually verified on a fixed battery model. Since different customers have different needs, the requirements for battery models are also different. Therefore, in the process of customer demand performance evaluation, it is often necessary to convert the battery internal resistance model. Therefore, a fast and accurate method for converting internal resistance between battery models is particularly important. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and provide a reliable and efficient method for calculating the internal resistance of lithium-ion batteries of different models. The method can derive the internal resistance of a target model battery of the same system from the internal resistance of a known model battery, save the cost and time consumption of battery production, and can quickly complete the conversion of the internal resistance of batteries of different models.

[0008] A method for calculating internal resistance conversion between lithium-ion battery models, comprising the steps of:

[0009] The electrochemical internal resistance is equivalent to a multi-layer electrode sheet connected in parallel through the electrode ears, and the first electrochemical internal resistance of the known model battery and the first electrochemical internal resistance of the target model battery are calculated from the parallel resistance;

[0010] Calculate the proportionality coefficient between the first electrochemical internal resistance of a battery of a known model and the first electrochemical internal resistance of a battery of a target model;

[0011] The second electrochemical internal resistance of the target battery is obtained by multiplying the electrochemical internal resistance proportionality coefficient by the second electrochemical internal resistance of the battery of the known model calculated through testing;

[0012] The second electrochemical internal resistance of the target model battery is added to the structural internal resistance of the target model battery to obtain the total internal resistance of the target model battery.

[0013] The proportionality coefficient is obtained by dividing the first electrochemical internal resistance of a battery of a known model by the first electrochemical internal resistance of a battery of a target model.

[0014] Among them, the electrochemical internal resistance is equivalent to multiple layers of pole pieces connected in parallel through pole ears, and the first electrochemical internal resistance of a battery of a known model and the first electrochemical internal resistance of a battery of a target model are calculated by the parallel resistance. The first electrochemical internal resistance and the first electrochemical internal resistance of a battery of a target model are calculated based on the number of pole piece layers in the battery, the area of ​​a single pole piece, and the internal resistance of the pole piece unit.

[0015] The calculation formula of the first electrochemical internal resistance of the target model battery / known model battery is:

[0016] R 电化学1 =(r*s) / n, where n is the number of electrode layers in the battery, r is the internal resistance per unit area of ​​the electrode, s is the area of ​​a single electrode, and Relectrochemical is the electrochemical internal resistance of the target model battery / known model battery.

[0017] The second electrochemical internal resistance of the known type of battery is calculated by the following formula:

[0018] R 电化学2 =(1-△V 欧姆 / △V)*R;

[0019] Where R is the total internal resistance of a battery of known model, △V 欧姆 It represents the ohmic voltage drop caused by the structural internal resistance Rstructure, △V represents the total voltage drop of the battery caused by the battery internal resistance R, and I represents the pulse current of the test.

[0020] Wherein, the ohmic voltage drop is calculated by the following formula:

[0021] △V ohm = I*R structure;

[0022] Among them, the R structure is the structural internal resistance of a battery of a known model, which is obtained through simulation calculation.

[0023] The total internal resistance of the battery of the known model is obtained through HPPC testing. When performing the HPPC test, the initial SOC voltage V0 and the post-pulse voltage Vt of each battery of the known model are recorded, and the total internal resistance of the battery of the known model is calculated by dividing the total voltage drop △V of the battery by the pulse current I.

[0024] Wherein, the structural internal resistance of the target model battery is obtained through simulation calculation.

[0025] The number of electrode layers and / or the area of ​​a single electrode of the known model battery and the target model battery are the same or different.

[0026] Among them, the electrode groups of the known model battery and the target model battery are one of a wound electrode group and a laminated electrode group.

