A method and device for simulating and decomposing DC internal resistance of wound battery cells

Abstract

The present application belongs to the technical field of DC internal resistance testing of lithium batteries, and discloses a DC internal resistance simulation decomposition method and device for wound battery cells, which calculates at least two types of electrode external resistances based on the structural size parameters of the wound battery cell; then, obtains the material fluid parameters of the wound battery cell, and simulates and models the material fluid parameters according to a preset electrochemical model to solve and obtain the material physical parameters of the wound battery cell; then, calculates at least two types of electrode internal resistances based on the material physical parameters, and uses all electrode external resistances and all electrode internal resistances as the DC internal resistance decomposition results of the wound battery cell. This not only eliminates the need for battery manufacturing and actual testing, effectively saving production testing resources and costs, but also subdivides the DC internal resistance of the wound battery cell into multiple electrode external resistances and multiple electrode internal resistances, thereby providing beneficial positive guidance for the structural design of the wound battery cell.

Description

Technical Field

[0001] The present application belongs to the technical field of lithium battery DC internal resistance testing, and in particular relates to a method and device for simulating and decomposing the DC internal resistance of wound battery cells. Background Art

[0002] The DC internal resistance of a lithium battery cell is a relatively important electrical performance parameter of the battery cell. When the DC internal resistance of the battery cell is large, in addition to affecting the battery cell power, the excessive Joule heat generated will also cause the internal temperature of the battery cell to rise, thereby affecting the battery cell's lifespan and safety. Therefore, when designing lithium batteries, the DC internal resistance of the battery cell must be reduced as much as possible to improve safety and reliability.

[0003] In order to effectively reduce the DC internal resistance of the battery cell, it is necessary to decompose the components of the DC internal resistance of the battery cell. There are two main methods for decomposing the DC internal resistance of the battery cell. One is to decompose the DC internal resistance of the battery cell into three main components: ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance based on manual experience. This is not only too dependent on manual experience, but also the internal resistance decomposition results are not precise enough. The other is to further decompose the internal resistance results obtained by manufacturing lithium batteries and conducting electrochemical impedance spectroscopy tests. The entire process is completely dependent on actual battery manufacturing and measurement. Not only is the testing and data processing process too cumbersome, time-consuming and labor-intensive, but the internal resistance decomposition results are also not precise enough. Summary of the Invention

[0004] This application aims to address the technical drawbacks of the existing internal resistance decomposition methods mentioned above, which are overly dependent on manual experience on the one hand and completely rely on actual battery production and measurement on the other hand. The testing and data processing processes are too cumbersome, and the internal resistance decomposition results are not precise enough. A DC internal resistance simulation decomposition method and device for wound battery cells are proposed, including:

[0005] In a first aspect, an embodiment of the present application provides a method for simulating and decomposing the DC internal resistance of a wound battery cell, comprising:

[0006] Calculate at least two types of electrode external resistances based on the structural size parameters of the wound cell battery;

[0007] Obtaining the material fluid parameters of the wound cell battery, and performing simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain the material physical parameters of the wound cell battery;

[0008] At least two types of pole piece internal resistances are calculated based on the physical parameters of the material, and all pole piece external resistances and all pole piece internal resistances are used as the DC internal resistance decomposition results of the wound cell battery.

[0009] In an optional solution of the first aspect, the method further comprises:

[0010] When the number of core packs of the wound cell battery reaches a preset number threshold, the internal resistances of all electrode sheets are summed, and the internal equivalent resistance is obtained according to the summation result;

[0011] Calculate the first DC internal resistance of the wound cell battery based on the external resistance of all electrode sheets, the internal equivalent resistance, and the number of tabs of the wound cell battery;

[0012] Using the first DC internal resistance as the DC internal resistance of the wound cell battery; or

[0013] When the number of core packs of the wound cell battery exceeds a preset threshold, a second DC internal resistance of the wound cell battery is calculated based on the first DC internal resistance, the external resistances of all electrode sheets, and the number of core packs of the wound cell battery;

[0014] The second DC internal resistance is used as the DC internal resistance of the wound cell battery.

[0015] In another optional solution of the first aspect, the structural dimension parameters of the wound cell battery include the resistivity of the positive electrode column, the thickness of the positive electrode column, the minimum cross-sectional area of ​​the positive electrode column, the total thickness of the positive electrode connecting piece welding, the positive laser weld print area, the effective length of the positive electrode, the cross-sectional area of ​​the positive electrode connecting piece, the total thickness of the positive electrode ear welding, the total area of ​​the positive electrode weld print, the resistivity of the negative electrode column, the thickness of the negative electrode column, the minimum cross-sectional area of ​​the negative electrode column, the total thickness of the negative electrode connecting piece welding, the negative laser weld print area, the effective length of the negative electrode, the cross-sectional area of ​​the negative electrode connecting piece, the total thickness of the negative electrode ear welding, and the total area of ​​the negative electrode weld print;

[0016] Based on the structural dimension parameters of the wound cell battery, at least two types of electrode external resistance are calculated, including:

[0017] Calculate the positive electrode resistance based on the positive electrode resistivity, thickness and minimum cross-sectional area of ​​the positive electrode.

[0018] The positive electrode laser welding resistance is calculated based on the positive electrode column resistivity, the total thickness of the positive electrode connecting piece welding and the positive laser welding area;

[0019] Calculate the positive electrode connector resistance based on the positive electrode column resistivity, the positive electrode effective length, and the positive electrode connector cross-sectional area;

[0020] The positive electrode ultrasonic weld resistance is calculated based on the positive electrode column resistivity, the total positive electrode ear weld thickness, and the total positive electrode weld area. The positive electrode column resistance, the positive electrode laser weld resistance, the positive electrode connector resistance, and the positive electrode ultrasonic weld resistance are summed to obtain the positive electrode ohmic resistance.

[0021] Calculate the resistance of the negative electrode according to the resistivity, thickness and minimum cross-sectional area of ​​the negative electrode.

[0022] The negative electrode laser welding resistance is calculated based on the negative electrode column resistivity, the total thickness of the negative electrode connecting piece welding and the negative laser welding area;

[0023] Calculate the resistance of the negative electrode connector according to the negative electrode column resistivity, the effective length of the negative electrode, and the cross-sectional area of ​​the negative electrode connector;

[0024] The negative electrode ultrasonic weld resistance is calculated based on the negative electrode column resistivity, the total thickness of the negative electrode ear weld, and the total area of ​​the negative electrode weld mark. The negative electrode column resistance, the negative electrode laser weld resistance, the negative electrode connector resistance, and the negative electrode ultrasonic weld mark resistance are summed to obtain the negative electrode ohmic resistance.

[0025] The positive electrode ohmic resistor and the negative electrode ohmic resistor are used as at least two types of electrode external resistors.

[0026] In another optional solution of the first aspect, the structural dimension parameters of the wound cell battery further include the length of the positive electrode tab welding area, the cross-sectional area of ​​a single positive electrode tab, the length of the negative electrode tab welding area, and the cross-sectional area of ​​a single negative electrode tab;

[0027] The positive electrode ohmic resistor and the negative electrode ohmic resistor are used as at least two types of electrode external resistors, and further include:

[0028] Calculate the resistance of a single positive lug based on the resistivity of the positive column, the length of the positive lug welding area, and the cross-sectional area of ​​a single positive lug;

[0029] Calculate the resistance of a single negative lug based on the resistivity of the negative electrode column, the length of the negative lug welding area, and the cross-sectional area of ​​a single negative lug;

[0030] The positive electrode ohmic resistance, the negative electrode ohmic resistance, the single positive electrode tab resistance and the single negative electrode tab resistance are used as at least two types of electrode external resistances.

[0031] In another optional scheme of the first aspect, the material physical parameters include at least two moments, and at least two positive electrode region liquid potentials, at least two positive electrode region solid phase potentials, the liquid phase potential of the positive electrode-separator interface, at least two positive electrode solid phase lithium concentrations, the positive electrode surface lithium concentration, the positive electrode maximum lithium concentration, current, at least two negative electrode region liquid phase potentials, at least two negative electrode region solid phase potentials, the liquid phase potential of the negative electrode-separator interface, at least two negative electrode solid phase lithium concentrations, the negative electrode surface lithium concentration and the negative electrode maximum lithium concentration corresponding to each moment;

[0032] Calculate at least two types of internal resistance of the electrode based on the physical parameters of the material, including:

[0033] Determine the target time from all the times based on the specified charge and discharge parameters, and average the liquid phase potentials of all the positive electrode regions corresponding to the target time to obtain the average liquid phase potential of the positive electrode region;

[0034] The positive electrode liquid phase concentration polarization resistance is calculated based on the average liquid potential in the positive electrode region, the liquid potential at the positive electrode-diaphragm interface, and the current corresponding to the target time;

[0035] The average value of all positive electrode solid phase lithium concentrations and positive electrode surface lithium concentrations corresponding to the target time is processed to obtain the positive electrode solid phase average lithium concentration, and the positive electrode solid phase concentration polarization resistance is calculated based on the positive electrode solid phase average lithium concentration, the positive electrode surface lithium concentration corresponding to the target time, the positive electrode maximum lithium concentration and the current;

[0036] The solid-phase potentials of all positive electrode regions corresponding to the target time are averaged to obtain the average solid-phase potential of the positive electrode region. The positive electrode charge transfer resistance is calculated based on the average liquid-phase potential of the positive electrode region, the average solid-phase potential of the positive electrode region, the positive electrode surface lithium concentration corresponding to the target time, the maximum lithium concentration of the positive electrode, and the current.

