Lithium ion battery AC internal resistance calculation method based on physical parameter analysis

Abstract

The invention discloses a lithium ion battery AC internal resistance calculation method based on physical parameter analysis, and the method comprises the steps: obtaining the internal resistance of a positive pole piece, a negative pole piece, a connecting piece and a structural member, and adding the internal resistance to obtain the total internal resistance, namely the AC internal resistance of a lithium ion battery. The method has the following beneficial effects: high efficiency: the battery does not need to be manufactured, internal resistance evaluation can be completed in a design stage, and the period is shortened to 1-2 days; compared with actual detection data, the error of the step-by-step calculation model is less than 6%. And universality: compatibility with different materials (ternary materials, lithium iron phosphate and the like) and battery types is realized. The internal resistance problem point is accurately positioned, the optimization cost is reduced, and the internal resistance of the cell structure is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a method for calculating the AC internal resistance of lithium-ion batteries based on physical parameter analysis. Background Technology

[0002] As a core energy storage device in the new energy field, the internal resistance of lithium-ion batteries is one of the key parameters for measuring battery performance. It directly affects energy conversion efficiency, cycle life and safety, and is an important basis for battery design optimization and performance evaluation.

[0003] Currently, the industry's testing of the AC internal resistance of lithium-ion batteries mainly relies on experimental methods after the actual battery is manufactured: designers need to fabricate complete batteries according to different material formulations (such as ternary lithium, lithium iron phosphate, etc.) or structural designs (such as cylindrical, pouch, prismatic), and then test them using an internal resistance meter to compare the impact of different designs on the battery's internal resistance. However, this method has significant limitations: The cycle is lengthy: from electrode preparation, cell winding / stacking, packaging to liquid injection formation, the complete battery manufacturing cycle takes 7-15 days, which seriously restricts the efficiency of R&D iteration. High cost: Each design verification requires a large amount of raw materials (such as positive and negative electrode active materials, current collector foil, electrolyte, etc.) and equipment resources, and multiple sample preparations will significantly increase R&D costs; Insufficient flexibility: If the test results do not meet expectations, the design needs to be readjusted and the sample test needs to be repeated, causing the "design-verification-optimization" process to fall into an inefficient cycle.

[0004] For example, invention application CN117110922A discloses a method and system for testing the AC internal resistance of a lithium battery. The method includes: testing the lithium battery under test, collecting the initial AC voltage of the lithium battery under test when no predetermined excitation current is injected and the sampled AC voltage when a predetermined excitation current is injected; testing the compensation circuit, collecting the compensation AC voltage when a predetermined excitation current is injected into the compensation circuit; superimposing the compensation AC voltage and the sampled AC voltage in opposite phases to obtain the final AC voltage, and calculating the AC internal resistance of the lithium battery based on the final AC voltage, the predetermined excitation current, and the initial AC voltage.

[0005] Chinese patent application CN109799392A discloses a method for testing the AC internal resistance of a lithium battery. The method includes: a sinusoidal signal generation circuit generating a positive half-cycle sinusoidal voltage signal and inputting it to a signal conversion circuit; the signal conversion circuit converting the positive half-cycle sinusoidal voltage signal into a sinusoidal current and inputting it to a sampling channel switching circuit; the sampling channel switching circuit selecting the channel through which the sinusoidal current flows, and inputting the generated sinusoidal voltage signal to a phase comparison and measurement circuit and a DSP sampling and control circuit respectively; the phase comparison and measurement circuit generating two capture signals and inputting them to the DSP sampling and control circuit; the DSP sampling and control circuit sampling the sinusoidal voltage signal, capturing and calculating the time difference between the high levels of the two capture signals; calculating the impedance and power factor using the AD values ​​and time differences from different channels, and then calculating the AC internal resistance using the impedance and power factor.

[0006] With the rapid growth in demand for high-energy-density, long-life batteries from fields such as new energy vehicles and energy storage systems, traditional internal resistance evaluation methods that rely on physical testing are no longer sufficient to meet the industry's urgent requirements for R&D efficiency. Therefore, there is an urgent need for a rapid internal resistance calculation method based on material parameters and structural characteristics that does not require the fabrication of physical batteries, in order to shorten the verification cycle, reduce R&D costs, and promote rapid innovation in lithium-ion battery technology. Summary of the Invention

[0007] To address the aforementioned shortcomings in the prior art, this invention provides a method for calculating the AC internal resistance of lithium-ion batteries based on physical parameter analysis.

