Method and apparatus for analyzing lithium precipitation of electrode assembly

Abstract

The embodiment of the invention provides a method and equipment for analyzing lithium precipitation of an electrode assembly. The method comprises the following steps: acquiring a representative volume element (RVE) model of the electrode assembly, wherein the RVE model comprises a pole piece module of the electrode assembly; and performing numerical simulation on the electrode assembly according to the RVE model so as to analyze the lithium precipitation condition of the electrode assembly. According to the method and equipment for analyzing lithium precipitation of the electrode assembly, the analysis efficiency and accuracy can be improved, and resource waste is avoided.

Description

Method and apparatus for analyzing lithium deposition in electrode assemblies Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method and device for analyzing lithium deposition in electrode assemblies. Background Art

[0002] Lithium-ion batteries, due to their high energy density and excellent safety performance, have been widely used in pure electric and hybrid vehicles. However, lithium-ion batteries may experience lithium deposition during use, significantly impacting their performance. Therefore, numerical simulations are often used to analyze lithium deposition in batteries.

[0003] When conducting lithium plating analysis on batteries, the established numerical models often have the problem of too many grids, which leads to a large amount of resource waste, complicated calculation process, and low efficiency.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a method and apparatus for analyzing lithium deposition in electrode assemblies, which can improve analysis efficiency and accuracy, and avoid waste of resources.

[0006] In a first aspect, a method for analyzing lithium deposition in an electrode assembly is provided, comprising: obtaining a representative volume element (RVE) model of the electrode assembly, the RVE model including a pole piece module of the electrode assembly; and performing numerical simulation of the electrode assembly according to the RVE model to analyze the lithium deposition of the electrode assembly.

[0007] Therefore, the method for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application performs numerical simulation on the electrode assembly through the RVE model of the electrode assembly to analyze the lithium deposition of the electrode assembly. Moreover, unlike the full-scale model, the RVE model adopted in the embodiment of the present application does not require the establishment of the overall structure of the electrode assembly. For example, according to the structural characteristics of the electrode assembly, the RVE model may include a pole piece module of the electrode assembly, which is a part of the electrode assembly. In this way, by inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the occupied resources can be reduced while ensuring the accuracy of the calculation; moreover, the same RVE model can be applied to multiple types of electrode assemblies, that is, different types of electrode assemblies can be simulated, avoiding the process of repeated re-modeling, simplifying the calculation and modeling process, and improving the efficiency of the simulation.

[0008] In some embodiments, the electrode module includes a planar region, the planar region being used to form the largest end face of the electrode assembly; obtaining a representative volume element (RVE) model of the electrode assembly includes determining parameters of the planar region to establish the RVE model, wherein the RVE model includes the planar region. Considering that the electrode modules of either stacked or wound electrode assemblies may include a planar region, the RVE model established based on the parameters of the planar region can be applied to numerical simulations of different types of electrode assemblies.

[0009] In some embodiments, determining the parameters of the planar region includes establishing a governing equation for the planar region based on the effect of stress on the wetting effect of the planar region, wherein the parameters of the planar region include the governing equation for the planar region. By considering the effect of stress on the wetting effect, the RVE model can be made to more closely reflect the changes in the electrode assembly during the charge and discharge process during actual battery cell use, resulting in more accurate simulation results.

[0010] In some embodiments, the control equation for the planar region is established based on the effect of stress on the wetting effect of the planar region, including: determining the porosity of different regions of the planar region based on the stress distribution of different regions of the planar region; determining the seepage velocity of the electrolyte in the planar region based on the porosity of different regions of the planar region based on Darcy's law, and the control equation for the planar region includes the seepage velocity of the electrolyte in the planar region. Since stress can cause the material on the surface of the electrode to expand or contract, stress will affect the porosity of different regions of the electrode; and according to Darcy's law, the porosity is proportional to the magnitude of the seepage velocity of the electrolyte in the corresponding region. Therefore, an equation for the seepage velocity of the corresponding region can be obtained, and the effect of stress on the wetting effect can be simulated and calculated using this equation, making the RVE model calculation results more accurate.

[0011] In some embodiments, the electrode assembly is a wound electrode assembly, the electrode module includes a bend region, and the bend region is used to form a curved surface of the electrode assembly; obtaining a representative volume element (RVE) model of the electrode assembly includes: determining parameters of the bend region to establish the RVE model, wherein the RVE model includes the bend region. When the parameters of the bend region are considered in the RVE model, the RVE model can be used for wound electrode assemblies having a bend portion to reflect the difference between the bend region and a planar region, making the RVE model more widely applicable and the calculation results more accurate.

[0012] In some embodiments, the determination of the parameters of the bending area includes: establishing a first control equation of the bending area according to the influence of stress on the wetting effect of the bending area, and the parameters of the bending area include the first control equation. Due to the geometric structure of the bending area, there is a gap between the anode electrode and the cathode electrode, which will lead to insufficient electrolyte infiltration of the anode and cathode electrodes on both sides of the isolation membrane, thereby causing the electrochemical reaction kinetics to deteriorate. Moreover, similar to the planar area, for the bending area, during the actual charge and discharge process of the battery cell, as the material on the surface of the electrode sheet expands or contracts due to stress, the corresponding electrolyte will be squeezed out or reflux. Therefore, by considering the influence of stress on the wetting effect, the RVE model can be made closer to the changes in the electrode assembly during the charge and discharge process of the actual battery cell, making the simulation results more accurate.

