Direct-current internal resistance simulation decomposition method and device for winding battery cell

Abstract

The invention belongs to the technical field of lithium battery direct-current internal resistance testing, and discloses a direct-current internal resistance simulation decomposition method and device for a wound cell, and the method comprises the steps: calculating the external resistance of at least two pole pieces based on the structural size parameters of a wound cell battery; then, acquiring material fluid parameters of the wound cell battery, and performing simulation modeling solving processing on the material fluid parameters according to a preset electrochemical model to obtain material physical parameters of the wound cell battery; then, internal resistances of at least two pole pieces are calculated based on material physical parameters, and all the external resistances of the pole pieces and all the internal resistances of the pole pieces are used as direct-current internal resistance decomposition results of the winding cell battery, so that battery manufacturing and actual testing are not needed, and production testing resources and cost are effectively saved; and the direct current internal resistance of the wound cell battery can be subdivided into a plurality of pole piece external resistors and a plurality of pole piece internal resistors, so that beneficial forward guidance is provided for the structural design of the wound cell battery.

Description

Technical Field

[0001] The present application belongs to the technical field of direct current internal resistance testing of lithium batteries, and in particular relates to a method and device for simulating and decomposing the direct current internal resistance of a wound battery cell. 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 caused will also cause the internal temperature of the battery cell to rise, thereby affecting the life and safety of the battery cell. 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 method is not only too dependent on manual experience, but also the internal resistance decomposition result is not precise enough. The other method is to conduct electrochemical impedance spectroscopy testing on lithium batteries to further decompose the internal resistance results obtained from the test. The whole process is completely dependent on the actual measurement of battery manufacturing. Not only is the testing and data processing process too cumbersome, time-consuming and labor-intensive, but there is also the problem that the internal resistance decomposition result is not precise enough. Summary of the invention

[0004] In order to solve the technical defects that the existing internal resistance decomposition methods mentioned above are too 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 fine enough, this application proposes a DC internal resistance simulation decomposition method and device for wound battery cells, including:

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

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

[0007] 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;

[0008] At least two types of pole piece internal resistances are calculated based on the physical parameters of the materials, 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 the pole pieces 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 pole pieces, the internal equivalent resistance and the number of pole 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 number threshold, a second DC internal resistance of the wound cell battery is calculated based on the first DC internal resistance, all electrode sheet external resistances, 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 scheme of the first aspect, the structural size parameters of the wound battery cell 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 welding thickness of the positive electrode connecting piece, the positive laser welding print area, the effective length of the positive electrode, the cross-sectional area of ​​the positive electrode connecting piece, the total welding thickness of the positive electrode ear, the total welding print area of ​​the positive electrode, 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 welding thickness of the negative electrode connecting piece, the negative laser welding print area, the effective length of the negative electrode, the cross-sectional area of ​​the negative electrode connecting piece, the total welding thickness of the negative electrode ear and the total welding print area of ​​the negative electrode;

[0016] At least two types of pole piece external resistances are calculated based on the structural dimension parameters of the wound cell battery, including:

[0017] The resistance of the positive electrode column is calculated according to the resistivity of the positive electrode column, the thickness of the positive electrode column and the minimum cross-sectional area of ​​the positive electrode column;

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

[0019] The resistance of the positive electrode connecting piece is calculated according to the resistivity of the positive electrode column, the effective length of the positive electrode and the cross-sectional area of ​​the positive electrode connecting piece;

[0020] According to the resistivity of the positive electrode column, the total thickness of the positive electrode ear welding and the total area of ​​the positive electrode welding mark, the positive electrode ultrasonic welding mark resistance is calculated, and the positive electrode column resistance, the positive electrode laser welding resistance, the positive electrode connecting piece resistance and the positive electrode ultrasonic welding mark resistance are summed to obtain the positive electrode ohmic resistance;

[0021] Calculate 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;