[0008] A method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis. The lithium-ion battery includes a positive electrode, a negative electrode, a connector, and a structural component. The positive electrode includes a positive current collector, a positive electrode coating, and a positive electrode tab. The negative electrode includes a negative current collector, a negative electrode coating, and a negative electrode tab. The method for calculating the AC internal resistance of the lithium-ion battery includes the following steps: obtaining the internal resistances of the positive electrode, the negative electrode, the connector, and the structural component respectively, and adding them together to obtain the total internal resistance, which is the AC internal resistance of the lithium-ion battery. When obtaining the internal resistance of the positive and negative electrode sheets, the internal resistance of the positive and negative current collectors is calculated based on the thermodynamic model of the current distribution of the electrode tabs. The internal resistance of the positive and negative electrode dressings is calculated by measuring the resistivity of the dressing layer and the resistivity of the interface surface, and then based on the double-sided parallel model and the interface resistance theory. The internal resistance of the positive electrode sheet is the sum of the internal resistance of the positive current collector, the positive electrode dressing, and the positive electrode tab. The internal resistance of the negative electrode sheet is the sum of the internal resistance of the negative current collector, the negative electrode dressing, and the negative electrode tab. The internal resistance of a connector is the product of its resistivity and its length, divided by its cross-sectional area. The internal resistance of the structural components was obtained through actual measurement.

[0009] Preferably, the connector includes a separately welded electrode lug or an adapter connected to the cover plate; The structural components include a housing, a cap, and a cover plate, wherein the housing is a steel or aluminum shell.

[0010] Preferably, the positive and negative electrodes are either fully tabbed or tabless structures, and the internal resistance of the positive and negative current collectors is calculated using the formula: R 集流体 =ρ 集流体 L 集流体 / (3S 集流体 ), where R 集流体 For the current collector internal resistance, ρ 集流体 Let L be the resistivity of the current collector. 集流体 S is the length of the current collector. 集流体 The cross-sectional area of ​​the current collector is given. When calculating the positive current collector, all parameters are the corresponding parameters of the positive current collector, and when calculating the negative current collector, all parameters are the corresponding parameters of the negative current collector.

[0011] Preferably, the positive and negative electrode plates have a multi-tab structure, and the internal resistance of the positive and negative current collectors is calculated using the formula: Rx = R 集流体 / (4X 2 ), where R 集流体 Rx represents the internal resistance of the current collector, X represents the number of tabs on the current collector, and Rx represents the internal resistance of the current collector under X tabs. When calculating the positive current collector, all parameters are the corresponding parameters of the positive current collector, and when calculating the negative current collector, all parameters are the corresponding parameters of the negative current collector.

[0012] Preferably, in the double-sided parallel model, the material ratio, areal density, and thickness of the double-sided dressing layers are consistent.

[0013] Preferably, the formula for calculating the internal resistance of the positive electrode dressing and the negative electrode dressing is: R 涂敷 =(1 / 2) ×(ρ 敷料 / S 敷料 +ρ 界面 / S 敷料 ), where R 涂敷 ρ is the sum of the internal resistance of the dressing layer and the internal resistance of the interface. 敷料 ρ is the resistivity of the dressing layer. 界面 S is the interfacial resistivity. 敷料 The parameters are the corresponding parameters for the positive electrode dressing when calculating the positive electrode dressing, and the parameters are the corresponding parameters for the negative electrode dressing when calculating the negative electrode dressing.

[0014] Preferably, when calculating the internal resistance of the positive and negative tabs, the internal resistance of a single tab is R. 单极耳 The internal resistance of multiple electrodes stacked in parallel is R. 极耳 R 单极耳 =ρ 极耳 L极耳 / S 极耳 , where ρ 极耳 L is the resistivity of the tab foil material. 极耳 S is the length of the electrode lug. 极耳 R is the cross-sectional area of ​​the pole piece. 极耳 =R 单极耳 / X, where X is the number of electrodes. When calculating the positive electrode tab, all parameters are the corresponding parameters for the positive electrode tab; when calculating the negative electrode tab, all parameters are the corresponding parameters for the negative electrode tab.

[0015] Preferably, the materials for the positive electrode current collector and the negative electrode current collector are each independently selected from at least one of aluminum foil, copper foil, and stainless steel foil.