[0037] The positive electrode electrochemical polarization resistance is obtained by summing the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance;

[0038] Performing average processing on the liquid phase potentials of all negative electrode regions corresponding to the target time to obtain the average liquid phase potential of the negative electrode region;

[0039] Calculate the negative electrode liquid concentration polarization resistance based on the average liquid potential in the negative electrode region, the liquid potential at the negative electrode-diaphragm interface, and the current corresponding to the target time;

[0040] The average value of all negative electrode solid phase lithium concentrations and negative electrode surface lithium concentrations corresponding to the target time is processed to obtain the negative electrode solid phase average lithium concentration, and the negative electrode solid phase concentration polarization resistance is calculated based on the negative electrode solid phase average lithium concentration, the negative electrode surface lithium concentration corresponding to the target time, the negative electrode maximum lithium concentration and the current;

[0041] The solid phase potentials of all negative electrode regions corresponding to the target time are averaged to obtain the average solid phase potential of the negative electrode region. The negative electrode charge transfer resistance is calculated based on the average liquid phase potential of the negative electrode region, the average solid phase potential of the negative electrode region, the negative electrode surface lithium concentration corresponding to the target time, the maximum lithium concentration of the negative electrode, the current, and the negative electrode solid electrolyte interface film resistance.

[0042] The negative electrode electrochemical polarization resistance is obtained by summing the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance, and the negative electrode solid electrolyte interface film resistance;

[0043] According to the liquid phase potential of the positive electrode-diaphragm interface, the liquid phase potential of the negative electrode-diaphragm interface and the current corresponding to the target moment, the diaphragm liquid phase concentration polarization resistance is calculated, and the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance and the diaphragm liquid phase concentration polarization resistance are used as at least two types of electrode internal resistances.

[0044] In another optional solution of the first aspect, the material physical parameters further include total polarization overpotential;

[0045] The positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance and the diaphragm liquid phase concentration polarization resistance are used as at least two types of electrode internal resistances, and further include:

[0046] The positive electrode electron transfer resistance and the negative electrode electron transfer resistance are calculated based on the total polarization overpotential, the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the current corresponding to the target time, the conductivity of the positive electrode sheet material, and the conductivity of the negative electrode sheet material.

[0047] The positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance are used as at least two types of electrode internal resistances.

[0048] In yet another alternative of the first aspect, the method further comprises:

[0049] The internal resistance of all electrodes is summed up, and based on the internal resistance of each electrode and the summed result, the corresponding resistance ratio is obtained;

[0050] Based on the proportion of all resistance values, the DC internal resistance analysis results of the wound cell battery are determined.

[0051] In a second aspect, an embodiment of the present application provides a device for simulating and decomposing the DC internal resistance of a wound battery cell, comprising:

[0052] A first decomposition module is used to calculate at least two types of electrode sheet external resistances based on the structural size parameters of the wound cell battery;

[0053] A parameter acquisition module is used to obtain the material fluid parameters of the wound cell battery and simulate and solve the material fluid parameters according to a preset electrochemical model to obtain the material physical parameters of the wound cell battery;

[0054] The second decomposition module is used to calculate at least two types of pole piece internal resistances based on the physical parameters of the material, and use all pole piece external resistances and all pole piece internal resistances as the DC internal resistance decomposition results of the wound cell battery.

[0055] In a third aspect, an embodiment of the present application further provides a device for simulating and decomposing the DC internal resistance of a wound battery cell, comprising a processor and a memory;

[0056] The processor is connected to the memory;

[0057] a memory for storing executable program code;

[0058] The processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory, so as to implement the DC internal resistance simulation decomposition method for wound battery cells provided by the first aspect of the embodiment of the present application or any one of the implementation methods of the first aspect.

[0059] In a fourth aspect, an embodiment of the present application provides a computer storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, the DC internal resistance simulation decomposition method for wound battery cells provided by the first aspect of the embodiment of the present application or any one of the implementation methods of the first aspect can be implemented.

[0060] Beneficial effects of this application:

[0061] When simulating and decomposing the DC internal resistance of a wound cell battery, at least two types of electrode external resistances are calculated based on the structural size parameters of the wound cell battery; then, the material fluid parameters of the wound cell battery are obtained, and the material fluid parameters are simulated and modeled and solved according to a preset electrochemical model to obtain the material physical parameters of the wound cell battery; then, at least two types of electrode internal resistances are calculated based on the material physical parameters, and all electrode external resistances and all electrode internal resistances are used as the DC internal resistance decomposition results of the wound cell battery. This not only eliminates the need for battery manufacturing and actual testing, effectively saving production testing resources and costs, but also subdivides the DC internal resistance of the wound cell battery into multiple electrode external resistances and multiple electrode internal resistances, thereby providing useful positive guidance for the structural design of the wound cell battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0063] Figure 1 This is an overall flow chart of a method for simulating and decomposing the DC internal resistance of a wound battery cell provided in an embodiment of the present application;

[0064] Figure 2A schematic structural diagram of a wound cell battery provided in an embodiment of the present application;

[0065] Figure 3 A schematic diagram of a decomposition equivalent circuit of the DC internal resistance of a wound battery cell provided in an embodiment of the present application;

[0066] Figure 4 A schematic diagram showing the decomposition ratio of the internal resistance of a pole piece of a wound battery cell provided in an embodiment of the present application;

[0067] Figure 5 A schematic structural diagram of a DC internal resistance simulation and decomposition device for wound battery cells provided in an embodiment of the present application;

[0068] Figure 6 A schematic structural diagram of another device for simulating and decomposing the DC internal resistance of a wound battery cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0070] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present application. Different embodiments can be replaced or combined, so the present application can also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, even though the embodiment may not be clearly described in the following text.

[0071] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present application. Various examples may appropriately omit, replace, or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described in some examples may be combined in other examples.

[0072] It should be emphasized that the above-mentioned existing methods of decomposing the DC internal resistance of the battery cell are mainly divided into two types. One is to decompose the DC internal resistance of the battery cell into three main components based on manual experience: ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance. That is, by testing the lithium battery for a preset charge and discharge time, a DC internal resistance sequence is obtained, which is matched with the AC resistance value to obtain the ohmic internal resistance. The DC internal resistance sequence can also be matched with the EIS resistance to obtain the target DC internal resistance, and the target DC internal resistance can be matched with the AC resistance to obtain the electrochemical polarization internal resistance, and the concentration polarization internal resistance under the preset charge and discharge time is obtained by subtracting the DC internal resistance sequence from the target DC internal resistance. This method can directly calculate the ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance by measuring the apparent electrical performance parameters of the battery, but the decomposition result of the DC internal resistance of this battery cell is not detailed enough, and does not involve the corresponding resistance of the components. In the future, it can only rely on manual experience to optimize and improve the DC internal resistance of the battery cell based on the ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance.

[0073] Another method is to make lithium batteries (such as full batteries, half batteries or button batteries) and conduct electrochemical impedance spectroscopy tests to obtain ohmic internal resistance, electrochemical reaction internal resistance and diffusion resistance. Symmetrical batteries can also be made to obtain diaphragm internal resistance and membrane resistance, and then the DC internal resistance of the battery cell can be decomposed into negative electrode mechanical resistance, negative electrode polarization resistance, diaphragm resistance, positive electrode polarization resistance and positive electrode mechanical resistance. However, the internal resistance types decomposed by this method are also not detailed enough. Some internal resistance types have problems such as unclear physical nature or vague concepts. In addition, the entire decomposition process relies entirely on actual battery production measurements, which also makes the testing and data processing process too cumbersome, time-consuming and labor-intensive.

[0074] Based on this, this application will explain the DC internal resistance simulation decomposition method for wound battery cells in combination with one or more embodiments proposed below to solve the above-mentioned technical defects.

[0075] See next Figure 1 , Figure 1 The figure shows an overall flow chart of a DC internal resistance simulation decomposition method for a wound battery cell provided in an embodiment of the present application.

[0076] like Figure 1 As shown, the DC internal resistance simulation decomposition method for wound battery cells may include at least the following steps:

[0077] Step 102: Calculate at least two types of electrode sheet external resistances based on the structural dimension parameters of the wound cell battery.

[0078] In the embodiment of the present application, the DC internal resistance simulation decomposition method for wound cell can be applied to, but is not limited to, a control terminal, which can obtain the parameters used by the user when designing a wound cell battery, and analyze and process the parameters to obtain multiple types of resistance decomposed from the DC internal resistance of the wound cell battery, so that the user can improve the designed wound cell battery by combining the multiple types of resistance decomposed, thereby achieving the purpose of reducing the DC internal resistance of the wound cell battery. It is understandable that reference can be made here. Figure 2 The structure diagram of a wound cell battery provided by an embodiment of the present application is shown in FIG. Figure 2 As shown, the wound cell battery may include a positive electrode post, a positive connecting piece, a negative electrode post, a negative connecting piece, a winding core and an aluminum shell. The winding core may be composed of a positive electrode, a negative electrode and a separator combined together in a specified winding manner.

[0079] Among them, the parameters used by the user in designing the wound cell battery can be combined with the composition structure of the wound cell battery and divided into structural size parameters and material fluid parameters. The structural size parameters can be but are not limited to including the positive electrode column resistivity, positive electrode column thickness, positive electrode column minimum cross-sectional area, positive electrode connector welding total thickness, positive laser welding area, positive electrode effective length, positive electrode connector cross-sectional area, positive electrode ear welding total thickness, positive electrode welding total area, negative electrode column resistivity, negative electrode column thickness, negative electrode column minimum cross-sectional area, negative electrode connector welding total thickness, negative laser welding area, negative electrode effective length, negative electrode connector cross-sectional area, negative ear welding The total thickness, the total area of ​​the negative electrode weld mark, the length of the positive electrode ear welding area, the cross-sectional area of ​​a single positive electrode ear, the length of the negative electrode ear welding area and the cross-sectional area of ​​a single negative electrode ear, etc. The material fluid parameters may include but are not limited to the thickness, particle size, solid phase volume fraction, liquid phase volume fraction, exchange current density, solid phase diffusion coefficient, density, gram capacity, electrolyte solubility, transfer coefficient, transfer coefficient correction coefficient and temperature corresponding to different component structures of the wound battery cell (such as positive electrode sheet, negative electrode sheet and separator), and the structural size parameters and material fluid parameters can be designed by the user and obtained by actual testing, but they are not elaborated here.