[0027] The method of the present invention can deduce the internal resistance of a target battery model of the same system from the internal resistance of a battery of a known model, thereby saving the cost and time consumption of battery production, and can quickly complete the conversion of the internal resistance of batteries of different models. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of a method for calculating internal resistance conversion between lithium-ion battery models. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The calculation method for converting the internal resistance between lithium-ion battery models in the implementation of the present invention is used to calculate or estimate the internal resistance of batteries of different models. The first electrochemical internal resistance of a known model battery and a target model battery is calculated by the size difference of the battery models, and the electrochemical internal resistance proportionality coefficient is calculated. Then, based on the electrochemical internal resistance proportionality coefficient and the second electrochemical internal resistance of the known model battery, the second electrochemical internal resistance of the target model battery is derived. Finally, the second electrochemical internal resistance of the target model battery is added to its structural internal resistance to obtain the total internal resistance of the target model battery.

[0031] See also Figure 1 As shown, a method for calculating the internal resistance conversion between lithium-ion battery models includes the steps of:

[0032] S1. The electrochemical internal resistance is equivalent to a multi-layer electrode sheet connected in parallel through the electrode ears, and the first electrochemical internal resistance of the known model battery and the first electrochemical internal resistance of the target model battery are calculated from the parallel resistance;

[0033] S2. Calculate the proportionality coefficient between the first electrochemical internal resistance of a known battery model and the first electrochemical internal resistance of a target battery model;

[0034] S3. multiplying the electrochemical internal resistance proportionality coefficient by the second electrochemical internal resistance of the known model battery calculated through testing to obtain the second electrochemical internal resistance of the target model battery;

[0035] S4. Add the second electrochemical internal resistance of the target model battery and the structural internal resistance of the target model battery to obtain the total internal resistance of the target model battery.

[0036] The proportionality coefficient is obtained by dividing the first electrochemical internal resistance of a battery of a known model by the first electrochemical internal resistance of a battery of a target model.

[0037] Among them, the electrochemical internal resistance is equivalent to multiple layers of pole pieces connected in parallel through pole ears, and the first electrochemical internal resistance of a battery of a known model and the first electrochemical internal resistance of a battery of a target model are calculated by the parallel resistance. The first electrochemical internal resistance and the first electrochemical internal resistance of a battery of a target model are calculated based on the number of pole piece layers in the battery, the area of ​​a single pole piece, and the internal resistance of the pole piece unit.

[0038] Specifically, the calculation formula for the first electrochemical internal resistance of the target model battery / known model battery is:

[0039] R 电化学1=(r*s) / n, where n is the number of electrode layers in the battery, r is the internal resistance per unit area of ​​the electrode, the same system batteries have the same r, s is the area of ​​a single electrode, and Relectrochemical is the electrochemical internal resistance of the target model battery / known model battery.

[0040] For lithium-ion batteries, the electrochemical internal resistance, whether the battery is wound or stacked, can be equivalent to each layer of pole pieces connected in parallel through the pole ears, and is calculated by the parallel resistance;

[0041] The electrochemical internal resistance of the target model battery / known model battery can be calculated by the following formula:

[0042] 1 / R 电化学1 =1 / R1+1 / R2+1 / R3+……+1 / R n , where R1, R2, R3, ... R n The resistance of each layer of the battery is approximately equal;

[0043] The above formula can be transformed into formula R 电化学1 =(r*s) / n.

[0044] Thus, the first electrochemical internal resistance R of a battery of a known model can be calculated by the above formula in the embodiment of the present application. 电化学1 And the first electrochemical internal resistance R' of the target battery 电化学1 , the electrochemical internal resistance ratio coefficient k=R' of the target battery and the known model battery 电化学1 / R 电化学1 =[r'*s' / n'] / [r*s / n];

[0045] Among them, r', s', and n' are the internal resistance per unit area of ​​the battery electrode, the area of ​​a single electrode, and the number of electrode layers in the battery of the target model battery, respectively; r, s, and n are the internal resistance per unit area of ​​the battery electrode, the area of ​​a single electrode, and the number of electrode layers in the battery of the known model battery, respectively.