[0016] Preferably, the lithium-ion battery is a ternary lithium battery, a lithium iron phosphate battery, a lithium manganese oxide battery, a lithium manganese iron phosphate battery, or a lithium-rich manganese-based battery.

[0017] Preferably, the lithium-ion battery is a cylindrical battery, a pouch battery, or a prismatic battery.

[0018] Beneficial effects of this invention: 1. High efficiency: No need to manufacture batteries, internal resistance assessment can be completed during the design stage, shortening the cycle to 1-2 days.

[0019] 2. High precision: Compared with actual detection data, the step-by-step calculation model error is <6%.

[0020] 3. Versatility: Compatible with different materials (ternary lithium, lithium iron phosphate, etc.) and battery types.

[0021] 4. Accurately pinpointing internal resistance issues reduces optimization costs and is beneficial for improving the internal resistance of the battery cell structure. Attached Figure Description

[0022] Figure 1 This is a diagram showing the internal resistance composition of a lithium-ion battery.

[0023] Figure 2 This is a schematic diagram of the electrode sheet. Detailed Implementation

[0024] A rapid calculation method for the AC internal resistance of a lithium-ion battery based on physical parameter analysis is disclosed. The lithium-ion battery comprises a current collector, an electrode coating layer (i.e., the active material layer of the positive or negative electrode), tabs, connectors, and structural components. The current collector is made of aluminum foil, copper foil, or stainless steel foil. The electrode coating layer material is a positive electrode material such as ternary lithium, lithium iron phosphate, lithium manganese oxide, lithium manganese iron phosphate, or lithium-rich manganese-based material, and a negative electrode material such as graphite, hard carbon, soft carbon, or silicon carbon. The connectors include separately welded tabs or adapters connected to a cover plate. The structural components are a shell, a cap, or a cover plate.

[0025] like Figure 1 The diagram shown illustrates the composition of the AC internal resistance of a lithium-ion battery.

[0026] The calculation method includes the following steps: Step 1: Based on the thermodynamic model of the electrode current distribution, calculate the internal resistance of the current collector.

[0027] (1) All-pole structure: R 集流体 =ρ 集流体 L 集流体 / (3S 集流体 ), where R 集流体 For the current collector internal resistance, ρ 集流体 L is the resistivity. 集流体 S is the length. 集流体 For the cross-sectional area, all parameters used in calculating the positive electrode current collector are the corresponding parameters for the positive electrode current collector, and all parameters used in calculating the negative electrode current collector are the corresponding parameters for the negative electrode current collector. The derivation of the formula for calculating calorific value includes the following steps: Full-tab batteries, such as large cylindrical batteries, have a certain height of current collector left on top after coating for smoothing; tabless batteries, such as 18650 batteries, use individually welded tabs. The current flow is different in full-tab and tabless structures.

[0028] Formulas for calculating the structure of a multipole or electrodeless ear: Q=I 2 R 集流体 t; Q = Q1 + Q2 + ... + Q n ; I 2 R 集流体 t=((I / n) 2 +(2I / n) 2 ……+(nI / n) 2 )×ρL / (nS)×t; R 集流体 = =ρL / (3S).

[0029] Where Q represents heat generation, I represents current, and R... 集流体 The current collector represents the internal resistance, t represents time, and n represents the current collector being divided into n groups.

[0030] (2) Multipole structure (X poles): Rx = R 集流体 / (4X 2 ).

[0031] Formula for calculating the structure of a multi-electrode (equally divided into X electrodes): One electrode internal resistance R1: 1 / R1=1 / (R集流体 / (4X); R1=R 集流体 / (4X 2 )=R 集流体 / 4.

[0032] Multiple electrode internal resistance Rx: 1 / Rx=1 / (R 集流体 / (4X))+1 / (R 集流体 / (4X))+……+1 / (R 集流体 / (4X)), a total of X groups 1 / (R) 集流体 Add (4X) together; Rx=R 集流体 / (4X 2 ); Rx represents the internal resistance of the current collector under X tabs. When calculating the positive current collector, all parameters are the corresponding parameters of the positive current collector; when calculating the negative current collector, all parameters are the corresponding parameters of the negative current collector.

[0033] Step 2: Bifacial parallel model + theoretical estimation of interface resistance like Figure 2 The diagram shows the structure of the electrode sheet. Both sides of the current collector in the positive and negative electrodes of a lithium battery are coated with a coating layer, hence the term "double-sided." Similarly, the interface is formed between the coating layer and both sides of the current collector. The internal resistance of the coating areas on both sides of the current collector is connected in parallel through the current collector itself. The interface resistance refers to the resistance between the coating layer and the current collector.