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

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

[0024] According to the resistivity of the negative electrode column, the total thickness of the negative electrode ear welding and the total area of ​​the negative electrode weld print, the negative electrode ultrasonic weld print resistance is calculated, and the negative electrode column resistance, the negative electrode laser welding resistance, the negative electrode connecting piece resistance and the negative electrode ultrasonic weld print 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 sheet 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 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;

[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] The resistance of a single positive lug is calculated based on the resistivity of the positive pole column, the length of the positive lug welding area, and the cross-sectional area of ​​a single positive lug;

[0029] The resistance of a single negative pole ear is calculated based on the resistivity of the negative pole column, the length of the negative pole ear welding area, and the cross-sectional area of ​​a single negative pole ear;

[0030] The positive electrode ohmic resistor, the negative electrode ohmic resistor, a single positive electrode ear resistor and a single negative electrode ear resistor are used as at least two types of electrode sheet external resistors.

[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-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;

[0032] At least two types of internal resistance of the electrode are calculated 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, and 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 positive electrode lithium concentration and the current;

[0037] The positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance are summed to obtain the positive electrode electrochemical polarization 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] The concentration polarization resistance of the negative electrode liquid phase is calculated based on the average potential of the liquid phase in the negative electrode region, the liquid phase potential at the negative electrode-diaphragm interface, and the current corresponding to the target time;

[0040] All the negative electrode solid phase lithium concentrations and negative electrode surface lithium concentrations corresponding to the target time are averaged 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, and 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 negative electrode lithium concentration, the current, and the negative electrode solid electrolyte interface film resistance;

[0042] 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 are summed to obtain the negative electrode electrochemical polarization 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 time, 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 yet 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 difference polarization resistance are used as at least two types of pole piece internal resistances, and also include:

[0046] 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 electron transfer resistance and the negative electrode electron transfer resistance are calculated respectively;

[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 pole pieces is summed up, and based on the internal resistance of each pole piece and the summed result, the corresponding resistance value ratio is obtained;

[0050] According to 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 DC internal resistance simulation decomposition device for a wound battery cell, comprising:

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

[0053] A parameter acquisition module is used to acquire material fluid parameters of the wound cell battery, and simulate and model the material fluid parameters according to a preset electrochemical model to obtain 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 DC internal resistance simulation decomposition device for 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 codes;

[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 a wound battery cell 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 sheet 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 sheet internal resistances are calculated based on the material physical parameters, and all electrode sheet external resistances and all electrode sheet internal resistances are used as the DC internal resistance decomposition results of the wound cell battery, which not only eliminates the need to manufacture batteries and conduct actual tests, effectively saving production test resources and costs, but also subdivides the DC internal resistance of the wound cell battery into a variety of electrode sheet external resistances and a variety of electrode sheet 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 drawings required for use in the embodiments will be briefly introduced below. 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 paying creative work.

[0063] Figure 1 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;

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

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

[0066] Figure 4 A schematic diagram of the internal resistance decomposition ratio 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 a wound battery cell 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 clearly and completely described 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, and 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 recorded. 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, although the embodiment may not be clearly recorded 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 functions and arrangements of the elements described without departing from the scope of the present application. Various processes or components may be appropriately omitted, substituted or added to each example. 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 for 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 artificial experience: ohmic internal resistance, electrochemical polarization internal resistance and concentration polarization internal resistance. That is, by testing the preset charge and discharge time of the lithium battery to obtain a DC internal resistance sequence, 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 can be 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, and can only rely on artificial 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, and to make symmetrical batteries to obtain diaphragm internal resistance and membrane resistance, and then decompose the DC internal resistance of the battery 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 refined enough. Some internal resistance types have problems such as unclear physical nature or vague concepts, and the entire decomposition process is completely dependent 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, the present 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 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 is shown.