[0046] In the embodiment of the present application, in step S3, the second electrochemical internal resistance R' of the target model battery can be calculated by the following formula: 电化学2 =k*R 电化学2 , R 电化学2 is the second electrochemical internal resistance of a battery of known model;

[0047] R' 电化学2 =[r'*s' / n'] / [r*s / n]*(1-I*R 结构 / △V)*R.

[0048] In the embodiment of the present application, in step S4, the total internal resistance R' of the target model battery is equal to the second electrochemical internal resistance R' of the target model battery. 电化学2 And its structural internal resistance R'结构 The sum of is as follows:

[0049] R'=R' 电化学 +R' 结构 Substituting the above formula into the target model battery internal resistance

[0050] R'=[r'*s' / n'] / [r*s / n]*(1-I*R 结构 / △V)*R+R' 结构 .

[0051] In this way, the internal resistance of the target model at different SOCs can be calculated by using the internal resistance of the known model battery at different SOCs.

[0052] When calculating the second electrochemical internal resistance of a battery of a known model, the present invention utilizes the battery internal resistance R=△V / I to divide the battery internal resistance into ohmic internal resistance and electrochemical polarization internal resistance, wherein the ohmic internal resistance is caused by the internal resistance of structural parts related to the battery electrical connection, and the electrochemical internal resistance, whether the battery is in the form of winding or stacked sheets, can be equivalent to a plurality of layers of pole pieces connected in parallel through pole ears, and calculated by parallel resistance, so as to calculate the second electrochemical internal resistance of the battery of the known model and the target model by equating the electrochemical internal resistance of the battery of the known model and the target model to each layer of pole pieces connected in parallel.

[0053] In the embodiment of the present application, the ohmic voltage drop caused by the internal resistance of the battery structure and the total voltage drop caused by the internal resistance of the battery are used to deduce the proportion of the electrochemical internal resistance to the battery internal resistance, and then the second electrochemical internal resistance of a battery of a known model is calculated.

[0054] Specifically, the second electrochemical internal resistance of the known type of battery is calculated by the following formula: R 电化学2 =(1-△V 欧姆 / △V)*R; where R is the total internal resistance of a battery of known model, △V 欧姆 It represents the ohmic voltage drop caused by the structural internal resistance Rstructure, △V represents the total voltage drop of the battery caused by the battery internal resistance R, and I represents the pulse current of the test.

[0055] Wherein, the ohmic voltage drop is calculated by the following formula: △V 欧姆 =I*R 结构 ; Among them, the R structure is the structural internal resistance of a battery of a known model, which is obtained through simulation calculation.

[0056] In the embodiment of the present application, the total internal resistance of the battery of known model is obtained through HPPC test. When performing HPPC test, the initial SOC voltage V0 and the post-pulse voltage Vt of each battery of known model are recorded, and the total internal resistance of the battery of known model is calculated by dividing the total voltage drop △V of the battery by the pulse current I.

[0057] The total internal resistance R of a battery of a known battery type in the present application embodiment is calculated by HPPC DC pulse test, wherein the internal resistance R of a battery of a known battery type is 结构 From the simulation, it is found that the electrochemical internal resistance R of a known battery model is 电化学 Subtract the ohmic internal resistance R from the total internal resistance R of the battery 欧姆 It is concluded that R 电化学 =RR 欧姆 , the ohmic internal resistance R of a known battery model 欧姆 The internal resistance R 结构 The ohmic voltage drop △V caused 欧姆 The ratio of the total voltage drop △V of the battery multiplied by the total internal resistance R of the battery is obtained, that is, the ohmic internal resistance R of the known battery model 欧姆 =(△V 欧姆 / △V)*R;

[0058] Where △V 欧姆 =I*R 结构 , thus obtaining the second electrochemical internal resistance R of the known battery model 电化学2 =(1-I*R 结构 / △V)*R.

[0059] In the embodiment of the present application, the structural internal resistance of the target model battery is obtained by simulation calculation. In the embodiment of the present application, the number of electrode layers and / or the single electrode area of ​​the known model battery and the target model battery are the same or different. In the embodiment of the present application, the electrode group of the known model battery and the target model battery is a wound electrode group or a laminated electrode group.