[0013] In some embodiments, based on the effect of stress on the wetting effect of the bend area, a first control equation for the bend area is established, including: determining the porosity of different areas of the bend area based on the stress distribution of different areas of the bend area; based on Darcy's law, determining the seepage velocity of the electrolyte in the bend area based on the porosity of different areas of the bend area, and the first control equation includes the seepage velocity of the electrolyte in the bend area. Since stress can cause the material on the surface of the electrode to expand or contract, stress will affect the porosity of different areas of the electrode; and according to Darcy's law, the porosity is proportional to the magnitude of the seepage velocity of the electrolyte in the corresponding area. Therefore, an equation for the seepage velocity of the corresponding area can be obtained, and the effect of stress on the wetting effect can be simulated and calculated using this equation, making the calculation results of the RVE model more accurate.

[0014] In some embodiments, determining the parameters of the bending region includes: establishing a second control equation for the bending region based on the effect of the bending region on a preset capacity balance CB value of the electrode assembly, wherein the parameters of the bending region include the second control equation. The second control equation for the bending region can be used to simulate the effect of the bending region on the CB value of the electrode assembly. In particular, when the bending portion of the electrode module in the RVE model differs from the actual shape, the second control equation can be used to simulate the concave and convex surfaces generated by the bending of each electrode in the bending portion, as well as the gap between the cathode and anode electrodes, to distinguish them from the planar portion, thereby increasing the accuracy of the RVE model.

[0015] In some embodiments, based on the influence of the bending region on the capacity balance CB value of the electrode assembly, a second control equation for the bending region is established, including: determining the relationship between the CB value of the bending region and the preset CB value based on the total thickness of the electrode module in the bending region, the distance between the cathode active material layer and the anode active material layer in the bending region, and the number of winding layers of the electrode assembly, so as to establish the second control equation, and the second control equation includes the relationship between the CB value of the bending region and the preset CB value. In this way, by combining the characteristics of the bending region and reasonably adjusting the CB value of the bending region, the RVE model can be made more accurate and the numerical simulation effect more accurate.

[0016] In a second aspect, a method for analyzing lithium deposition in an electrode assembly is provided, comprising: establishing a third control equation based on the influence of stress on the wetting effect of the electrode sheet of the electrode assembly; establishing a simulation model of the electrode assembly based on the parameters of the electrode assembly, the parameters of the electrode assembly including the third control equation; and performing numerical simulation on the electrode assembly based on the simulation model to analyze the lithium deposition of the electrode assembly.

[0017] During the actual charge and discharge process of a battery cell, as the material on the electrode surface expands or contracts due to stress, the corresponding electrolyte will be squeezed out or refluxed, and this factor also has a significant impact on the lithium deposition process. Therefore, the method for analyzing lithium deposition from an electrode assembly in an embodiment of the present application considers the effect of stress on the wetting effect when establishing a simulation model of the electrode assembly, which can make the electrode assembly model more closely resemble the changes in the electrode assembly during the charge and discharge process during actual battery cell use, making the simulation results more accurate.

[0018] In some embodiments, establishing a third control equation based on the effect of stress on the wetting effect of the electrode plate of the electrode assembly includes: determining the porosity of different regions of the electrode plate of the electrode assembly based on the stress distribution of different regions of the electrode plate of the electrode assembly; and determining the electrolyte seepage velocity of the electrode plate of the electrode assembly based on the porosity of different regions of the electrode plate of the electrode assembly based on Darcy's law. The third control equation includes the electrolyte seepage velocity of the electrode plate of the electrode assembly. Since stress may cause the material on the surface of each electrode plate of the electrode assembly to expand or contract, stress affects the porosity of different regions of the electrode plate. According to Darcy's law, porosity is proportional to the electrolyte seepage velocity in the corresponding region. Therefore, an equation for the seepage velocity of the corresponding region can be obtained. The third equation includes the electrolyte seepage velocity of the electrode plate of the electrode assembly. Simulating and calculating the effect of stress on the wetting effect through the third control equation can make the calculation results of the electrode assembly model more accurate.

[0019] In some embodiments, establishing a simulation model of the electrode assembly based on the parameters of the electrode assembly includes: establishing a representative volume element (RVE) model of the electrode assembly based on the parameters of the electrode assembly, wherein the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes, in sequence: a cathode current collector, a cathode active material layer, a separator, an anode active material layer, and an anode current collector. Unlike a full-scale model, the RVE model used in the embodiments of the present application does not require establishing the overall structure of the electrode assembly. By inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the resource usage can be reduced while ensuring calculation accuracy.

[0020] In some embodiments, the electrode module includes a planar region, and establishing a third control equation based on the effect of stress on the wetting effect of the electrode of the electrode assembly includes: establishing a control equation for the planar region based on the effect of stress on the wetting effect of the planar region, wherein the third control equation includes the control equation for the planar region. Considering that the electrode module of a stacked electrode assembly or a wound electrode assembly can include a planar region, the RVE model established based on the parameters of the planar region can be applied to the numerical simulation of different types of electrode assemblies.