[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 pole piece 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 cells can be but is not limited to being applied 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 resistors 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 resistors 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 sheet, a negative electrode post, a negative connecting sheet, 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 when designing the wound cell battery can be combined with the composition structure of the wound cell battery, and can be divided into structural dimension parameters and material fluid parameters. The structural dimension parameters can include but are not limited to 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 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 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 effective length of the negative electrode, the cross-sectional area of ​​the negative electrode connecting piece, and the 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 the positive electrode sheet, the negative electrode sheet and the 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 plurality of pole piece external resistances and a plurality of pole piece internal resistances as a whole. The plurality of pole piece external resistances may include but are not limited to 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), 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 positive ear resistance) and a single Negative electrode ear resistance (also known as negative electrode ear resistance), the multiple internal resistances of the electrode sheets may include but are not limited to the positive electrode electrochemical polarization resistance (also subdivided into positive electrode liquid phase concentration polarization resistance, positive electrode solid phase concentration polarization resistance and positive electrode charge transfer resistance), negative electrode electrochemical polarization resistance (also subdivided into negative electrode liquid phase concentration polarization resistance, negative electrode solid phase concentration polarization resistance, negative electrode charge transfer resistance and negative electrode solid electrolyte interface film resistance), diaphragm liquid phase concentration polarization resistance, positive electrode electron transfer resistance and 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, which not only eliminates the need to manufacture batteries and actual tests, effectively saving production testing resources and costs, but also subdivides the DC internal resistance of the wound cell battery into a variety of electrode external resistances and a variety of 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, obtain the structural dimension parameters used by the user in designing the wound cell battery, so as to calculate a plurality of electrode sheet external resistances according to the structural dimension parameters and a preset resistance calculation formula. The plurality of electrode sheet 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 option in the embodiment of the present application, the structural size parameters of the wound battery cell 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 welding thickness of the positive electrode connecting piece, the positive laser welding print area, the effective length of the positive electrode, the cross-sectional area of ​​the positive electrode connecting piece, the total welding thickness of the positive electrode ear, the total welding print area of ​​the positive electrode, 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 welding thickness of the negative electrode connecting piece, the negative laser welding print area, the effective length of the negative electrode, the cross-sectional area of ​​the negative electrode connecting piece, the total welding thickness of the negative electrode ear and the total welding print area of ​​the negative electrode;

[0084] At least two types of pole piece external resistances are calculated based on the structural dimension parameters of the wound cell battery, including:

[0085] The resistance of the positive electrode column is calculated according to the resistivity of the positive electrode column, the thickness of the positive electrode column and the minimum cross-sectional area of ​​the positive electrode column;

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

[0087] The resistance of the positive electrode connecting piece is calculated according to the resistivity of the positive electrode column, the effective length of the positive electrode and the cross-sectional area of ​​the positive electrode connecting piece;

[0088] According to the resistivity of the positive electrode column, the total thickness of the positive electrode ear welding and the total area of ​​the positive electrode welding mark, the positive electrode ultrasonic welding mark resistance is calculated, and the positive electrode column resistance, the positive electrode laser welding resistance, the positive electrode connecting piece resistance and the positive electrode ultrasonic welding mark resistance are summed to obtain the positive electrode ohmic resistance;

[0089] Calculate 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;

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

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

[0092] According to the resistivity of the negative electrode column, the total thickness of the negative electrode ear welding and the total area of ​​the negative electrode weld print, the negative electrode ultrasonic weld print resistance is calculated, and the negative electrode column resistance, the negative electrode laser welding resistance, the negative electrode connecting piece resistance and the negative electrode ultrasonic weld print 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 sheet external resistors.

[0094] Specifically, when calculating the external resistance of multiple electrode pieces, the control terminal may substitute the positive electrode column resistivity, the positive electrode column thickness and the minimum cross-sectional area of ​​the positive electrode column into the preset electrode column resistance calculation formula to calculate the positive electrode column resistance. Here, the preset electrode column resistance calculation formula may 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 welding thickness of the positive electrode connecting piece, and the positive laser welding area into the 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, as follows:

[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, as follows:

[0101]

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

[0103] Here, the effective length of the positive electrode can be understood as the effective length of the positive electrode connection in the current transmission direction. 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, the effective length of the positive electrode is the distance between the two welding areas, that is, the current transmission path, 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 ear welding thickness, and the total positive electrode weld area into the 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, as follows:

[0105]

[0106] In the above formula, R 1-4 It can be the positive electrode ultrasonic welding 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 welding area of ​​the positive electrode.