[0080] Here, the various types of resistance decomposed from the DC internal resistance of the wound cell battery can be divided into a variety of electrode external resistances and a variety of electrode internal resistances as a whole. The various electrode external resistances may include but are not limited to the positive electrode ohmic resistance (which can be further divided into positive electrode column resistance, positive electrode laser welding resistance, positive electrode connecting piece resistance and positive electrode ultrasonic welding resistance), the negative electrode ohmic resistance (which can be further divided into negative electrode column resistance, negative electrode laser welding resistance, negative electrode connecting piece resistance and negative electrode ultrasonic welding resistance), a single positive ear resistance (also known as the positive ear resistance) and a single Negative electrode ear resistance (also known as negative electrode ear resistance), the various internal resistances of the electrode sheets may include but are not limited to the positive electrode electrochemical polarization resistance (which can be further subdivided into the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance), the negative electrode electrochemical polarization resistance (which can be further subdivided into the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance and the negative electrode solid electrolyte interface membrane resistance), the diaphragm liquid phase concentration polarization resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance, and are not limited to this.

[0081] It can be understood that the control terminal calculates at least two types of electrode external resistances based on the structural size parameters of the wound cell battery; then, the material fluid parameters of the wound cell battery are obtained, and the material fluid parameters are simulated and modeled according to a preset electrochemical model to solve the material physical parameters of the wound cell battery; then, at least two types of electrode internal resistances are calculated based on the material physical parameters, and all electrode external resistances and all electrode internal resistances are used as the DC internal resistance decomposition results of the wound cell battery. Not only does it eliminate the need to manufacture batteries and actual tests, effectively saving production testing resources and costs, but it can also subdivide the DC internal resistance of the wound cell battery into multiple electrode external resistances and multiple electrode internal resistances, thereby providing useful positive guidance for the structural design of the wound cell battery.

[0082] Specifically, when simulating and decomposing the DC internal resistance of a wound cell battery, the control terminal can, but is not limited to, obtaining the structural dimension parameters used by the user when designing the wound cell battery, so as to calculate a plurality of electrode external resistances based on the structural dimension parameters and a preset resistance calculation formula. The plurality of electrode external resistances may include any at least two of the above-mentioned positive electrode ohmic resistance, negative electrode ohmic resistance, single positive electrode ear resistance, and single negative electrode ear resistance.

[0083] As an optional embodiment of the present application, the structural size parameters of the wound cell battery include the resistivity of the positive electrode column, the thickness of the positive electrode column, the minimum cross-sectional area of ​​the positive electrode column, the total thickness of the positive electrode connecting piece welding, the positive laser welding print area, the positive electrode effective length, the cross-sectional area of ​​the positive electrode connecting piece, the total thickness of the positive electrode ear welding, the total area of ​​the positive electrode welding print, the resistivity of the negative electrode column, the thickness of the negative electrode column, the minimum cross-sectional area of ​​the negative electrode column, the total thickness of the negative electrode connecting piece welding, the negative laser welding print area, the negative electrode effective length, the cross-sectional area of ​​the negative electrode connecting piece, the total thickness of the negative electrode ear welding and the total area of ​​the negative electrode welding print;

[0084] Based on the structural dimension parameters of the wound cell battery, at least two types of electrode external resistance are calculated, including:

[0085] Calculate the positive electrode resistance based on the positive electrode resistivity, thickness and minimum cross-sectional area of ​​the positive electrode.

[0086] The positive electrode laser welding resistance is calculated based on the positive electrode column resistivity, the total thickness of the positive electrode connecting piece welding and the positive laser welding area;

[0087] Calculate the positive electrode connector resistance based on the positive electrode column resistivity, the positive electrode effective length, and the positive electrode connector cross-sectional area;

[0088] The positive electrode ultrasonic weld resistance is calculated based on the positive electrode column resistivity, the total positive electrode ear weld thickness, and the total positive electrode weld area. The positive electrode column resistance, the positive electrode laser weld resistance, the positive electrode connector resistance, and the positive electrode ultrasonic weld resistance are summed to obtain the positive electrode ohmic resistance.

[0089] Calculate the resistance of the negative electrode according to the resistivity, thickness and minimum cross-sectional area of ​​the negative electrode.

[0090] The negative electrode laser welding resistance is calculated based on the negative electrode column resistivity, the total thickness of the negative electrode connecting piece welding and the negative laser welding area;

[0091] Calculate the resistance of the negative electrode connector according to the negative electrode column resistivity, the effective length of the negative electrode, and the cross-sectional area of ​​the negative electrode connector;

[0092] The negative electrode ultrasonic weld resistance is calculated based on the negative electrode column resistivity, the total thickness of the negative electrode ear weld, and the total area of ​​the negative electrode weld mark. The negative electrode column resistance, the negative electrode laser weld resistance, the negative electrode connector resistance, and the negative electrode ultrasonic weld mark resistance are summed to obtain the negative electrode ohmic resistance.

[0093] The positive electrode ohmic resistor and the negative electrode ohmic resistor are used as at least two types of electrode external resistors.

[0094] Specifically, when calculating the external resistance of multiple electrode pieces, the control terminal can substitute the positive electrode column resistivity, the positive electrode column thickness, and the minimum cross-sectional area of ​​the positive electrode column into a preset electrode column resistance calculation formula to calculate the positive electrode column resistance. Here, the preset electrode column resistance calculation formula can be, but is not limited to, the following:

[0095]

[0096] In the above formula, R 1-1 It can be the positive electrode column resistance, ρ1 can be the positive electrode column resistivity (that is, the resistivity of the positive electrode connecting piece and the positive electrode ear), L1 can be the positive electrode column thickness, and S1 can be the minimum cross-sectional area of ​​the positive electrode column.

[0097] Next, the control terminal may also substitute the positive electrode column resistivity, the total thickness of the positive electrode connecting piece weld, and the positive laser weld area into a preset laser welding resistance calculation formula to calculate the positive electrode laser welding resistance. Here, the preset laser welding resistance calculation formula may be, but is not limited to, the following:

[0098]

[0099] In the above formula, R 1-2 It can be the positive electrode laser welding resistance, ρ1 can be the positive electrode column resistivity, L2 can be the total welding thickness of the positive electrode connecting piece, and S2 can be the positive laser welding print area.

[0100] Next, the control terminal may also substitute the positive electrode column resistivity, the positive electrode effective length, and the positive electrode connecting piece cross-sectional area into a preset connecting piece calculation formula to calculate the positive electrode connecting piece resistance. Here, the preset connecting piece calculation formula may be, but is not limited to, the following:

[0101]

[0102] In the above formula, R 1-3 It can be the positive electrode connecting piece resistance, ρ1 can be the positive electrode column resistivity, L3 can be the positive electrode effective length, and S3 can be the positive electrode connecting piece cross-sectional area.

[0103] Here, the effective length of the positive electrode can be understood as the effective length of the positive electrode connection in the direction of current transmission. For example, taking the connecting piece as a thin plate of 100mm*60mm*2mm, with a 20mm diameter laser welding area and a 5mm*10mm square ultrasonic welding area at both ends as an example, the effective length of the positive electrode is the distance between the two welding areas, that is, the current transmission path, which is equal to or less than 70mm, and is not limited to this.

[0104] Next, the control terminal may also substitute the positive electrode column resistivity, the total positive electrode tab weld thickness, and the total positive electrode weld area into a preset ultrasonic weld resistance calculation formula to calculate the positive electrode ultrasonic weld resistance. Here, the preset ultrasonic weld resistance calculation formula may be, but is not limited to, the following:

[0105]

[0106] In the above formula, R 1-4 It can be the positive electrode ultrasonic weld resistance, ρ1 can be the positive electrode column resistivity, L4 can be the total welding thickness of the positive electrode ear (that is, the total thickness of the positive electrode ear after ultrasonic welding), and S4 can be the total positive electrode weld area.

[0107] Next, the control terminal may sum the positive electrode column resistance, the positive electrode laser welding resistance, the positive electrode connecting sheet resistance, and the positive electrode ultrasonic welding resistance to obtain the positive electrode ohmic resistance. It is understood that when the control terminal uses the positive electrode ohmic resistance as a type of electrode sheet external resistance, it may also, but is not limited to, use the aforementioned positive electrode column resistance, positive electrode laser welding resistance, positive electrode connecting sheet resistance, and positive electrode ultrasonic welding resistance as multiple electrode sheet external resistances, and is not limited thereto.

[0108] Of course, when calculating the external resistance of multiple electrode pieces, the control terminal can also substitute the negative electrode column resistivity, negative electrode column thickness, and negative electrode column minimum cross-sectional area into the preset electrode column resistance calculation formula to calculate the negative electrode column resistance. Here, the preset electrode column resistance calculation formula can be, but is not limited to, the following:

[0109]

[0110] In the above formula, R 2-1 It can be the resistance of the negative electrode column, ρ2 can be the resistivity of the negative electrode column, L5 can be the thickness of the negative electrode column, and S5 can be the minimum cross-sectional area of ​​the negative electrode column.