[0021] In some embodiments, the electrode assembly is a wound electrode assembly, and the electrode piece module includes a bent region. The third control equation is established based on the influence of stress on the wetting effect of the electrode piece of the electrode assembly, including: establishing a first control equation for the bent region based on the influence of stress on the wetting effect of the bent region, and the third control equation includes the first control equation. When the parameters of the bent region are considered in the RVE model, the RVE model can be used for wound electrode assemblies having a bent portion to reflect the difference between the bent region and the planar region, making the RVE model more widely applicable and the calculation results more accurate.

[0022] In some embodiments, the method includes: establishing a second governing equation for the bend region based on the effect of the bend region on a preset capacity balance (CB) value of the electrode assembly, wherein the parameters of the electrode assembly include the second governing equation. Therefore, the second governing equation for the bend region can simulate the effect of the bend region on the CB value of the electrode assembly. In particular, when the RVE model uses a pole piece module as shown to geometrically model the bend portion, the second governing equation can simulate the concave and convex surfaces generated by the bending of each pole piece in the bend portion, as well as the gap between the cathode and anode pole pieces, to distinguish them from the planar portion, thereby increasing the accuracy of the RVE model.

[0023] In some embodiments, based on the influence of the bending region on the preset capacity balance CB value of the electrode assembly, a second control equation for the bending region is established, including: determining the relationship between the CB value of the bending region and the preset CB value based on the total thickness of the electrode module in the bending region, the distance between the cathode active material layer and the anode active material layer in the bending region, and the number of winding layers of the electrode assembly, so as to establish the second control equation, and the second control equation includes the relationship between the CB value of the bending region and the preset CB value. In this way, by combining the characteristics of the bending region and reasonably adjusting the CB value of the bending region, the RVE model can be made more accurate and the numerical simulation effect more accurate.

[0024] In a third aspect, a method for analyzing lithium deposition in an electrode assembly is provided, comprising: establishing a simulation model of the electrode assembly according to the parameters of the bending portion of the wound electrode assembly, the simulation model including the bending portion; and performing numerical simulation on the electrode assembly according to the simulation model to analyze the lithium deposition of the electrode assembly.

[0025] Therefore, the method for analyzing lithium deposition in electrode assemblies in an embodiment of the present application takes into account that the difference between a wound electrode assembly and a stacked electrode assembly is that the wound electrode assembly has a bending portion. In view of the specific structure of the bending portion included in the wound electrode assembly, a simulation model of the electrode assembly is established according to the parameters of the bending portion, which can make the simulation model more accurate when used for simulating the wound electrode assembly and the calculation results more accurate.

[0026] In some embodiments, the method includes: establishing a first control equation of the bent portion based on the influence of stress on the wetting effect of the bent portion, and the parameters of the bent portion include the first control equation. Due to the geometric structure of the bent portion, there is a gap between the anode electrode and the cathode electrode, which will lead to insufficient electrolyte infiltration of the anode and cathode electrodes on both sides of the separator, thereby causing deterioration of the electrochemical reaction kinetics. Moreover, similar to the planar portion, for the bent portion, during the actual charge and discharge process of the battery cell, as the material on the surface of the electrode sheet expands or contracts due to stress, the corresponding electrolyte will be squeezed out or reflux. Therefore, by considering the influence of stress on the wetting effect, the simulation model of the electrode assembly can be made closer to the changes in the electrode assembly during the charge and discharge process of the actual battery cell, making the simulation results more accurate.

[0027] In some embodiments, based on the effect of stress on the wetting effect of the bend, a first control equation for the bend is established, including: determining the porosity of different regions of the bend based on the stress distribution of different regions of the bend; and determining the seepage velocity of the electrolyte in the bend based on the porosity of different regions of the bend based on Darcy's law. The first control equation includes the seepage velocity of the electrolyte in the bend. Since stress can cause the material on the surface of the electrode to expand or contract, stress will affect the porosity of different regions of the electrode; and according to Darcy's law, the porosity is proportional to the magnitude of the seepage velocity of the electrolyte in the corresponding region. Therefore, an equation for the seepage velocity of the corresponding region can be obtained, and the effect of stress on the wetting effect can be simulated and calculated using this equation, making the calculation results of the simulation model of the electrode assembly more accurate.

[0028] In some embodiments, the simulation model of the electrode assembly is established based on the parameters of the bend portion of the wound electrode assembly, including: establishing a representative volume element (RVE) model of the electrode assembly based on the parameters of the bend portion of the wound electrode assembly, the RVE model including a pole piece module of the electrode assembly, the pole piece module including, in sequence: a cathode current collector, a cathode active material layer, a separator, an anode active material layer, and an anode current collector. Unlike a full-scale model, the RVE model used in the embodiments of the present application does not require the establishment of the overall structure of the electrode assembly. By inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the resource usage can be reduced while ensuring calculation accuracy.

[0029] In some embodiments, the representative volume element RVE model of the electrode assembly is established based on the parameters of the bending portion of the wound electrode assembly, including: establishing the RVE model based on the parameters of the bending area of ​​the pole piece module, the bending area is the area of ​​the pole piece module located at the bending portion, and the parameters of the bending portion include the parameters of the bending area.