[0107] Then, the control terminal can 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 understandable that when the control terminal uses the positive electrode ohmic resistance as a kind of electrode sheet external resistance, it can also, but is not limited to, use the above-mentioned 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 to this.

[0108] Of course, when calculating the external resistance of multiple pole pieces, the control terminal can also substitute the negative pole column resistivity, negative pole column thickness and negative pole column minimum cross-sectional area into the preset pole column resistance calculation formula to calculate the negative pole column resistance. Here, the preset pole 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 pole resistivity, the total thickness of the negative pole connecting piece welding, and the negative laser welding area into the preset laser welding resistance calculation formula to calculate the negative pole laser welding resistance. Here, the preset laser welding resistance calculation formula may be, but is not limited to, as follows:

[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, as follows:

[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 pole column resistivity, the total thickness of the negative pole ear welding, and the total area of ​​the negative pole weld print into the preset ultrasonic weld print resistance calculation formula to calculate the negative pole ultrasonic weld print resistance. Here, the preset ultrasonic weld print resistance calculation formula may be, but is not limited to, as follows:

[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 welding, and S8 can be the total negative electrode weld area.

[0120] Then, the control terminal can sum the negative pole column resistance, the negative pole laser welding resistance, the negative pole connecting sheet resistance and the negative pole ultrasonic welding resistance to obtain the negative pole ohmic resistance. It is understandable that the control terminal can use the negative pole ohmic resistance as a pole piece external resistance, but is not limited to using the above-mentioned negative pole column resistance, negative pole laser welding resistance, negative pole connecting sheet resistance and negative pole ultrasonic welding resistance as multiple pole piece external resistances, and is not limited to this.

[0121] As another option of the embodiment of the present application, the structural dimension parameters of the wound cell battery also include 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;

[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] The resistance of a single positive lug is calculated based on the resistivity of the positive pole column, the length of the positive lug welding area, and the cross-sectional area of ​​a single positive lug;

[0124] The resistance of a single negative pole ear is calculated based on the resistivity of the negative pole column, the length of the negative pole ear welding area, and the cross-sectional area of ​​a single negative pole ear;

[0125] The positive electrode ohmic resistor, the negative electrode ohmic resistor, a single positive electrode ear resistor and a single negative electrode ear resistor are used as at least two types of electrode sheet external resistors.

[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 ear welding area length, and the cross-sectional area of ​​a single positive electrode ear into a preset electrode ear resistance calculation formula to calculate the single positive electrode ear resistance. Here, the preset electrode ear resistance calculation formula may be, but is not limited to, as follows:

[0127]

[0128] In the above formula, R3 may be the resistance of a single positive ear, ρ1 may be the resistivity of the positive electrode column, L9 may 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 may be the cross-sectional area of ​​a single positive ear.

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

[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, and 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-cutting edge), S 10 It can be the cross-sectional area of ​​a single negative electrode ear.

[0132] It can be understood 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 sheet 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 sheet resistor and negative electrode ultrasonic welding resistor) as multiple electrode external resistors.

[0133] Step 104 : 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.

[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 types 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 sheets, negative electrode sheets and separators), 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 preset electrochemical model mentioned above 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 regions. By inputting the area of ​​a layer of positive electrode sheet as the effective area, additional dimensions are 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 can be understood 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 the specified working condition load. The partial differential equations may include lithium ion solid phase diffusion equations (extra dimensions), lithium ion solid phase potential distribution equations, lithium ion liquid phase ion distribution equations, lithium ion liquid phase potential distribution equations, and solid-liquid interface electrochemical reaction equations, 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 by, but is not limited to, the diffusion and migration material conservation equations based on the concentrated solution theory:

[0140]