[0111] Next, the control terminal may also substitute the negative electrode column resistivity, the total thickness of the negative electrode connecting piece weld, and the negative laser weld area into a preset laser welding resistance calculation formula to calculate the negative electrode laser welding resistance. Here, the preset laser welding resistance calculation formula may be, but is not limited to, the following:

[0112]

[0113] In the above formula, R 2-2 It can be the negative electrode laser welding resistance, ρ2 can be the negative electrode column resistivity, L6 can be the total welding thickness of the negative electrode connecting piece, and S6 can be the negative laser welding area.

[0114] Next, the control terminal may also substitute the negative electrode column resistivity, the negative electrode effective length, and the negative electrode connecting piece cross-sectional area into a preset connecting piece calculation formula to calculate the negative electrode connecting piece resistance. Here, the preset connecting piece calculation formula may be, but is not limited to, the following:

[0115]

[0116] In the above formula, R 2-3 It can be the resistance of the negative electrode connecting piece, ρ2 can be the resistivity of the negative electrode column, L7 can be the effective length of the negative electrode (refer to the explanation of the effective length of the positive electrode mentioned above), and S7 can be the cross-sectional area of ​​the negative electrode connecting piece.

[0117] Next, the control terminal may also substitute the negative electrode column resistivity, the total thickness of the negative electrode tab weld, and the total area of ​​the negative electrode weld mark into a preset ultrasonic weld mark resistance calculation formula to calculate the negative electrode ultrasonic weld mark resistance. Here, the preset ultrasonic weld mark resistance calculation formula may be, but is not limited to, the following:

[0118]

[0119] In the above formula, R 2-4 It can be the negative electrode ultrasonic weld resistance, ρ2 can be the negative electrode column resistivity, L8 can be the total thickness of the negative electrode ear weld, and S8 can be the total area of ​​the negative electrode weld.

[0120] Next, the control terminal may sum the negative electrode post resistance, the negative electrode laser welding resistance, the negative electrode connecting sheet resistance, and the negative electrode ultrasonic welding resistance to obtain the negative electrode ohmic resistance. It is understood that the control terminal may use the negative electrode ohmic resistance as a type of electrode sheet external resistance, and may also use, but is not limited to, the aforementioned negative electrode post resistance, negative electrode laser welding resistance, negative electrode connecting sheet resistance, and negative electrode ultrasonic welding resistance as multiple electrode sheet external resistances.

[0121] As another option in the embodiment of the present application, the structural dimension parameters of the wound cell battery further include the length of the positive electrode tab welding area, the cross-sectional area of ​​a single positive electrode tab, the length of the negative electrode tab welding area, and the cross-sectional area of ​​a single negative electrode tab;

[0122] The positive electrode ohmic resistor and the negative electrode ohmic resistor are used as at least two types of electrode external resistors, and further include:

[0123] Calculate the resistance of a single positive lug based on the resistivity of the positive column, the length of the positive lug welding area, and the cross-sectional area of ​​a single positive lug;

[0124] Calculate the resistance of a single negative lug based on the resistivity of the negative electrode column, the length of the negative lug welding area, and the cross-sectional area of ​​a single negative lug;

[0125] The positive electrode ohmic resistance, the negative electrode ohmic resistance, the single positive electrode tab resistance and the single negative electrode tab resistance are used as at least two types of electrode external resistances.

[0126] Specifically, when determining the external resistance of multiple electrode pieces, the control terminal may also substitute the positive electrode column resistivity, the positive electrode tab welding area length, and the cross-sectional area of ​​a single positive electrode tab into a preset tab resistance calculation formula to calculate the resistance of a single positive electrode tab. Here, the preset tab resistance calculation formula may be, but is not limited to, the following:

[0127]

[0128] In the above formula, R3 can be the resistance of a single positive ear, ρ1 can be the resistivity of the positive electrode column, L9 can be the length of the positive ear welding area (that is, the length from the positive ear ultrasonic welding area to the die-cut edge), and S9 can be the cross-sectional area of ​​a single positive ear.

[0129] Next, the control terminal may also substitute the negative electrode column resistivity, the negative electrode tab welding area length, and the cross-sectional area of ​​a single negative electrode tab into a preset tab resistance calculation formula to calculate the single negative electrode tab resistance. Here, the preset tab resistance calculation formula may be, but is not limited to, the following:

[0130]

[0131] In the above formula, R4 can be the resistance of a single negative ear, ρ2 can be the resistivity of the negative column, L 10 It can be the length of the negative electrode ear welding area (that is, the length from the negative electrode ear ultrasonic welding area to the die-cut edge), S 10 It can be the cross-sectional area of ​​a single negative electrode ear.

[0132] It is understandable that the control terminal can also use a single positive ear resistor, a single negative ear resistor, and the above-mentioned positive electrode ohmic resistor (or subdivided into positive electrode column resistor, positive electrode laser welding resistor, positive electrode connecting piece resistor and positive electrode ultrasonic welding resistor) and negative electrode ohmic resistor (or subdivided into negative electrode column resistor, negative electrode laser welding resistor, negative electrode connecting piece resistor and negative electrode ultrasonic welding resistor) as multiple electrode external resistors.

[0133] Step 104 : Obtain material fluid parameters of the wound cell battery, and perform simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain material physical parameters of the wound cell battery.

[0134] Specifically, when simulating and decomposing the DC internal resistance of the wound cell battery, the control terminal can also, but is not limited to, obtain the material fluid parameters used by the user in designing the wound cell battery. The material fluid parameters can be understood as a variety of parameters required to construct a simulation model of the wound cell battery, which can include but are not limited to the thickness, particle size, solid phase volume fraction, liquid phase volume fraction, exchange current density, solid phase diffusion coefficient, density, gram capacity, electrolyte solubility, transfer coefficient, transfer coefficient correction coefficient and temperature corresponding to different component structures of the wound cell battery (such as positive electrode sheet, negative electrode sheet and diaphragm), and the material fluid parameters can be obtained by user design and conventional testing methods, but will not be elaborated here.

[0135] Furthermore, after obtaining the material fluid parameters, the control terminal can substitute the material fluid parameters and specified charge and discharge parameters (for example, may include specified charge and discharge current rates and specified charge and discharge times) into a preset electrochemical model to construct a geometric simulation model of the wound cell battery under the specified charge and discharge parameters, and perform numerical solution processing on the geometric simulation model through a preset finite element solution algorithm to obtain the material physical parameters of the wound cell battery under the specified charge and discharge parameters.

[0136] Here, since the DC internal resistance of the wound cell battery decomposes the internal resistance of the various electrodes and is negatively correlated with the area of ​​the battery electrode, the above-mentioned preset electrochemical model can be a pseudo-two-dimensional electrochemical model well known in the art, that is, the wound cell battery is simplified into multiple one-dimensional geometric simulation models and pseudo-dimensional geometric simulation models along the electrode thickness direction and the particle size direction. The geometric simulation model is divided into negative electrode fluid, negative electrode material, diaphragm, positive electrode material and positive current collector areas. By inputting the area of ​​a layer of positive electrode sheet as the effective area, an additional dimension is established inside the positive electrode active material and negative electrode active material particles to solve the lithium ion diffusion coefficient inside the solid particles.

[0137] It is understandable that the preset electrochemical model can use partial differential equations and algebraic equations to describe the transient changes of all physical quantities at each location in space under a specified working load. The partial differential equations may include the lithium ion solid phase diffusion equation (extra dimension), the lithium ion solid phase potential distribution equation, the lithium ion liquid phase ion distribution equation, the lithium ion liquid phase potential distribution equation, and the solid-liquid interface electrochemical reaction equation, wherein the lithium ion solid phase diffusion equation can be, but is not limited to, expressed using Fick's second law:

[0138]

[0139] The lithium ion liquid phase ion distribution equation can be expressed, but is not limited to, using the diffusion and migration conservation equations based on concentrated solution theory:

[0140]

[0141] The lithium ion liquid phase potential distribution equation can be expressed, but is not limited to, using the liquid phase charge conservation equation:

[0142]

[0143] The lithium ion solid phase potential distribution equation can be expressed by, but is not limited to, Ohm's equation:

[0144]

[0145] The electrochemical reaction equation at the solid-liquid interface can be expressed by, but is not limited to, the Butler-Volmer equation:

[0146]

[0147] In the above mentioned equations, c s Can be the solid phase ion concentration, c l can be the liquid phase ion concentration, t can be the time, r can be the radius of the active material (ie, particle size), D s can be the solid phase diffusion coefficient, Can be the effective diffusion coefficient of the liquid phase, j n Can be the local current density, i s Can be the solid phase current density, i l can be the liquid phase current density, It can be the solid phase effective conductivity, Can be the effective conductivity of the liquid phase, φ s Can be the solid phase potential, φ l can be the liquid phase potential, η can be the overpotential, U e can be the equilibrium potential, I can be the current, T can be the battery temperature, t + Can be the ion transfer coefficient, f ± Can be the activity correlation coefficient, ε l can be the liquid volume fraction, i0 can be the exchange current density, α a Can be the reaction transfer coefficient of the oxidation reaction, α c may be the reaction transfer coefficient of the reduction reaction, F may be the Faraday constant, R may be the Boltzmann constant, It can be understood as a gradient operator (i.e., representing the derivative of spatial coordinates). It should be noted that the above-mentioned method of simulating and modeling the wound cell battery based on the preset electrochemical model can also refer to the technical means known in the art, which will not be elaborated here.