[0030] In some embodiments, the method further includes: establishing a second control equation for the bend region based on the effect of the bend region on a preset capacity balance (CB) value of the electrode assembly, wherein the parameters of the bend region include the second control equation. Therefore, the second control equation for the bend region can simulate the effect of the bend region on the CB value of the electrode assembly. In particular, when the RVE model uses a pole piece module as shown to geometrically model the bend portion, the second control equation can simulate the concave and convex surfaces generated by the bending of each pole piece in the bend portion, as well as the gap between the cathode and anode pole pieces, to distinguish them from the planar portion, thereby increasing the accuracy of the RVE model.

[0031] In some embodiments, based on the influence of the bending region on the preset capacity balance CB value of the electrode assembly, a second control equation for the bending region is established, including: determining the relationship between the CB value of the bending region and the preset CB value based on the total thickness of the electrode module in the bending region, the distance between the cathode active material layer and the anode active material layer in the bending region, and the number of winding layers of the electrode assembly, so as to establish the second control equation, and the second control equation includes the relationship between the CB value of the bending region and the preset CB value. In this way, by combining the characteristics of the bending region and reasonably adjusting the CB value of the bending region, the RVE model can be made more accurate and the numerical simulation effect more accurate.

[0032] In a fourth aspect, a device for analyzing lithium deposition in an electrode assembly is provided, which is configured to execute the method of the first aspect or its respective implementations. Specifically, the device includes a unit configured to execute the method of the first aspect or its respective implementations.

[0033] In a fifth aspect, a device for analyzing lithium deposition in an electrode assembly is provided, which is configured to execute the method of the second aspect or its respective implementations. Specifically, the device includes a unit configured to execute the method of the second aspect or its respective implementations.

[0034] In a sixth aspect, a device for analyzing lithium deposition in an electrode assembly is provided, which is used to perform the method of the third aspect or its respective implementations. Specifically, the device includes a unit for performing the method of the third aspect or its respective implementations.

[0035] In a seventh aspect, an apparatus for analyzing lithium deposition in an electrode assembly is provided, comprising a processor and a memory. The memory is configured to store a computer program, and the processor is configured to call and execute the computer program stored in the memory to perform the method of any one of the first to third aspects or their respective implementations.

[0036] In an eighth aspect, a computer-readable storage medium is provided for storing a computer program, which enables a computer to execute the method of any one of the first to third aspects or their respective implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic flow chart of a method for analyzing lithium deposition in an electrode assembly disclosed in one embodiment of the present application;

[0038] FIG2 is a cross-sectional schematic diagram of an electrode assembly disclosed in one embodiment of the present application;

[0039] FIG3 is an enlarged schematic diagram of a partial cross-section of an electrode assembly disclosed in one embodiment of the present application;

[0040] FIG4 is a partial cross-sectional schematic diagram of an electrode assembly disclosed in one embodiment of the present application;

[0041] FIG5 is a schematic flow chart of another method for analyzing lithium deposition in an electrode assembly disclosed in one embodiment of the present application;

[0042] FIG6 is a schematic flow chart of another method for analyzing lithium deposition in an electrode assembly disclosed in an embodiment of the present application;

[0043] FIG7 is a schematic block diagram of a device for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application;

[0044] FIG8 is another schematic block diagram of a device for analyzing lithium deposition in an electrode assembly disclosed in an embodiment of the present application.

[0045] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0046] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0047] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0048] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0049] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0050] The battery referred to in this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. Batteries generally include a housing that encloses one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0051] In some embodiments, the battery cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., but the embodiments of the present application are not limited to this. Generally, a battery cell may also be referred to as a battery cell. The battery cell may be cylindrical, flat, rectangular, or other regular or irregular shapes. The technical solutions of the embodiments of the present application can be applied to battery cells of any shape.

[0052] A battery cell comprises an electrode assembly and an electrolyte. The electrode assembly includes a cathode sheet, an anode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the cathode and anode sheets. The cathode sheet comprises a cathode current collector and a cathode active material layer. The cathode active material layer is coated on the surface of the cathode current collector. The current collector uncoated with the cathode active material layer protrudes from the current collector coated with the cathode active material layer. The current collector uncoated with the cathode active material layer serves as the cathode tab. For lithium-ion batteries, for example, the cathode current collector can be made of aluminum, while the cathode active material layer can be made of materials such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The anode sheet comprises an anode current collector and an anode active material layer. The anode active material layer is coated on the surface of the anode current collector. The current collector uncoated with the anode active material layer protrudes from the current collector coated with the anode active material layer. The current collector uncoated with the anode active material layer serves as the anode tab. The anode current collector can be made of copper, while the anode active material layer can be made of carbon or silicon. To ensure high current flow without melting, multiple cathode tabs are stacked together, and multiple anode tabs are stacked together. The material of the diaphragm may be, for example, polypropylene (PP) or polyethylene (PE).

[0053] The development of battery technology requires simultaneous consideration of multiple design factors, such as energy density, cycle life, discharge capacity, charge / discharge rate, and other performance parameters. During battery use, repeated charge and discharge cycles can cause lithium deposition in the anode plates within the battery cells. This can significantly impact the battery cells. Therefore, when testing battery performance, numerical simulations are often used to analyze the lithium deposition in the anode plates of the battery cells. This can be used to control lithium deposition and improve battery performance.