[0034] In step 2, the material ratio, surface density, and thickness of the double-sided parallel model are consistent.

[0035] The resistivity ρ of the positive / negative electrode dressing layer was measured using a four-probe electrode resistance testing system (four-probe resistance tester). 敷料 and interfacial resistivity (resistivity between the dressing layer and the current collector) ρ 界面 The sum of the internal resistance of the dressing layer and the interface is R. 涂覆 .

[0036] R 涂敷 =(1 / 2)×((ρ 敷料 / L 敷料 )×L 敷料 / S 敷料 +(ρ 界面 / L 界面 )×L 界面 / S 敷料 )=(1 / 2)×(ρ 敷料 / S 敷料 +ρ 界面 / S 敷料 ); Among them, L敷料 L represents the thickness of the dressing layer. 界面 S is the distance of the electronic transmission interface. 敷料 The parameters are the corresponding parameters for the positive electrode dressing when calculating the positive electrode dressing, and the parameters are the corresponding parameters for the negative electrode dressing when calculating the negative electrode dressing.

[0037] Step 3: Calculation of the internal resistance of the punched tab The internal resistance of a single electrode is R 单极耳 The internal resistance of multiple electrodes stacked in parallel is R. 极耳 .

[0038] R 单极耳 =ρ 极耳 L 极耳 / S 极耳 R 极耳 =R 单极耳 / X, where X is the number of electrodes.

[0039] Where, ρ 极耳 L is the resistivity of the tab foil material. 极耳 S is the length of the electrode lug. 极耳 For the cross-sectional area of ​​the electrode tab, all parameters are the corresponding parameters for the positive electrode tab when calculating the positive electrode tab, and all parameters are the corresponding parameters for the negative electrode tab when calculating the negative electrode tab.

[0040] Step 4: Electrode internal resistance, consisting of current collector, dressing layer, and punched tab internal resistance. The internal resistance of the positive electrode is R. 正极 The internal resistance of the negative electrode is R. 负极 The internal resistance of the positive current collector is R. 正极集流体 The internal resistance of the negative electrode current collector is R. 负极集流体 All of these are obtained through the method described in step 1. The internal resistance of the positive electrode coating layer and the interface is R. 正极涂敷 The internal resistance of the negative electrode coating layer and the interface is R. 负极涂敷 All of these are obtained through the method described in step 2. The internal resistance of the positive electrode tab is R. 正极耳 The internal resistance of the negative electrode tab is R. 负极耳 All of these are obtained through the method described in step 3.

[0041] R 正极 =R 正极集流体 +R 正极涂敷 +R 正极耳 ; R 负极 =R 负极集流体 +R 负极涂敷 +R 负极耳 .

[0042] Step 5: The connector includes a separately welded electrode lug or an adapter connected to the cover plate; the internal resistance of the connector is R. 连接件 The calculation method is as follows: Formula: R 连接件 =ρ 连接件 L 连接件 / S 连接件 ;R 连接件 ρ is the internal resistance of the connector. 连接件 L is the resistivity of the connector. 连接件 S is the length of the connector. 连接件 This refers to the cross-sectional area of ​​the connector.

[0043] Step 6: Measurement of internal resistance of structural components The internal resistance of structural components such as steel shell, aluminum shell, cap, and cover plate is directly measured using an internal resistance meter. The sum of the internal resistances of each structural component is the internal resistance R of the structural component. 结构件 .

[0044] The total internal resistance of a lithium-ion battery is R. 总 R 总 =R 正极 +R 负极 +R 连接件 +R 结构件 .

[0045] The following embodiments are calculated according to the above method and steps.

[0046] Example 1 The cylindrical 26700 battery has a 15μm aluminum foil current collector for the positive electrode and an 8μm copper foil current collector for the negative electrode. The positive electrode material is lithium iron phosphate, and the negative electrode material is graphite. The core adopts a structure with positive and negative double tabs welded together and connected to the cap. The shell is a 26×74mm steel shell, and the cap is a 25.4×4.45mm four-hole cap. The positive electrode sheet is 62mm wide, and each section of the coating layer is 460mm long. The negative electrode is 64mm wide, and the coating layer is 1468mm long.