[0148] It can also be understood that the material physical parameters of the wound cell battery under specified charge and discharge parameters can be understood as the solid phase potential, current and lithium ion concentration in the thickness direction of each sampling point in the corresponding geometric simulation model space at each charge and discharge moment, and the liquid phase potential, current and lithium ion concentration in the direction inside the particle size of each sampling point, such as but not limited to at least two moments, and at least two positive electrode region liquid phase potentials, at least two positive electrode region solid phase potentials, liquid phase potential of the positive electrode-diaphragm interface, at least two positive electrode solid phase lithium concentrations, positive electrode surface lithium concentration, current, at least two negative electrode region liquid phase potentials, at least two negative electrode region solid phase potentials, liquid phase potential of the negative electrode-diaphragm interface, at least two negative electrode solid phase lithium concentrations and negative electrode surface lithium concentration corresponding to each moment.

[0149] Step 106: Calculate at least two types of electrode internal resistances based on the physical parameters of the materials, and use all electrode external resistances and all electrode internal resistances as the DC internal resistance decomposition result of the wound cell battery.

[0150] Specifically, after obtaining the material parameters of the wound cell battery under specified charge and discharge parameters, the control terminal can, but is not limited to, calculate multiple electrode internal resistances based on the resistance calculation formula of the material physical parameters and factors. The multiple electrode internal resistances may include any at least two of the above-mentioned positive electrode electrochemical polarization resistance, negative electrode electrochemical polarization resistance, diaphragm liquid phase concentration polarization resistance, positive electrode electron transfer resistance and negative electrode electron transfer resistance, and all calculated electrode external resistances and all electrode internal resistances can be used together as the DC internal resistance decomposition result of the wound cell battery.

[0151] As another optional embodiment of the present application, the material physical parameters include at least two moments, and at least two positive electrode region liquid potentials, at least two positive electrode region solid phase potentials, the liquid phase potential of the positive electrode-diaphragm interface, at least two positive electrode solid phase lithium concentrations, the positive electrode surface lithium concentration, the positive electrode maximum lithium concentration, current, at least two negative electrode region liquid phase potentials, at least two negative electrode region solid phase potentials, the liquid phase potential of the negative electrode-diaphragm interface, at least two negative electrode solid phase lithium concentrations, the negative electrode surface lithium concentration and the negative electrode maximum lithium concentration corresponding to each moment;

[0152] Calculate at least two types of internal resistance of the electrode based on the physical parameters of the material, including:

[0153] Determine the target time from all the times based on the specified charge and discharge parameters, and average the liquid phase potentials of all the positive electrode regions corresponding to the target time to obtain the average liquid phase potential of the positive electrode region;

[0154] The positive electrode liquid phase concentration polarization resistance is calculated based on the average liquid potential in the positive electrode region, the liquid potential at the positive electrode-diaphragm interface, and the current corresponding to the target time;

[0155] The average value of all positive electrode solid phase lithium concentrations and positive electrode surface lithium concentrations corresponding to the target time is processed to obtain the positive electrode solid phase average lithium concentration, and the positive electrode solid phase concentration polarization resistance is calculated based on the positive electrode solid phase average lithium concentration, the positive electrode surface lithium concentration corresponding to the target time, the positive electrode maximum lithium concentration and the current;

[0156] The solid-phase potentials of all positive electrode regions corresponding to the target time are averaged to obtain the average solid-phase potential of the positive electrode region. The positive electrode charge transfer resistance is calculated based on the average liquid-phase potential of the positive electrode region, the average solid-phase potential of the positive electrode region, the positive electrode surface lithium concentration corresponding to the target time, the maximum lithium concentration of the positive electrode, and the current.

[0157] The positive electrode electrochemical polarization resistance is obtained by summing the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance;

[0158] Performing average processing on the liquid phase potentials of all negative electrode regions corresponding to the target time to obtain the average liquid phase potential of the negative electrode region;

[0159] Calculate the negative electrode liquid concentration polarization resistance based on the average liquid potential in the negative electrode region, the liquid potential at the negative electrode-diaphragm interface, and the current corresponding to the target time;

[0160] The average value of all negative electrode solid phase lithium concentrations and negative electrode surface lithium concentrations corresponding to the target time is processed to obtain the negative electrode solid phase average lithium concentration, and the negative electrode solid phase concentration polarization resistance is calculated based on the negative electrode solid phase average lithium concentration, the negative electrode surface lithium concentration corresponding to the target time, the negative electrode maximum lithium concentration and the current;

[0161] The solid phase potentials of all negative electrode regions corresponding to the target time are averaged to obtain the average solid phase potential of the negative electrode region. The negative electrode charge transfer resistance is calculated based on the average liquid phase potential of the negative electrode region, the average solid phase potential of the negative electrode region, the negative electrode surface lithium concentration corresponding to the target time, the maximum lithium concentration of the negative electrode, the current, and the negative electrode solid electrolyte interface film resistance.

[0162] The negative electrode electrochemical polarization resistance is obtained by summing the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance, and the negative electrode solid electrolyte interface film resistance;

[0163] According to the liquid phase potential of the positive electrode-diaphragm interface, the liquid phase potential of the negative electrode-diaphragm interface and the current corresponding to the target moment, the diaphragm liquid phase concentration polarization resistance is calculated, and the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance and the diaphragm liquid phase concentration polarization resistance are used as at least two types of electrode internal resistances.

[0164] Specifically, when calculating the internal resistance of multiple electrode sheets, the control terminal can determine the target time among all the times according to the charge and discharge time in the specified charge and discharge parameters, that is, the time when the wound cell battery is at the end of the charge and discharge, and can perform average processing on the liquid phase potentials of all the positive electrode regions corresponding to the target time to obtain the average liquid phase potential of the positive electrode region, and substitute the average liquid phase potential of the positive electrode region, the liquid phase potential of the positive electrode-diaphragm interface, and the current corresponding to the target time into the preset positive electrode liquid phase concentration polarization resistance formula, thereby calculating the positive electrode liquid phase concentration polarization resistance. Here, the preset positive electrode liquid phase concentration polarization resistance formula can be, but is not limited to, as follows:

[0165]

[0166] In the above formula, R 7-1 It can be the positive electrode liquid phase concentration polarization resistance, It can be the average liquid potential in the positive electrode region, It can be the liquid phase potential of the positive electrode-separator interface, and i can be the current corresponding to the target time.

[0167] Then, the control terminal can also perform average processing on all positive electrode solid phase lithium concentrations and positive electrode surface lithium concentrations (i.e., positive electrode solid phase surface lithium concentrations) corresponding to the target time to obtain the positive electrode solid phase average lithium concentration, and substitute the positive electrode solid phase average lithium concentration, the positive electrode surface lithium concentration corresponding to the target time, the positive electrode maximum lithium concentration, and the current into the preset positive electrode solid phase concentration polarization resistance formula to calculate the positive electrode solid phase concentration polarization resistance. Here, the preset positive electrode solid phase concentration polarization resistance formula can be, but is not limited to, as follows:

[0168]

[0169] In the above formula, R 7-2 Can be the positive electrode solid phase concentration polarization resistance, It can be a positive electrode equilibrium potential curve function (which can be obtained by calculating the positive electrode equilibrium potential during the numerical solution of the above simulation modeling). It can be the average lithium concentration of the positive electrode solid phase, Can be the maximum lithium concentration of the positive electrode, It can be the lithium concentration on the positive electrode surface corresponding to the target time, and i can be the current corresponding to the target time.

[0170] Next, the control terminal may also perform average processing on the solid phase potentials of all positive electrode regions corresponding to the target time to obtain the average solid phase potential of the positive electrode region, and substitute the average liquid phase potential of the positive electrode region, the average solid phase potential of the positive electrode region, the positive electrode surface lithium concentration corresponding to the target time, the maximum positive electrode lithium concentration, and the current into the preset positive electrode charge transfer resistance formula to calculate the positive electrode charge transfer resistance. Here, the preset positive electrode charge transfer resistance formula may be, but is not limited to, the following:

[0171]

[0172] In the above formula, R 7-3 Can be the positive charge transfer resistor, It can be a function of the positive electrode equilibrium potential curve, It can be the lithium concentration on the positive electrode surface corresponding to the target time, Can be the maximum lithium concentration of the positive electrode, It can be the average solid phase potential in the positive electrode region, It can be the average liquid potential of the positive electrode region, and i can be the current corresponding to the target moment.

[0173] Next, the control terminal may sum the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance, and the positive electrode charge transfer resistance to obtain the positive electrode electrochemical polarization resistance. It is understood that when the control terminal uses the positive electrode electrochemical polarization resistance as a type of electrode internal resistance, it may also, but is not limited to, using the above-mentioned positive electrode liquid phase concentration polarization resistance, positive electrode solid phase concentration polarization resistance, and positive electrode charge transfer resistance as multiple electrode internal resistances, and is not limited to this.

[0174] Next, the control terminal may also average the liquid potentials of all negative electrode regions corresponding to the target time to obtain the average liquid potential of the negative electrode region, and substitute the average liquid potential of the negative electrode region, the liquid potential of the negative electrode-diaphragm interface, and the current corresponding to the target time into the preset negative electrode liquid phase concentration polarization resistance formula to calculate the negative electrode liquid phase concentration polarization resistance. Here, the preset negative electrode liquid phase concentration polarization resistance formula may be, but is not limited to, the following:

[0175]

[0176] In the above formula, R 8-1 Can be the negative electrode liquid phase concentration polarization resistance, It can be the average liquid potential in the negative electrode region, It can be the liquid phase potential of the negative electrode-separator interface, and i can be the current corresponding to the target time.