[0054] Current numerical simulations of battery cells typically use a full-scale approach to model the battery cells or electrode assemblies that require numerical simulation analysis. For example, a full-scale battery cell model, due to its large number of grids, is complex and computationally intensive, leading to a waste of resources. Furthermore, different models must be created for battery cells of different sizes or types. Replacing a battery cell requires remodeling, resulting in a complex and inefficient process.

[0055] Therefore, an embodiment of the present application provides a method and device for analyzing lithium deposition in an electrode assembly. By obtaining a representative volume element (RVE) model of the electrode assembly and performing numerical simulation of the electrode assembly based on the RVE model, the lithium deposition situation of the electrode assembly can be analyzed.

[0056] Figure 1 shows a schematic flow chart of a method 100 for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application. As shown in Figure 1 , the method 100 includes: step 110, obtaining an RVE model of the electrode assembly, the RVE model including the electrode module of the electrode assembly; and step 120, performing a numerical simulation of the electrode assembly based on the RVE model to analyze the lithium deposition of the electrode assembly.

[0057] In an embodiment of the present application, the electrode assembly is numerically simulated by using the RVE model of the electrode assembly to analyze the lithium deposition of the electrode assembly. Moreover, unlike the full-scale model, the RVE model used in the embodiment of the present application does not need to establish the overall structure of the electrode assembly. For example, according to the structural characteristics of the electrode assembly, the RVE model may include a pole piece module of the electrode assembly, and the pole piece module includes a partial structure of the electrode assembly. In this way, by inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the occupied resources can be reduced while ensuring the accuracy of the calculation; moreover, the same RVE model can be applied to multiple types of electrode assemblies, that is, different types of electrode assemblies can be simulated, avoiding the process of repeated re-modeling, simplifying the calculation and modeling process, and improving the efficiency of the simulation.

[0058] It should be understood that the method 100 of the embodiment of the present application can be applied to the numerical simulation of various types of electrode assemblies. For example, the method 100 can be used for wound electrode assemblies or stacked electrode assemblies, but the embodiment of the present application is not limited thereto. A detailed description will be given below with reference to the accompanying drawings.

[0059] FIG2 shows a possible cross-sectional schematic diagram of the electrode assembly 2 of an embodiment of the present application. For ease of explanation, the embodiment of the present application mainly takes the wound electrode assembly 2 shown in FIG2 as an example, but the relevant description is also applicable to other types of electrode assemblies unless otherwise specified, and the embodiment of the present application is not limited thereto. In addition, the cross section shown in FIG2 may be a cross section perpendicular to the winding axis of the electrode assembly 2. As shown in FIG2 , the electrode assembly 2 may include an anode electrode piece 21, a cathode electrode piece 22 and a separator 23. The separator 23 may specifically include a first separator 231 and a second separator 232, wherein the first separator 231 and the second separator 232 are respectively arranged between the anode electrode piece 21 and the cathode electrode piece 22 to electrically isolate the anode electrode piece 21 from the cathode electrode piece 22; the first separator 231 and the second separator 232 may be made of the same material for easy processing.

[0060] FIG3 shows a partial cross-sectional schematic diagram of the anode electrode sheet 21, cathode electrode sheet 22, and separator 23 of an embodiment of the present application. For example, the partial cross-sectional schematic diagram shown in FIG3 can be an enlarged view of a partial area of ​​the cross-sectional diagram of the wound electrode assembly 2 shown in FIG2, and the cross-sectional diagram shown in FIG3 is in the same direction as the cross-sectional diagram shown in FIG2; or, the partial cross-sectional schematic diagram shown in FIG3 can also be a partial cross-sectional schematic diagram of a stacked electrode assembly, but the embodiments of the present application are not limited thereto. Furthermore, the separator 23 shown in FIG3 can be any layer of separator 23 located between the anode electrode sheet 21 and the cathode electrode sheet 22. For example, the separator 23 can include a first separator 231 and / or a second separator 232.

[0061] It should be understood that the electrode assembly 2 in the embodiment of the present application may refer to a component located inside a battery cell where an electrochemical reaction occurs. Specifically, a battery cell may include one or more electrode assemblies 2 and a shell for accommodating the electrode assembly 2. The shell of the embodiment of the present application may be a polyhedral structure. For example, the shell may include a shell and a cover plate, wherein the shell may be a hollow structure with an opening formed at least at one end, and the shape of the cover plate may be adapted to the shape of the shell, and the cover plate is used to cover the opening of the shell to form a closed cavity for placing the electrode assembly 2, and the internal environment of the battery cell is isolated from the external environment by the shell.

[0062] Depending on actual usage requirements, one or more electrode assemblies 2 can be provided within the housing. Any electrode assembly 2 can include tabs and a main body. Specifically, the anode electrode sheet 21 of the electrode assembly 2 in the embodiment of the present application includes an anode current collector 211 and an anode active material layer 212 located on either side of the anode current collector 211. Similarly, the cathode electrode sheet 22 includes a cathode current collector 221 and a cathode active material layer 222 located on either side of the cathode current collector 221. The electrode assembly 2 can include at least two tabs, which can include a cathode tab and an anode tab. The cathode tab can be formed by stacking the portion of the cathode electrode sheet 22 not coated with the cathode active material layer 222, and the anode tab can be formed by stacking the portion of the anode electrode sheet 21 not coated with the anode active material layer 212. The main body of the electrode assembly 2 can be formed by stacking or winding the portion of the cathode electrode sheet 22 coated with the cathode active material layer 222 and the portion of the anode electrode sheet 21 coated with the anode active material layer 212. For example, a plurality of anode plates 21 and a plurality of cathode plates 22 are stacked and spaced apart from each other to form a stacked electrode assembly 2. For another example, the anode plates 21 and the cathode plates 22 are wound around each other to form a wound electrode assembly 2, but the embodiments of the present application are not limited thereto.