[0141] The lithium ion liquid phase potential distribution equation can be expressed by, but is not limited to, 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 (i.e., the 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, 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 (that is, it means to derive the 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, but it 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, for example but not limited to including 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 pole piece internal resistances based on the physical parameters of the materials, and use all pole piece external resistances and all pole piece 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 a variety of electrode internal resistances based on the material physical parameters and resistance calculation formula of the 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, liquid phase potential of the positive electrode-diaphragm interface, at least two positive electrode solid phase lithium concentrations, positive electrode surface lithium concentration, positive electrode maximum 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, negative electrode surface lithium concentration and negative electrode maximum lithium concentration corresponding to each moment;

[0152] At least two types of internal resistance of the electrode are calculated 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, and 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 positive electrode lithium concentration and the current;

[0157] The positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance are summed to obtain the positive electrode electrochemical polarization 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] The concentration polarization resistance of the negative electrode liquid phase is calculated based on the average potential of the liquid phase in the negative electrode region, the liquid phase potential at the negative electrode-diaphragm interface, and the current corresponding to the target time;

[0160] All the negative electrode solid phase lithium concentrations and negative electrode surface lithium concentrations corresponding to the target time are averaged 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, and 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 negative electrode lithium concentration, the current, and the negative electrode solid electrolyte interface film resistance;

[0162] 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 are summed to obtain the negative electrode electrochemical polarization 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 time, 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 battery cell is at the end of the charge and discharge, and can perform average processing on the liquid phase potentials of all 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, and then calculate 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, referred 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 potential of the liquid phase in the positive electrode region, It can be the liquid phase potential of the positive electrode-diaphragm interface, and i can be the current corresponding to the target time.

[0167] Next, the control terminal can also perform mean 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, and then 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 It 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 processing 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 can also perform mean 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 can be, but is not limited to, as follows:

[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 potential of the positive electrode region, It can be the average liquid potential in the positive electrode region, and i can be the current corresponding to the target moment.

[0173] Next, the control terminal can 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 understandable that when the control terminal uses the positive electrode electrochemical polarization resistance as a kind of electrode internal resistance, it can also, but is not limited to, use 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 can also perform mean 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, and substitute the average liquid phase potential of the negative electrode region, the liquid phase 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, and then calculate the negative electrode liquid phase concentration polarization resistance. Here, the preset negative electrode liquid phase concentration polarization resistance formula can be, but is not limited to, as follows:

[0175]

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

[0177] Next, the control terminal can also perform mean 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, and then 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, as follows:

[0178]

[0179] In the above formula, R 8-2 It can be the negative electrode solid phase concentration polarization resistance, It can be a 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 can also perform mean 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 can be, but is not limited to, as follows:

[0181]

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

[0183] Next, the control terminal can 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 understandable that when the control terminal uses the negative electrode electrochemical polarization resistance as a kind of electrode internal resistance, it can also, but is not limited to, use 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 considered 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 used within the electrolyte safety window, the electrolyte will not oxidize, and at the same time, weak side reactions such as oxidation decomposition of electrolyte lithium salts 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] Then, 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 internal resistance of the electrode. 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-diaphragm interface, It can be the liquid phase potential of the positive electrode-diaphragm interface, and i can be the current corresponding to the target time.

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

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

[0190] 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 electron transfer resistance and the negative electrode electron transfer resistance are calculated respectively;

[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 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 methods), 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 methods), 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] Next, 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 the pole pieces 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 pole pieces, the internal equivalent resistance and the number of pole 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 number threshold, a second DC internal resistance of the wound cell battery is calculated based on the first DC internal resistance, all electrode sheet external resistances, 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 decomposition result of the DC internal resistance of the wound cell battery, the control terminal can also calculate the decomposition result of the DC internal resistance according to 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 pole pieces 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 provided by an embodiment of the present application is shown, so as to substitute all the external resistances of the pole pieces, the internal equivalent resistances and the number of pole tabs of the wound battery into the preset first DC internal resistance calculation formula, and then obtain the first DC internal resistance of the wound battery (that is, the DC internal resistance of the single-core wound battery). 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 electrodes, R1 may be the positive electrode ohmic resistance, R2 may be the negative electrode ohmic resistance, R3 may be the single positive electrode ear resistance, R4 may be the single negative electrode ear resistance, 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, 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 pole piece 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 (that is, 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 the following:

[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 30% SOC, charging current rate 2C and charging 10s as an example, and the DC internal resistance of a 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 detailed resistance; secondly, due to the fact that 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 membrane resistance during conventional measurement, that is, the difference is 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 resistances 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 pole pieces is summed up, and based on the internal resistance of each pole piece and the summed result, the corresponding resistance value ratio is obtained;

[0217] According to 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 pole pieces 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 all the internal resistances of the pole pieces, and calculate the resistance ratio between each internal resistance of the pole piece and the summed result, so as to determine the DC internal resistance analysis result of the wound battery cell according to the ratio of all resistance values.

[0219] Also see here Figure 4 FIG. 1 is a schematic diagram showing the internal resistance decomposition ratio of a pole piece of a wound battery cell provided in an embodiment of the present application. 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 can be understood that when the DC internal resistance analysis result of the wound cell battery is determined 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 values ​​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 battery cell, 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 lithium ion solid phase diffusion 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 a wound battery cell 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 used to calculate at least two types of pole piece external resistances based on the structural size parameters of the wound cell battery;

[0225] The parameter acquisition module 502 is used to acquire 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 pole piece internal resistances based on the physical parameters of the materials, and use all pole piece external resistances and all pole piece internal resistances as the DC internal resistance decomposition result of the wound cell battery.

[0227] Those skilled in the art can clearly understand that the technical solutions of the embodiments of the present application can be implemented with the help of software and / or hardware. The "unit" and "module" in this specification refer to software and / or hardware that can independently complete or cooperate with other components to complete specific functions, where the hardware can be, for example, a field programmable gate array (Field-Programmable Gate Array, FPGA), an integrated circuit (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 a wound battery cell provided in an embodiment of the present application is shown.

[0229] like Figure 6 As shown, the DC internal resistance simulation 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 realize the connection and communication among the above-mentioned 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, etc.

[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 in the DC internal resistance simulation decomposition device 600 for winding batteries, and executes various functions and processes data of the DC internal resistance simulation decomposition device 600 for winding batteries 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, modem, etc. 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; the modem is used to handle wireless communication. It can be understood that the above-mentioned modem may not be integrated into the processor 601, but implemented by a single chip.

[0234] The memory 605 may include RAM or ROM. Optionally, the memory 605 includes a non-transitory computer-readable medium. The memory 605 may 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 method embodiments, etc.; the data storage area may store data involved in the above-mentioned method embodiments, etc. The memory 605 may optionally be 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 a DC internal resistance simulation decomposition application for wound battery cells.

[0235] Specifically, the processor 601 may be used to call the DC internal resistance simulation decomposition application for the wound battery cell stored in the memory 605, and specifically perform the following operations:

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

[0237] 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;

[0238] At least two types of pole piece internal resistances are calculated based on the physical parameters of the materials, 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 emphasis. 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 the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of units, which is only a logical function division. There may be other division methods in actual implementation, 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 interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

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

[0242] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of 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 several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of each embodiment method of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, disk or optical disk, etc., and other media that can store program codes.

Claims

1. A DC internal resistance simulation decomposition method for a wound battery cell, characterized in that: include: Calculate at least two types of pole piece external resistances based on the structural dimension parameters of the wound cell battery; 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; At least two types of pole piece internal resistances are calculated based on the physical parameters of the material, and all the pole piece external resistances and all the pole piece internal resistances are used as the DC internal resistance decomposition result of the wound cell battery.