[0047] The positive electrode tab is located at the third division position, X=2; the negative electrode sheet is welded with tabs on both sides, which is equivalent to the electrode sheet being divided into two segments, X=1.

[0048] (1) Current collector internal resistance: (2) Resistance within the coating area: (3) Internal resistance of the electrode: R 正极 =0.89 + 0.0291 = 0.9191 mΩ; R 负极 =4.27+0.00282=4.27282mΩ.

[0049] (4) Connecting piece: (5) Internal resistance of structural components: (6) Total internal resistance: The actual median internal resistance after injection was obtained by measuring the internal resistance meter. An error greater than the predicted value is considered a positive error, and an error smaller than the predicted value is considered a negative error. The same applies below.

[0050] The calculated total internal resistance value has an error of 4.78% compared to the actual measured total internal resistance value.

[0051] Example 2 The cylindrical 26700 battery has an aluminum foil current collector for the positive electrode and a copper foil current collector for the negative electrode. The positive electrode material is lithium iron phosphate, and the negative electrode material is graphite. The core adopts a structure with positive and negative double tabs welded together and connected to the cap. The shell is a 26×74mm steel shell, and the cap is a 25.4×4.45mm four-hole cap. The positive electrode sheet is 62mm wide, and each section of the coating layer is 460mm long. The negative electrode is 64mm wide, and each section of the coating layer is 489mm long.

[0052] The positive electrode tab is located at the third division position, X=2; the negative electrode tab is located at the third division position, X=2.

[0053] (1) Current collector internal resistance: (2) Resistance within the coating area: (3) Internal resistance of the electrode: R 正极 =0.89 + 0.0291 = 0.919 mΩ; R 负极 =1.06+0.00282=1.063mΩ.

[0054] (4) Connecting piece: (5) Internal resistance of structural components: (6) Total internal resistance: The calculated total internal resistance value has an error of 5.27% compared to the actual measured total internal resistance value.

[0055] Example 3 The 133204 soft-pack lithium iron phosphate battery has a 13μm aluminum foil as the positive current collector and a 6μm copper foil as the negative current collector. The positive electrode material is lithium iron phosphate, and the negative electrode material is graphite. The stacked core adopts a stacked structure with 25 positive electrode sheets and 26 negative electrode sheets, each sheet with one tab. The positive electrode tab size is 43.5mm×30mm×0.2mm, and the negative electrode tab size is 43.5mm×30mm×0.15mm. The positive electrode sheet size is 180×127mm, and the negative electrode sheet size is 184×130mm.

[0056] (1) Current collector internal resistance: (2) Resistance within the coating area: Dressing resistance and interface resistance: tab resistance: (3) Internal resistance of the electrode: R 正极 =0.0412+0.16+0.065=0.2662mΩ; R 负极 =0.0529+0.011+0.073=0.1369mΩ.

[0057] (4) Connecting piece (positive electrode 43.5mm×30mm×0.2mm, negative electrode 43.5mm×30mm×0.15mm): (5) Total internal resistance: The calculated total internal resistance value has an error of -0.59% compared to the actual measured total internal resistance value.

[0058] Example 4 The square 54173207-206Ah lithium iron phosphate battery has a 15μm aluminum foil as the positive current collector and an 8μm copper foil as the negative current collector. The positive electrode material is lithium iron phosphate, and the negative electrode material is graphite. The core adopts a wound structure. There are 37 positive electrode tabs and 38 negative electrode tabs. The positive electrode sheet is 187mm wide and 11.701m long. The negative electrode sheet is 192mm wide and 12.047m long.

[0059] (1) Current collector internal resistance: (2) Resistance within the coating area: Dressing resistance and interface resistance: tab resistance: (3) Internal resistance of the electrode: R 正极 =0.0072+0.0014+0.04=0.0486mΩ; R 负极 =0.0079+0.00011+0.048=0.056mΩ.

[0060] (4) Connectors: (5) Internal resistance of structural components: (6) Total internal resistance: The calculated total internal resistance value has an error of 0.67% compared to the actual measured total internal resistance value.

[0061] In summary, the internal resistance of the lithium-ion battery calculated by the theoretical method of this application is close to the actual measured value, with an error of less than 6%, which proves the accuracy of the theoretical calculation method of this application.