[0063] It should be understood that in the embodiment of the present application, a separator 23 may be further provided between the anode electrode piece 21 and the cathode electrode piece 22 to achieve electrical isolation between the anode electrode piece 21 and the cathode electrode piece 22. An electrolyte is also provided in the battery cell, and the electrolyte acts as a carrier of metal ions in the battery cell, enabling the battery cell to operate by relying on the movement of metal ions between the cathode electrode piece 22 and the anode electrode piece 21.

[0064] The method 100 of the embodiment of the present application can be used for lithium deposition analysis of the electrode assembly 2. Considering the location where the lithium deposition phenomenon occurs, the following description is mainly based on the main body of the electrode assembly 2 as an example.

[0065] It should be understood that, as shown in Figures 2 to 3, regardless of the type of electrode assembly 2, according to the structural characteristics of the electrode assembly 2, the electrode assembly 2 can be regarded as including a plurality of electrode sheet modules 201 stacked on each other, wherein each electrode sheet module 201 includes a cathode current collector 221, a cathode active material layer 222, a separator 23, an anode active material layer 212 and an anode current collector 211 along the stacking direction, wherein the cathode active material layer 222 and the anode active material layer 212 are located between the cathode current collector 221 and the anode current collector 211. Therefore, the RVE model of the embodiment of the present application can include the electrode sheet module 201. For example, relevant parameters of at least a portion of the region of the electrode sheet module 201 of the electrode assembly 2 can be input to establish the RVE model of the electrode assembly 2, and then lithium deposition analysis can be performed on various types of electrode assemblies 2. Compared with the full-scale model, the model can be simplified and the amount of calculation can be reduced, while the accuracy of the numerical simulation can be guaranteed and the simulation efficiency can be improved.

[0066] It should be understood that the shape of the wound electrode assembly 2 in the embodiment of the present application can be flexibly set according to actual application. For example, the cross-sectional shape of the wound electrode assembly 2 of different shapes as shown in Figure 2 may be different, for example, Figure 2 is a round shape, or the cross-sectional shape of the electrode assembly 2 may be circular, that is, the electrode assembly 2 as a whole is cylindrical, unlike Figure 2. The embodiment of the present application is not limited to this.

[0067] It should be understood that the wound electrode assembly 2 and the stacked electrode assembly of the shape shown in Figure 2 have in common that they both include a planar portion 25. Therefore, the modeling process of the planar portion 25 of the electrode assembly 2 shown in Figure 2 is also applicable to the stacked electrode assembly. Specifically, the planar portion 25 of the electrode assembly 2 may include at least one layer of anode electrode sheet 21, at least one layer of cathode electrode sheet 22, and a multi-layer separator 23, wherein the multi-layer separator 23 may include at least one first separator 231 and at least one second separator 232 at different positions. For example, as shown in Figures 2 to 3, the electrode sheet module 201 may include a planar area 251 located on the planar portion 25, and the planar portion 25 of the electrode assembly 2 may include a plurality of stacked planar areas 251. The planar area 251 is a relatively flat planar area of ​​the electrode assembly 2 and can be used to form the end face with the largest area of ​​the electrode assembly 2.

[0068] The difference between the wound electrode assembly 2 of the shape shown in Figure 2 and the stacked electrode assembly is that the wound electrode assembly 2 also includes a bend 26, which can be used to connect the multi-layer structure included in the planar portion 25. Therefore, the modeling process of the bend 26 of the electrode assembly 2 is not applicable to the stacked electrode assembly. Specifically, as shown in Figures 2 and 3, the electrode assembly 2 may include two bends 26 located on both sides of the planar portion 25, wherein, for any one of the bends 26, the bend 26 may include at least one layer of anode electrode sheet 21, at least one layer of cathode electrode sheet 22 and a multi-layer separator 23, wherein the multi-layer separator 23 may include at least one first separator 231 and at least one second separator 232 at different positions. For example, the electrode module 201 may include a bend area 261 located at the bend 26, and the electrode module 201 may include two bend areas 261 connected to the planar region 251. For ease of explanation, the embodiment of the present application takes any one bending area 261 included in the electrode module 201 as an example. The bending area 261 is roughly arc-shaped and can be used to form a side end surface with a smaller area of ​​the electrode assembly 2.

[0069] It should be understood that, unlike stacked electrode assemblies, cylindrical electrode assemblies and the wound electrode assembly 2 shown in FIG2 share the same feature of including a bent portion 26. Therefore, the modeling process for the bent portion 26 of the electrode assembly 2 shown in FIG2 is also applicable to cylindrical electrode assemblies. However, the difference between a cylindrical electrode assembly and the wound electrode assembly 2 shown in FIG2 is that the wound electrode assembly 2 shown in FIG2 includes a planar portion 25, while the cylindrical electrode assembly does not. Therefore, the modeling process for the planar portion 25 is not applicable to cylindrical electrode assemblies.