[0177] Then, the control terminal can also perform average processing on all negative electrode solid phase lithium concentrations and negative electrode surface lithium concentrations (i.e., negative electrode solid phase surface lithium concentrations) corresponding to the target time to obtain the negative electrode solid phase average lithium concentration, and substitute the negative electrode solid phase average lithium concentration, the negative electrode surface lithium concentration corresponding to the target time, the negative electrode maximum lithium concentration, and the current into the preset negative electrode solid phase concentration polarization resistance formula to calculate the negative electrode solid phase concentration polarization resistance. Here, the preset negative electrode solid phase concentration polarization resistance formula can be, but is not limited to, the following:

[0178]

[0179] In the above formula, R 8-2 Can be the negative electrode solid phase concentration polarization resistance, It can be the negative electrode equilibrium potential curve function (which can be obtained by calculating the negative electrode equilibrium potential during the numerical solution of the above simulation modeling). It can be the average lithium concentration of the negative electrode solid phase, Can be the maximum lithium concentration of the negative electrode, It can be the lithium concentration on the surface of the negative electrode corresponding to the target time, and i can be the current corresponding to the target time.

[0180] Next, the control terminal may also perform an average processing on the solid phase potentials of all negative electrode regions corresponding to the target time to obtain the average solid phase potential of the negative electrode region, and substitute the average liquid phase potential of the negative electrode region, the average solid phase potential of the negative electrode region, the negative electrode surface lithium concentration corresponding to the target time, the maximum lithium concentration of the negative electrode, the current, and the negative electrode solid electrolyte interface film resistance into the preset negative electrode charge transfer resistance formula to calculate the negative electrode charge transfer resistance. Here, the preset negative electrode charge transfer resistance formula may be, but is not limited to, the following:

[0181]

[0182] In the above formula, R 8-3 Can be the negative electrode charge transfer resistor, Can be the negative electrode equilibrium potential curve function, It can be the lithium concentration on the negative electrode surface corresponding to the target time, Can be the maximum lithium concentration of the negative electrode, It can be the average solid phase potential of the negative electrode region, It can be the average liquid potential in the negative electrode region, R sei，n It can be the resistance of the negative electrode solid electrolyte interface film (which can be obtained according to the numerical solution of the simulation modeling mentioned above, or obtained through conventional testing means), and i can be the current corresponding to the target moment.

[0183] Next, the control terminal may sum the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance, and the negative electrode solid electrolyte interface film resistance to obtain the negative electrode electrochemical polarization resistance. It is understood that when the control terminal uses the negative electrode electrochemical polarization resistance as a type of electrode internal resistance, it may also, but is not limited to, using the above-mentioned negative electrode liquid phase concentration polarization resistance, negative electrode solid phase concentration polarization resistance, and negative electrode charge transfer resistance as multiple electrode internal resistances, and is not limited to this.

[0184] It should be noted that, since the negative electrode material of the wound cell battery is generally artificial graphite, a solid electrolyte interface film is generated by the reaction of the solvent with lithium at a low potential to protect the solvent from further reaction. Therefore, the resistance of the negative electrode solid electrolyte interface film needs to be taken into account when calculating the negative electrode charge transfer resistance and the negative electrode electrochemical polarization resistance. On the other hand, the positive electrode materials of the wound cell battery are divided into many types, such as ternary materials nickel cobalt manganese, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate or lithium manganese iron phosphate. Taking the positive electrode material applied to the embodiment of the present application as lithium iron phosphate as an example, when the voltage is within the electrolyte safety window, the electrolyte will not oxidize, and at the same time, weak side reactions such as oxidative decomposition of the electrolyte lithium salt and deposition of impurity metals may also occur at the positive electrode, that is, forming a solid electrolyte interface film, but usually the thickness of this solid electrolyte interface film is thin, and the composition is complex and the resistance is small, so the solid electrolyte interface film generated by the positive electrode is ignored by default.

[0185] Next, the control terminal can also substitute the liquid phase potential of the positive electrode-diaphragm interface, the liquid phase potential of the negative electrode-diaphragm interface, and the current corresponding to the target time into the preset diaphragm liquid phase concentration polarization resistance formula to calculate the diaphragm liquid phase concentration polarization resistance, and the diaphragm liquid phase concentration polarization resistance can be used as a kind of electrode internal resistance. Here, the preset diaphragm liquid phase concentration polarization resistance formula can be, but is not limited to, the following:

[0186]

[0187] In the above formula, R9 can be the concentration polarization resistance of the diaphragm liquid phase, It can be the liquid phase potential of the negative electrode-separator interface, It can be the liquid phase potential of the positive electrode-separator interface, and i can be the current corresponding to the target time.

[0188] As another option in the embodiment of the present application, the material physical parameters further include a total polarization overpotential;

[0189] The positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance and the diaphragm liquid phase concentration polarization resistance are used as at least two types of electrode internal resistances, and further include:

[0190] The positive electrode electron transfer resistance and the negative electrode electron transfer resistance are calculated based on the total polarization overpotential, the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the current corresponding to the target time, the conductivity of the positive electrode sheet material, and the conductivity of the negative electrode sheet material.

[0191] The positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance are used as at least two types of electrode internal resistances.

[0192] Specifically, when calculating the internal resistance of multiple electrode sheets, the control terminal can also substitute the total polarization overpotential, the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the current corresponding to the target time, the conductivity of the positive electrode sheet material, and the conductivity of the negative electrode sheet material into the preset transfer resistance formula to calculate the positive electrode electron transfer resistance and the negative electrode electron transfer resistance respectively. Here, the positive electrode electron transfer resistance can be obtained by referring to, but is not limited to, the following preset transfer resistance formula:

[0193]

[0194] In the above formula, R5 can be the positive electrode electron transfer resistance, η tot can be the total polarization overpotential, R7 can be the positive electrode electrochemical polarization resistance, R8 can be the negative electrode electrochemical polarization resistance, R9 can be the diaphragm liquid phase concentration polarization resistance, σ pos It can be the conductivity of the positive electrode material (obtained by conventional testing means), σ neg It can be the conductivity of the negative electrode material (obtained by conventional testing means), and i can be the current corresponding to the target moment.

[0195] Here, the negative electrode electron transfer resistance can be obtained by referring to, but not limited to, the following preset transfer resistance formula:

[0196]

[0197] In the above formula, R6 can be the negative electrode electron transfer resistance, η tot can be the total polarization overpotential, R7 can be the positive electrode electrochemical polarization resistance, R8 can be the negative electrode electrochemical polarization resistance, R9 can be the diaphragm liquid phase concentration polarization resistance, σ pos It can be the conductivity of the positive electrode material (obtained by conventional testing means), σ neg It can be the conductivity of the negative electrode material (obtained by conventional testing means), and i can be the current corresponding to the target moment.

[0198] Then, the control terminal can use the positive electrode electron transfer resistance, the negative electrode electron transfer resistance, and the above-mentioned positive electrode electrochemical polarization resistance, negative electrode electrochemical polarization resistance, and diaphragm liquid phase concentration polarization resistance as multiple electrode internal resistances, but is not limited to this.

[0199] As another option of the embodiment of the present application, the method further includes:

[0200] When the number of core packs of the wound cell battery reaches a preset number threshold, the internal resistances of all electrode sheets are summed, and the internal equivalent resistance is obtained according to the summation result;

[0201] Calculate the first DC internal resistance of the wound cell battery based on the external resistance of all electrode sheets, the internal equivalent resistance, and the number of tabs of the wound cell battery;

[0202] Using the first DC internal resistance as the DC internal resistance of the wound cell battery; or

[0203] When the number of core packs of the wound cell battery exceeds a preset threshold, a second DC internal resistance of the wound cell battery is calculated based on the first DC internal resistance, the external resistances of all electrode sheets, and the number of core packs of the wound cell battery;

[0204] The second DC internal resistance is used as the DC internal resistance of the wound cell battery.

[0205] Specifically, after obtaining the DC internal resistance decomposition result of the wound cell battery, the control terminal can also calculate the DC internal resistance decomposition result based on the number of core packs of the wound cell battery to obtain the DC internal resistance of the wound cell battery. It can be understood that when the number of core packs of the wound cell battery is a preset number threshold, it indicates that the wound cell battery is a single core pack, that is, the preset number threshold is 1, and then the internal resistance of all electrode sheets can be summed. For example, the positive electrode electron transfer resistance, negative electrode electron transfer resistance, positive electrode electrochemical polarization resistance, negative electrode electrochemical polarization resistance, and diaphragm liquid phase concentration polarization resistance mentioned above can be summed, and half of the summed result is used as the internal equivalent resistance.

[0206] Next, see Figure 3 The schematic diagram of the decomposition equivalent circuit of the DC internal resistance of a wound battery cell provided in an embodiment of the present application is shown. Substituting all the external resistances of the electrode sheets, the internal equivalent resistances, and the number of tabs of the wound battery cell into a preset first DC internal resistance calculation formula, the first DC internal resistance of the wound battery cell (i.e., the DC internal resistance of a single-core wound battery cell) is obtained. Here, the preset first DC internal resistance calculation formula can be, but is not limited to, the following:

[0207]

[0208] In the above formula, Rn may be the first DC internal resistance, n may be the number of positive electrode ears, R1 may be the positive electrode ohmic resistance, R2 may be the negative electrode ohmic resistance, R3 may be the resistance of a single positive electrode ear, R4 may be the resistance of a single negative electrode ear, R5 may be the positive electrode electron transfer resistance, R6 may be the negative electrode electron transfer resistance, R7 may be the positive electrode electrochemical polarization resistance, R8 may be the negative electrode electrochemical polarization resistance, and R9 may be the diaphragm liquid phase concentration polarization resistance. This is the internal equivalent resistance.

[0209] It can also be understood that when the number of core packs of the wound cell battery exceeds the preset number threshold, it indicates that the number of core packs of the wound cell battery is at least two, and then the first DC internal resistance, all electrode external resistances, and the number of core packs of the wound cell battery can be substituted into the preset second DC internal resistance calculation formula to obtain the second DC internal resistance of the wound cell battery (i.e., the DC internal resistance of the multi-core pack wound cell battery). Here, the preset second DC internal resistance calculation formula can be, but is not limited to, as follows:

[0210]

[0211] In the above formula, R all can be the second DC internal resistance, k can be the number of core packages, R n It can be the first DC internal resistance calculated above, R1 can be the positive electrode ohmic resistance, and R2 can be the negative electrode ohmic resistance.