[0060] Experimental example:

[0061] Given a square A battery, find the internal resistance of a square B battery of the same system design target. Given the battery model, perform the HPPC test and record the initial voltage V0 of each SOC and the pulse voltage V for 10s. t , and calculate the internal resistance R by dividing the pulse voltage difference △V by the pulse current I, and obtain the internal resistance of the known square A model battery. The internal resistance R of the square A model battery structure is calculated by simulation. 结构 The internal resistance R' of the square B battery structure is 0.1766mΩ 结构 0.0719mΩ

[0062] S1. Calculation of the first electrochemical internal resistance of the target battery and the known battery;

[0063] From the battery system design, it can be known that for the known square type A battery, the number of electrode layers in the battery is n=51, the area of ​​the battery single-piece electrode is s=288*83.5, and the internal resistance per unit area of ​​the electrode is r; for the target square type B battery, the number of electrode layers in the battery is n=79, the area of ​​the battery single-piece electrode is s=190*101, and the internal resistance per unit area of ​​the electrode is r'. Since the system is the same, the internal resistance per unit area of ​​the known square type A battery electrode is r' equal to the internal resistance per unit area of ​​the target square type B battery electrode; by calculation:

[0064] The first electrochemical internal resistance R of the square A type battery is known 电化学1 =r*(288*83.5) / 51, for the first electrochemical internal resistance R' of the target square B type battery 电化学1 =r'*(190*101) / 158,

[0065] S2. The first electrochemical internal resistance R based on the standard battery and the known battery 电化学1 , R' 电化学1 , calculate the electrochemical internal resistance ratio coefficient k between the target model battery and the known model battery = [r'*(190*101) / 158] / [r*(288*83.5) / 51] = 0.258.

[0066] S3. Calculation of the second electrochemical internal resistance of the target model battery:

[0067] The second electrochemical internal resistance of the target square B type battery is calculated as follows:

[0068] R' 电化学2 =0.258*(1-0.1766 / 1000*I / (V0-V t ))*R:

[0069] Among them, the second electrochemical internal resistance of the known square A type battery is calculated as follows:

[0070] The internal resistance R of the square A type battery structure 结构 Multiply by the test process pulse current I to get the ohmic voltage drop △V 欧姆 , and △V 欧姆 =I*R 结构 , using the total voltage drop during the battery pulse process △V=V0-V t , calculate the second electrochemical internal resistance R of the known square A battery 电化学2 =(1-0.1766 / 1000*I / (V0-V t ))*R.

[0071] The calculation results are shown in Table 1 and Table 2. It is known that the A type battery △V 欧姆 and R 电化学 .

[0072] S4. Calculation of target battery total internal resistance:

[0073] The total internal resistance of the target battery type B is calculated as follows:

[0074] R' B =0.258*(1-0.1766 / 1000*I / (V0-V t ))*R+0.0719.

[0075] In this way, by knowing the internal resistance of the A-type battery at different SOCs, the internal resistance of the target B-type battery at different SOCs can be calculated. The discharge and charge internal resistance R' of the target square B-type battery is calculated as shown in Table 1 and Table 2.

[0076] Table 1 Comparison of measured and calculated internal resistance of different models of pulse discharge

[0077]

[0078]

[0079] Table 2 Comparison of measured and calculated internal resistance of different models of pulse charging

[0080]

[0081] The present invention calculates the electrochemical internal resistance proportionality coefficient of the known and target model batteries through the difference in battery model sizes, and then obtains the second electrochemical internal resistance of the target model battery based on the battery electrochemical internal resistance proportionality coefficient and the multiplication of the second electrochemical internal resistance of the known model battery, and then obtains the total internal resistance of the target model battery, thereby solving the problem of internal resistance conversion calculation between battery models of the same system in the battery development process, being able to quickly and accurately evaluate the internal resistance of the target model battery to further complete related performance evaluation, and avoiding battery production cost and time consumption.