[0070] Therefore, the following will take the electrode assembly 2 shown in FIG. 2 as an example to describe the method 100 of the embodiment of the present application from the perspectives of the planar portion 25 and the bent portion 26 .

[0071] Optionally, the embodiment of the present application mainly takes the RVE model including at least a partial area of ​​the pole piece module 201 as an example. For example, for a stacked electrode assembly, the RVE model includes the planar area 251 of the pole piece module 201, and for a cylindrical wound electrode assembly, the RVE model may include the bending area 261 of the pole piece module 201; in addition, for other types of electrode assemblies, the RVE model may also include other parts that are not limited here. The RVE model of the embodiment of the present application can be established based on a traditional quasi-two-dimensional (Pseudo-2-Dimensional, P2D) model. Specifically, step 110 of the method 100 of the embodiment of the present application may specifically include: referring to the P2D model, determining at least one control equation for at least a partial area of ​​the pole piece module 201; and establishing an RVE model of the electrode assembly 2 based on the at least one control equation.

[0072] Optionally, as an embodiment, for the solid-phase diffusion part, according to Fick's law, the molar flux caused by diffusion is proportional to the concentration gradient, and the rate of change of the concentration at a certain point in space is proportional to the spatial second-order derivative of the concentration, thereby determining at least one control equation satisfied by the electrode module 201. For example, taking the anode active material layer 212 of the electrode module 201 of the present application as an example, assuming that the solid-phase particles of the anode active material layer 212 on the surface of the anode electrode 21 are spherical particles, for example, the anode active material layer 212 on the surface of the anode electrode 21 has a large amount of graphite, assuming that the graphite is a spherical particle, with the center of the sphere as the coordinate origin, determining at least one control equation of the electrode module 201 may include the following formula (1):

[0073] Among them, c s is the amount of solid-phase lithium insertion, D s is the solid phase diffusion coefficient, r is the position in the radial direction of the solid phase particle, j is the surface current density of the solid phase particle, F is the Faraday constant, R is the radius of the solid phase particle, and t is time.

[0074] Similarly, by replacing the relevant parameters, formula (1) can also be used as the control equation of the cathode active material layer 222 of the cathode electrode 22 in the electrode module 201 to perform numerical simulation of the cathode active material layer 222 of the cathode electrode 22 in the electrode module 201. The embodiments of the present application are not limited to this.

[0075] Alternatively, as another embodiment, for the liquid phase diffusion process, the at least one control equation satisfied by the electrode module 201 can also be determined based on Fick's law, taking into account the diffusion process of lithium ions in the thickness direction of the anode active material layer 212 of the anode electrode 21, and the electron migration process that satisfies the electron conservation law. For example, referring to formula (1), also taking the anode active material layer 212 of the anode electrode 21 of the electrode module 201 of the present application as an example, the at least one control equation of the electrode module 201 can include the following formula (2):

[0076] Among them, ε l is the porosity of the corresponding area of ​​the anode active material layer 212 of the anode electrode 21, c l is the lithium ion concentration in the liquid phase component, x is the thickness direction coordinate of the anode active material layer 212, D eff,l is the effective liquid phase diffusion coefficient, t + is the ion migration number of lithium ions in the electrolyte, a is the specific surface area of ​​the solid particles, j(x, t) is the lithium ion flux in different regions of the anode active material layer 212, L is the total thickness of the anode active material layer 212, and the meanings of other parameters refer to the above formula (1).

[0077] Similarly, by replacing the relevant parameters, formula (2) can also be used as the control equation of the cathode active material layer 222 of the cathode electrode 22 and the isolation membrane 23 located between the cathode electrode 22 and the anode electrode 21, so as to perform numerical simulation of the cathode active material layer 222 and the isolation membrane 23 of the cathode electrode 22 of the electrode module 201. The embodiments of the present application are not limited to this.

[0078] Alternatively, as another embodiment, the solid-phase potential and the liquid-phase potential can be calculated and determined by Ohm's law and Kirchhoff's law to determine the potential and current at each position in the battery cell, thereby determining at least one control equation satisfied by the electrode module 201. For example, referring to the above formulas, the control equation of the electrode module 201 can include the following formula (3):

[0079] Among them, σ s,eff and σ l,eff are the effective conductivity of the solid phase and liquid phase respectively; Φ s and Φ lwhere is the solid-phase potential and liquid-phase potential, respectively; i1(x, t) is the solid-phase current density; i2(x, t) is the liquid-phase current density; R is the gas constant; T is the temperature, which can be set to a specific value based on the numerical simulation requirements, or a default temperature value can be set; the meanings of other parameters can be referred to in the above formulas. The boundary conditions in formula (3) indicate that the anode electrode 21 is grounded and the potential of the cathode electrode 22 is equal to the potential Ecell of the entire battery cell.