[0212] It should be noted that in order to verify the accuracy of the DC internal resistance simulation decomposition of the wound battery cell used in this application, the test conditions can also be taken as an example: 30% SOC, charging current rate 2C, and charging 10s. The DC internal resistance of a certain square wound battery cell product is subjected to simulation decomposition processing and conventional actual measurement processing known in the art, and the decomposition result corresponding table shown below is obtained:

[0213]

[0214] It can be seen that the DC internal resistance simulation decomposition method of the present application can obtain more refined resistance; secondly, since the data obtained by conventional measurement processing will have certain errors, for example, there is a large difference between the positive electron transfer resistance and the negative electron transfer resistance, but the reason for the large difference is that the positive electron transfer resistance and the negative electron transfer resistance are replaced by the diaphragm resistance during conventional measurement, that is, the difference will be large due to the inclusion of contact resistance; secondly, except for the positive electron transfer resistance and the negative electron transfer resistance, all other types of resistance have small differences, and the error of the final total resistance (that is, the DC internal resistance) is small, which proves the accuracy of the DC internal resistance simulation decomposition method of the present application.

[0215] As another option of the embodiment of the present application, the method further includes:

[0216] The internal resistance of all electrodes is summed up, and based on the internal resistance of each electrode and the summed result, the corresponding resistance ratio is obtained;

[0217] Based on the proportion of all resistance values, the DC internal resistance analysis results of the wound cell battery are determined.

[0218] Specifically, taking the internal resistances of all electrode sheets including the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance, the positive electrode charge transfer resistance, the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance, the diaphragm liquid phase concentration polarization resistance, the negative electrode solid electrolyte interface film resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance as an example, the control terminal can also sum up the internal resistances of all electrode sheets, and calculate the resistance ratio between each electrode sheet internal resistance and the summed result, so as to determine the DC internal resistance analysis result of the wound battery cell based on the ratio of all resistance values.

[0219] Also see here Figure 4 The schematic diagram of the internal resistance decomposition ratio of the electrode sheet of a wound battery cell provided in an embodiment of the present application is shown as follows: Figure 4 As shown in the decomposition ratio diagram, the sum of the resistance ratios of the positive electrode electron transfer resistance and the negative electrode electron transfer resistance is approximately equal to 0%, the resistance ratio of the positive electrode liquid phase concentration polarization resistance is approximately 2%, the resistance ratio of the positive electrode solid phase concentration polarization resistance is approximately 13%, the resistance ratio of the positive electrode charge transfer resistance is approximately 10%, the resistance ratio of the negative electrode liquid phase concentration polarization resistance is approximately 3%, the resistance ratio of the negative electrode solid phase concentration polarization resistance is approximately 22%, the resistance ratio of the negative electrode charge transfer resistance is approximately 31%, the resistance ratio of the negative electrode solid electrolyte interface film resistance is approximately 14%, and the resistance ratio of the diaphragm liquid phase concentration polarization resistance is approximately 5%.

[0220] It is understandable that when determining the DC internal resistance analysis result of the wound cell battery based on the proportion of all resistance values, it can be but not limited to when it is detected that the resistance proportion of the diaphragm liquid phase concentration polarization resistance exceeds the preset first proportion threshold, indicating that the reason for the large DC internal resistance may be that the lithium ion transmission in the electrolyte in the diaphragm is slow. On the one hand, it may be that the electrolyte conductivity or diffusion coefficient is low, and on the other hand, it may be that the diaphragm is too thick or not tightly fitted with gaps; then, when the resistance proportion of the positive electrode liquid phase concentration polarization resistance and the negative electrode liquid phase concentration polarization resistance is detected When the sum of the resistance ratios of the positive electrode liquid phase concentration polarization resistance and the negative electrode liquid phase concentration polarization resistance does not exceed the preset second proportion threshold, it indicates that the main reason is that the diaphragm is too thick or not tightly fitted with gaps, and then the diaphragm is too thick or not tightly fitted with gaps as the DC internal resistance analysis result of the wound cell battery, and is not limited to this.

[0221] Of course, when the control terminal detects that the resistance value of the positive electrode solid phase concentration polarization resistance accounts for a large proportion, it can indicate that the solid phase diffusion of lithium ions is slow, and then the large particle size of the positive electrode lithium iron phosphate can be used as the DC internal resistance analysis result of the wound battery cell, which is also not limited to this.

[0222] See next Figure 5 , Figure 5 A schematic structural diagram of a DC internal resistance simulation and decomposition device for wound battery cells provided in an embodiment of the present application is shown.

[0223] like Figure 5 As shown, the DC internal resistance simulation decomposition device for wound battery cells may include at least a first decomposition module 501, a parameter acquisition module 502, and a second decomposition module 503, wherein:

[0224] A first decomposition module 501 is configured to calculate at least two types of electrode sheet external resistances based on structural dimension parameters of the wound cell battery;

[0225] The parameter acquisition module 502 is used to obtain material fluid parameters of the wound cell battery and perform simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain material physical parameters of the wound cell battery;

[0226] The second decomposition module 503 is used to calculate at least two types of electrode internal resistances based on the physical parameters of the materials, and use all electrode external resistances and all electrode internal resistances as the DC internal resistance decomposition result of the wound cell battery.

[0227] Those skilled in the art will clearly understand that the technical solutions of the embodiments of the present application can be implemented with the help of software and / or hardware. "Unit" and "module" in this specification refer to software and / or hardware that can independently perform or cooperate with other components to perform specific functions, where the hardware can be, for example, a field programmable gate array (FPGA), an integrated circuit (IC), etc.

[0228] See next Figure 6 , Figure 6 A schematic structural diagram of another device for simulating and decomposing the DC internal resistance of wound battery cells provided in an embodiment of the present application is shown.

[0229] like Figure 6 As shown, the DC internal resistance simulation and decomposition device 600 for wound battery cells may include at least one processor 601 , at least one network interface 604 , a user interface 603 , a memory 605 , and at least one communication bus 602 .

[0230] The communication bus 602 may be used to implement connection and communication among the above components.

[0231] The user interface 603 may include buttons, and the optional user interface may also include a standard wired interface or a wireless interface.

[0232] The network interface 604 may include, but is not limited to, a Bluetooth module, an NFC module, a Wi-Fi module, and the like.

[0233] Among them, the processor 601 may include one or more processing cores. The processor 601 uses various interfaces and lines to connect the various parts of the DC internal resistance simulation and decomposition device 600 for wound battery cells, and executes various functions and processes data of the DC internal resistance simulation and decomposition device 600 for wound battery cells by running or executing instructions, programs, code sets or instruction sets stored in the memory 605, and calling data stored in the memory 605. Optionally, the processor 601 can be implemented in at least one hardware form of DSP, FPGA, and PLA. The processor 601 can integrate one or a combination of CPU, GPU, and modem. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; and the modem is used to handle wireless communications. It is understandable that the above-mentioned modem may not be integrated into the processor 601, but may be implemented separately through a chip.

[0234] Among them, the memory 605 may include RAM and may also include ROM. Optionally, the memory 605 includes a non-transitory computer-readable medium. The memory 605 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 605 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 605 may also be optionally at least one storage device located away from the aforementioned processor 601. As Figure 6 As shown, the memory 605 as a computer storage medium may include an operating system, a network communication module, a user interface module, and an application program for simulating and decomposing the DC internal resistance of wound battery cells.

[0235] Specifically, the processor 601 may be configured to call an application program for simulating and decomposing the DC internal resistance of wound battery cells stored in the memory 605 and specifically perform the following operations:

[0236] Calculate at least two types of electrode external resistances based on the structural size parameters of the wound cell battery;

[0237] Obtaining the material fluid parameters of the wound cell battery, and performing simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain the material physical parameters of the wound cell battery;

[0238] At least two types of pole piece internal resistances are calculated based on the physical parameters of the material, and all pole piece external resistances and all pole piece internal resistances are used as the DC internal resistance decomposition results of the wound cell battery.

[0239] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0240] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interface, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0241] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0242] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0243] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes a number of instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned memory includes: various media that can store program codes, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

Claims

1. A method for simulating and decomposing the DC internal resistance of a wound battery cell, characterized in that: include: At least two types of electrode sheet external resistances are calculated based on the structural dimensional parameters of the wound cell battery; the structural dimensional parameters of the wound cell battery include the resistivity of the positive electrode column, the thickness of the positive electrode column, the minimum cross-sectional area of ​​the positive electrode column, the total thickness of the positive electrode connecting piece welding, the positive laser welding print area, the positive electrode effective length, the cross-sectional area of ​​the positive electrode connecting piece, the total thickness of the positive electrode ear welding, the total area of ​​the positive electrode welding print, the resistivity of the negative electrode column, the thickness of the negative electrode column, the minimum cross-sectional area of ​​the negative electrode column, the total thickness of the negative electrode connecting piece welding, the negative laser welding print area, the negative electrode effective length, the cross-sectional area of ​​the negative electrode connecting piece, the total thickness of the negative electrode ear welding, the total area of ​​the negative electrode welding print, the length of the positive electrode ear welding area, the cross-sectional area of ​​a single positive electrode ear, the length of the negative electrode ear welding area and the cross-sectional area of ​​a single negative electrode ear; all the electrode sheet external resistances include the positive electrode ohmic resistance, the negative electrode ohmic resistance, the single positive ear resistance and the single negative ear resistance; Obtaining material fluid parameters of the wound cell battery, and performing simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain material physical parameters of the wound cell battery; the material fluid parameters of the wound cell battery include the thickness, particle size, solid phase volume fraction, liquid phase volume fraction, exchange current density, solid phase diffusion coefficient, density, gram capacity, electrolyte solubility, transfer coefficient, transfer coefficient correction coefficient and temperature corresponding to the positive electrode sheet, the negative electrode sheet and the separator respectively; At least two types of electrode internal resistances are calculated based on the physical parameters of the material, and all the electrode external resistances and all the electrode internal resistances are used as the DC internal resistance decomposition results of the wound battery cell; all the electrode internal resistances include the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance.