Claims

1. A method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis, wherein the lithium-ion battery includes a positive electrode, a negative electrode, connectors, and structural components; the positive electrode includes a positive current collector, a positive electrode coating, and a positive electrode tab; and the negative electrode includes a negative current collector, a negative electrode coating, and a negative electrode tab; characterized in that... The method for calculating the AC internal resistance of a lithium-ion battery includes the following steps: obtaining the internal resistances of the positive electrode, negative electrode, connector, and structural component respectively, and adding them together to obtain the total internal resistance, which is the AC internal resistance of the lithium-ion battery. When obtaining the internal resistance of the positive and negative electrode sheets, the internal resistance of the positive and negative current collectors is calculated based on the thermodynamic model of the current distribution of the electrode tabs. The internal resistance of the positive and negative electrode dressings is calculated by measuring the resistivity of the dressing layer and the resistivity of the interface surface, and then based on the double-sided parallel model and the interface resistance theory. The internal resistance of the positive electrode sheet is the sum of the internal resistance of the positive current collector, the positive electrode dressing, and the positive electrode tab. The internal resistance of the negative electrode sheet is the sum of the internal resistance of the negative current collector, the negative electrode dressing, and the negative electrode tab. The internal resistance of a connector is the product of its resistivity and its length, divided by its cross-sectional area. The internal resistance of the structural components was obtained through actual measurement.

2. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, The connector includes separately welded electrode lugs or adapters connected to the cover plate; The structural components include a housing, a cap, and a cover plate, wherein the housing is a steel or aluminum shell.

3. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, The positive and negative electrodes can be either fully tabbed or tabless. The formula for calculating the internal resistance of the positive and negative current collectors is: R 集流体 =ρ 集流体 L 集流体 / (3S 集流体 ), where R 集流体 For the current collector internal resistance, ρ 集流体 Let L be the resistivity of the current collector. 集流体 S is the length of the current collector. 集流体 The cross-sectional area of ​​the current collector is given. When calculating the positive current collector, all parameters are the corresponding parameters of the positive current collector, and when calculating the negative current collector, all parameters are the corresponding parameters of the negative current collector.

4. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, The positive and negative electrodes have a multi-tab structure. The formula for calculating the internal resistance of the positive and negative current collectors is: Rx = R 集流体 / (4X 2 ), where R 集流体 Rx represents the internal resistance of the current collector, X represents the number of tabs on the current collector, and Rx represents the internal resistance of the current collector under X tabs. When calculating the positive current collector, all parameters are the corresponding parameters of the positive current collector, and when calculating the negative current collector, all parameters are the corresponding parameters of the negative current collector.

5. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, In the double-sided parallel model, the material ratio, areal density, and thickness of the double-sided dressing layers are all the same.

6. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, The formula for calculating the internal resistance of positive and negative electrode dressings is: R 涂敷 =(1 / 2) ×(ρ 敷料 / S 敷料 +ρ 界面 / S 敷料 ), where R 涂敷 ρ is the sum of the internal resistance of the dressing layer and the internal resistance of the interface. 敷料 ρ is the resistivity of the dressing layer. 界面 S is the interfacial resistivity. 敷料 The parameters are the corresponding parameters for the positive electrode dressing when calculating the positive electrode dressing, and the parameters are the corresponding parameters for the negative electrode dressing when calculating the negative electrode dressing.

7. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, When calculating the internal resistance of the positive and negative tabs, the internal resistance of a single tab is R. 单极耳 The internal resistance of multiple electrodes stacked in parallel is R. 极耳 R 单极耳 =ρ 极耳 L 极耳 / S 极耳 , where ρ 极耳 L is the resistivity of the tab foil material. 极耳 S is the length of the electrode lug. 极耳 R is the cross-sectional area of ​​the electrode. 极耳 =R 单极耳 / X, where X is the number of electrodes. When calculating the positive electrode tab, all parameters are the corresponding parameters for the positive electrode tab; when calculating the negative electrode tab, all parameters are the corresponding parameters for the negative electrode tab.

8. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, The materials of the positive electrode current collector and the negative electrode current collector are each independently selected from at least one of aluminum foil, copper foil and stainless steel foil.

9. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, Lithium-ion batteries include ternary lithium batteries, lithium iron phosphate batteries, lithium manganese oxide batteries, lithium manganese iron phosphate batteries, or lithium-rich manganese-based batteries.

10. The method for calculating the AC internal resistance of a lithium-ion battery based on physical parameter analysis according to claim 1, characterized in that, Lithium-ion batteries can be cylindrical, pouch, or prismatic.

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