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 up the internal resistances of all the electrode sheets, and obtaining an internal equivalent resistance according to 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, based on the first DC internal resistance, all the electrode sheet external resistances and the number of core packs of the wound cell battery, a second DC internal resistance of the wound cell battery is calculated; 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 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 welding thickness of the positive electrode connecting piece, the positive laser welding print area, the effective length of the positive electrode, the cross-sectional area of ​​the positive electrode connecting piece, the total welding thickness of the positive electrode ear, the total welding print area of ​​the positive electrode, 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 welding thickness of the negative electrode connecting piece, the negative laser welding print area, the effective length of the negative electrode, the cross-sectional area of ​​the negative electrode connecting piece, the total welding thickness of the negative electrode ear and the total welding print area of ​​the negative electrode; The at least two types of pole piece external resistances are calculated based on the structural size parameters of the wound cell battery, including: Calculating the resistance of the positive electrode column according to the resistivity of the positive electrode column, the thickness of the positive electrode column and the minimum cross-sectional area of ​​the positive electrode column; Calculating the positive electrode laser welding resistance according to 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; According to the resistivity of the positive electrode column, the total welding thickness of the positive electrode ear and the total area of ​​the positive electrode weld print, the positive electrode ultrasonic weld print resistance is calculated, and the positive electrode column resistance, the positive electrode laser welding resistance, the positive electrode connecting piece resistance and the positive electrode ultrasonic weld print resistance are summed 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 resistance of the negative electrode connecting piece according to the resistivity of the negative electrode column, the effective length of the negative electrode and the cross-sectional area of ​​the negative electrode connecting piece; According to the resistivity of the negative electrode column, the total thickness of the negative electrode ear welding and the total area of ​​the negative electrode weld print, the negative electrode ultrasonic weld print resistance is calculated, and the negative electrode column resistance, the negative electrode laser welding resistance, the negative electrode connecting piece resistance and the negative electrode ultrasonic weld print resistance are summed 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 sheet external resistors.

4. The method according to claim 3, characterized in that The structural dimension parameters of the wound cell battery also include 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; The method of using the positive electrode ohmic resistor and the negative electrode ohmic resistor as at least two types of electrode sheet external resistors also includes: Calculating the resistance of a single positive electrode lug according to the resistivity of the positive electrode column, the length of the positive electrode lug welding area, and the cross-sectional area of ​​the single positive electrode lug; Calculating the resistance of a single negative electrode lug according to the resistivity of the negative electrode column, the length of the negative electrode lug welding area, and the cross-sectional area of ​​the single negative electrode lug; 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 sheet 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 of the moments; The calculating of at least two types of internal resistances of the electrode sheets according to the physical parameters of the materials includes: determining a target time from among 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 according to the average liquid phase potential in the positive electrode region, the liquid phase potential at the positive electrode-diaphragm 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 the 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; Performing mean processing on all the solid phase potentials of the positive electrode regions corresponding to the target time to obtain the average solid phase potential of the positive electrode region, and calculating the positive electrode charge transfer resistance according to 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; The positive electrode liquid phase concentration polarization resistance, the positive electrode solid phase concentration polarization resistance and the positive electrode charge transfer resistance are summed to obtain the 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-diaphragm 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 the 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 mean processing on all the solid phase potentials of the negative electrode regions corresponding to the target time to obtain the average solid phase potential of the negative electrode region, and calculating the negative electrode charge transfer resistance according to 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; 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 are summed 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 types of 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 difference polarization resistor as at least two types of pole piece internal resistors also includes: 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, respectively calculate the positive electrode electron transfer resistance and the negative electrode electron transfer resistance; 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 pole piece internal resistances.

7. The method according to claim 1, characterized in that The method further comprises: The internal resistances of all the pole pieces are summed up, and based on each internal resistance of the pole piece and the summed up result, a corresponding resistance value ratio is obtained; According to all the resistance ratios, the DC internal resistance analysis result of the wound cell battery is determined.

8. A DC internal resistance simulation decomposition device for a wound battery cell, characterized in that: include: A first decomposition module is used to calculate at least two types of pole piece external resistances based on the structural size parameters of the wound cell battery; A parameter acquisition module, used to acquire 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 a wound battery cell, 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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