[0082] The method of the present invention splits the battery internal resistance into ohmic internal resistance and electrochemical internal resistance, and uses a parallel circuit to calculate the relationship between the electrochemical internal resistances of different models. The calculation method is simple and reliable, and is applicable to a variety of battery systems such as ternary systems, iron-lithium systems, etc., and is not limited to a single battery assembly form and battery size model. Whether the battery is in a wound or laminated form, whether it is a square battery or a soft-pack battery, it can achieve internal resistance conversion of different models and sizes, solves the problem of internal resistance conversion evaluation of batteries of different models, and can clearly and accurately calculate the DC internal resistance of batteries of different models and under different charge states.

[0083] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

[0084] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for calculating the internal resistance conversion between lithium-ion battery models, characterized in that: Includes steps: The electrochemical internal resistance is equivalent to a multi-layer electrode sheet connected in parallel through the electrode ears, and the first electrochemical internal resistance of the known model battery and the first electrochemical internal resistance of the target model battery are calculated from the parallel resistance; Calculate the proportionality coefficient between the first electrochemical internal resistance of a battery of a known model and the first electrochemical internal resistance of a battery of a target model; The second electrochemical internal resistance of the target battery is obtained by multiplying the electrochemical internal resistance proportionality coefficient by the second electrochemical internal resistance of the battery of the known model calculated through testing; The second electrochemical internal resistance of the target model battery is added to the structural internal resistance of the target model battery to obtain the total internal resistance of the target model battery.

2. The calculation method for converting internal resistance between lithium-ion battery models according to claim 1, characterized in that: The proportionality coefficient is obtained by dividing the first electrochemical internal resistance of a battery of a known model by the first electrochemical internal resistance of a battery of a target model.

3. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The electrochemical internal resistance is equivalent to multiple layers of pole pieces connected in parallel through pole ears, and the first electrochemical internal resistance of a battery of a known model and the first electrochemical internal resistance of a battery of a target model are calculated by the parallel resistance. The first electrochemical internal resistance and the first electrochemical internal resistance of a battery of a target model are calculated based on the number of pole piece layers in the battery, the area of ​​a single pole piece, and the internal resistance of the pole piece unit.

4. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The calculation formula of the first electrochemical internal resistance of the target model battery / known model battery is: R 电化学1 =(r*s) / n, where n is the number of electrode layers in the battery, r is the internal resistance per unit area of ​​the electrode, s is the area of ​​a single electrode, R 电化学 It is the electrochemical internal resistance of the target battery model / known battery model.

5. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The second electrochemical internal resistance of the known type of battery is calculated by the following formula: R 电化学2 =(1-△V 欧姆 / △V)*R; Where R is the total internal resistance of a battery of known model, △V 欧姆 Indicated by the structural internal resistance R 结构 The ohmic voltage drop caused by the battery is △V, which is the total voltage drop of the battery caused by the internal resistance R of the battery, and I is the pulse current of the test.

6. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 5, characterized in that: The ohmic voltage drop is calculated by the following formula: △V 欧姆 =I*R 结构； Among them, R 结构 is the structural internal resistance of a battery of known model, obtained through simulation calculation.

7. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 5, characterized in that: The total internal resistance of the known battery model is obtained by HPPC test. When the HPPC test is performed, the initial voltage V0 of each SOC of the known battery model, the voltage V after the pulse t , calculate the total internal resistance of a battery of known model by dividing the total battery voltage drop △V by the pulse current I.

8. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The structural internal resistance of the target model battery is obtained through simulation calculation.

9. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The number of electrode layers and / or the area of ​​a single electrode of the known model battery and the target model battery are the same or different.

10. The method for calculating the internal resistance conversion between lithium-ion battery models according to claim 1, characterized in that: The electrode groups of the known model battery and the target model battery are one of a wound electrode group and a laminated electrode group.

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