2. The method according to claim 1, characterized in that The method further comprises: When the number of core packs of the wound cell battery reaches a preset number threshold, summing the internal resistances of all the electrode sheets and obtaining an internal equivalent resistance based on the summation result; Calculating a first DC internal resistance of the wound cell battery based on all the electrode sheet external resistances, the internal equivalent resistance, and the number of electrode tabs of the wound cell battery; Using the first DC internal resistance as the DC internal resistance of the wound cell battery; or When the number of core packs of the wound cell battery exceeds the preset number threshold, calculating a second DC internal resistance of the wound cell battery based on the first DC internal resistance, all the electrode sheet external resistances, and the number of core packs of the wound cell battery; The second DC internal resistance is used as the DC internal resistance of the wound cell battery.

3. The method according to claim 1, characterized in that The calculation of at least two types of electrode sheet external resistances based on the structural dimension parameters of the wound cell battery includes: Calculating the positive electrode column resistance according to the positive electrode column resistivity, the positive electrode column thickness, and the minimum cross-sectional area of ​​the positive electrode column; Calculating the positive electrode laser welding resistance based on the positive electrode column resistivity, the total welding thickness of the positive electrode connecting piece, and the positive laser welding area; Calculating the positive electrode connecting piece resistance according to the positive electrode column resistivity, the positive electrode effective length, and the positive electrode connecting piece cross-sectional area; Calculating the positive electrode ultrasonic weld resistance based on the positive electrode column resistivity, the total positive electrode tab weld thickness, and the total positive electrode weld area, and summing the positive electrode column resistance, the positive electrode laser weld resistance, the positive electrode connector resistance, and the positive electrode ultrasonic weld resistance to obtain the positive electrode ohmic resistance; Calculating the resistance of the negative electrode column according to the resistivity of the negative electrode column, the thickness of the negative electrode column, and the minimum cross-sectional area of ​​the negative electrode column; Calculating the negative electrode laser welding resistance according to the negative electrode column resistivity, the total welding thickness of the negative electrode connecting piece, and the negative laser welding area; Calculating the negative electrode connecting piece resistance according to the negative electrode column resistivity, the negative electrode effective length, and the negative electrode connecting piece cross-sectional area; Calculating the negative electrode ultrasonic weld resistance according to the negative electrode column resistivity, the total thickness of the negative electrode tab weld, and the total area of ​​the negative electrode weld mark, and summing the negative electrode column resistance, the negative electrode laser weld resistance, the negative electrode connector resistance, and the negative electrode ultrasonic weld resistance to obtain the negative electrode ohmic resistance; The positive electrode ohmic resistor and the negative electrode ohmic resistor are used as at least two types of electrode external resistors.

4. The method according to claim 3, characterized in that The method of using the positive electrode ohmic resistor and the negative electrode ohmic resistor as at least two types of electrode external resistors further includes: Calculating a single positive tab resistance based on the positive electrode column resistivity, the positive tab welding area length, and the single positive tab cross-sectional area; Calculating a single negative tab resistance based on the negative electrode column resistivity, the negative tab welding area length, and the single negative tab cross-sectional area; The positive electrode ohmic resistor, the negative electrode ohmic resistor, the single positive electrode tab resistor and the single negative electrode tab resistor are used as at least two types of electrode external resistors.

5. The method according to any one of claims 1 to 4, characterized in that The material physical parameters include at least two moments, and at least two positive electrode region liquid potentials, at least two positive electrode region solid phase potentials, the liquid phase potential of the positive electrode-diaphragm interface, at least two positive electrode solid phase lithium concentrations, the positive electrode surface lithium concentration, the positive electrode maximum lithium concentration, current, at least two negative electrode region liquid phase potentials, at least two negative electrode region solid phase potentials, the liquid phase potential of the negative electrode-diaphragm interface, at least two negative electrode solid phase lithium concentrations, the negative electrode surface lithium concentration and the negative electrode maximum lithium concentration corresponding to each moment; The calculating of at least two types of internal resistances of the electrode pieces according to the physical parameters of the material includes: Determining a target time from all the times based on the specified charge and discharge parameters, and performing average processing on the liquid phase potentials of all the positive electrode regions corresponding to the target time to obtain an average liquid phase potential of the positive electrode region; Calculating the positive electrode liquid phase concentration polarization resistance based on the average liquid phase potential of the positive electrode region, the liquid phase potential of the positive electrode-separator interface, and the current corresponding to the target time; performing mean processing on all the positive electrode solid phase lithium concentrations and the positive electrode surface lithium concentrations corresponding to the target time to obtain a positive electrode solid phase average lithium concentration, and calculating the positive electrode solid phase concentration polarization resistance according to the positive electrode solid phase average lithium concentration, the positive electrode surface lithium concentration corresponding to the target time, the positive electrode maximum lithium concentration, and the current; averaging the solid-phase potentials of all the positive electrode regions corresponding to the target time to obtain a positive electrode region solid-phase average potential, and calculating the positive electrode charge transfer resistance based on the positive electrode region liquid-phase average potential, the positive electrode region solid-phase average potential, the positive electrode surface lithium concentration corresponding to the target time, the positive electrode maximum lithium concentration, and the current; Summing the positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance, and the positive electrode charge transfer resistance to obtain a positive electrode electrochemical polarization resistance; performing average processing on the liquid phase potentials of all the negative electrode regions corresponding to the target time to obtain an average liquid phase potential of the negative electrode region; Calculating the negative electrode liquid phase concentration polarization resistance according to the average liquid phase potential of the negative electrode region, the liquid phase potential of the negative electrode-separator interface, and the current corresponding to the target time; performing mean processing on all the negative electrode solid phase lithium concentrations and the negative electrode surface lithium concentrations corresponding to the target time to obtain a negative electrode solid phase average lithium concentration, and calculating the negative electrode solid phase concentration polarization resistance according to the negative electrode solid phase average lithium concentration, the negative electrode surface lithium concentration corresponding to the target time, the negative electrode maximum lithium concentration, and the current; performing an average processing on the solid phase potentials of all the negative electrode regions corresponding to the target time to obtain a negative electrode region solid phase average potential, and calculating the negative electrode charge transfer resistance based on the negative electrode region liquid phase average potential, the negative electrode region solid phase average potential, the negative electrode surface lithium concentration corresponding to the target time, the negative electrode maximum lithium concentration, the current, and the negative electrode solid electrolyte interface film resistance; Summing the negative electrode liquid phase concentration polarization resistance, the negative electrode solid phase concentration polarization resistance, the negative electrode charge transfer resistance, and the negative electrode solid electrolyte interface film resistance to obtain the negative electrode electrochemical polarization resistance; According to the liquid phase potential of the positive electrode-diaphragm interface, the liquid phase potential of the negative electrode-diaphragm interface and the current corresponding to the target moment, the diaphragm liquid phase concentration polarization resistance is calculated, and the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance and the diaphragm liquid phase concentration polarization resistance are used as at least two electrode internal resistances.

6. The method according to claim 5, characterized in that The material physical parameters also include total polarization overpotential; The method of using the positive electrode electrochemical polarization resistor, the negative electrode electrochemical polarization resistor and the diaphragm liquid phase concentration polarization resistor as at least two types of electrode internal resistors further includes: Calculate the positive electrode electron transfer resistance and the negative electrode electron transfer resistance respectively according to the total polarization overpotential, the positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the current corresponding to the target time, the conductivity of the positive electrode sheet material, and the conductivity of the negative electrode sheet material; The positive electrode electrochemical polarization resistance, the negative electrode electrochemical polarization resistance, the diaphragm liquid phase concentration polarization resistance, the positive electrode electron transfer resistance and the negative electrode electron transfer resistance are used as at least two types of electrode internal resistances.

7. The method according to claim 1, characterized in that The method further comprises: Summing the internal resistances of all the electrode pieces, and obtaining a corresponding resistance ratio based on the internal resistance of each electrode piece and the summed result; According to the proportions of all the resistance values, a DC internal resistance analysis result of the wound cell battery is determined.

8. A device for simulating and decomposing the DC internal resistance of a wound battery cell, characterized in that: The device is applied to the DC internal resistance simulation decomposition method for a wound battery cell according to any one of claims 1 to 7, and the device comprises: A first decomposition module is used to calculate at least two types of electrode sheet external resistances based on the structural size parameters of the wound cell battery; A parameter acquisition module is used to obtain material fluid parameters of the wound cell battery, and perform simulation modeling and solution processing on the material fluid parameters according to a preset electrochemical model to obtain material physical parameters of the wound cell battery; The second decomposition module is used to calculate at least two types of pole piece internal resistances based on the physical parameters of the material, and use all the pole piece external resistances and all the pole piece internal resistances as the DC internal resistance decomposition result of the wound cell battery.

9. A DC internal resistance simulation decomposition device for wound battery cells, characterized in that: including a processor and a memory; The processor is connected to the memory; The memory is used to store executable program code; The processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory, so as to execute the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a computer or a processor, the computer or the processor executes the steps of the method according to any one of claims 1 to 7.

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