[0080] Alternatively, as another embodiment, the surface current density of the anode electrode 21 and / or the cathode electrode 22 can be obtained by the Butler-Volmer equation. For example, referring to the above formulas, taking the electrode module 201 of the present application as an example, at least one control equation thereof can include the following formula (4):

[0081] Among them, for the anode electrode 21 in the electrode module 201, c s,max is the maximum density of lithium ions that can be accommodated in the particles of the anode active material layer 212 on the surface of the anode electrode 21. For example, taking the graphite of the anode active material layer 212 on the surface of the anode electrode 21 as an example, c s,max It can represent the maximum density of lithium ions that can be accommodated in graphite particles; c s,surf is the lithium ion density on the surface of the particles of the anode active material layer 212 on the surface of the anode electrode 21. For example, still taking the graphite of the anode active material layer 212 on the surface of the anode electrode 21 as an example, c s,surf It can represent the lithium ion density on the surface of graphite particles. i0 is the exchange current density, K a and K c are the reaction rate constants of the anode electrode 21 and the cathode electrode 22, respectively, a and α c are the transfer coefficients of the anode electrode 21 and the cathode electrode 22 respectively, η is the electrode reaction overpotential, and the meanings of other parameters can refer to the above formulas.

[0082] Similarly, by replacing relevant parameters, formula (4) can also be used as the control equation of the cathode pole piece 22 of the pole piece module 201 to perform numerical simulation on the cathode pole piece 22 part included in the pole piece module 201. The embodiments of the present application are not limited to this.

[0083] It should be understood that the aforementioned governing equations can be used for numerical simulations of various types of electrode assemblies 2. For example, they can be used for numerical simulations of the planar portion 25 and / or the bent portion 26 of the electrode assembly 2. However, different governing equations exist for different types of electrode assemblies 2. The following describes the modeling process of the planar region 251 located on the planar portion 25 of the electrode module 201, taking the planar region 251 included in the electrode module 201 as an example.

[0084] In the embodiment of the present application, the electrode module 201 includes a planar region 251, which is used to form the end face with the largest area of ​​the electrode assembly 2. Step 110 of method 100 may specifically include: determining parameters of the planar region 251 to establish an RVE model, wherein the RVE model includes the planar region 251. Specifically, considering that the electrode module 201 of a stacked electrode assembly 2 or a wound electrode assembly 2 as shown in FIG. 2 includes the planar region 251, the RVE model established based on the parameters of the planar region 251 can be applied to the numerical simulation of different types of electrode assemblies 2.

[0085] Optionally, the parameters of the planar area 251 can be flexibly set according to actual applications. For example, determining the parameters of the planar area 251 in an embodiment of the present application may include: establishing a geometric model of the planar area 251 included in the electrode module 201 based on the actual size of the electrode assembly 2, and the parameters of the planar area 251 may include the geometric model of the planar area 251. For example, the geometric model of the planar area 251 included in the electrode module 201 may be the electrode module 201 shown in Figure 3, that is, the geometric model of the planar area 251 established is similar to the actual electrode assembly 2 and is flat.

[0086] For another example, the parameters of the planar region 251 determined in the embodiment of the present application may also include: establishing a control equation for the planar region 251 of the electrode module 201 based on the change in the internal pore structure of the anode electrode 21 and / or the cathode electrode 22 caused by stress, wherein the parameters of the planar region 251 include the control equation for the planar region 251. Specifically, considering that the direct effect of stress on the electrochemical parameters of the electrode is often reflected in the change in the internal pore structure of the electrode caused by stress, thereby affecting the change in electrochemical kinetic parameters, the electrode may include the anode electrode 21 and / or the cathode electrode 22. Therefore, the control equation for the planar region 251 of the electrode module 201 can be determined based on the effect of stress on the electrochemical parameters of the electrode module 201. For example, the control equation for the planar region 251 may include the following formula (5):

[0087] Wherein, ε, σ and YM are strain, corresponding stress and Young's modulus generated by stress in each region of the plane region 251, respectively. l0 is the initial porosity of the corresponding area of ​​the plane area 251, ε l is the porosity of the corresponding area of ​​the plane area 251 after compression, (·) eff is the effective electrochemical parameter, (·) is the initial electrochemical parameter, and Brug is the Bergmann coefficient, which is used to describe the tortuosity information of the internal microstructure of the electrode pores.

[0088] It should be understood that by setting different values ​​for each parameter, formula (5) can be used as a control equation for the cathode electrode 22 portion, the anode electrode 21 portion, and the isolation membrane 23 portion of the electrode module 201 located in the plane area 251 in the RVE model, so as to perform numerical simulation of the cathode electrode 22, the anode electrode 21, and the isolation membrane 23 included in the electrode module 201 located in the plane area 251, but the embodiments of the present application are not limited to this.

[0089] It should be understood that the above formula (5) often does not consider the effect of stress on the wetting effect. However, during the actual charge and discharge process of the battery cell, as the material on the electrode surface expands or contracts due to stress, the corresponding electrolyte will be squeezed out or reflow. Therefore, the impact of this factor on the lithium deposition process must also be considered.

[0090] Optionally, determining the parameters of the planar region 251 in the embodiment of the present application may include establishing a governing equation for the planar region 251 based on the influence of stress on the wetting effect of the planar region 251, wherein the parameters of the planar region 251 include the governing equation for the planar region 251. By considering the influence of stress on the wetting effect, the RVE model can be made to more closely resemble the changes in the electrode assembly 2 during the charge and discharge process during actual battery cell use, resulting in more accurate simulation results.

[0091] Specifically, based on the effect of stress on the wetting effect of planar region 251, establishing a governing equation for planar region 251 can specifically include: determining the porosity of different regions of planar region 251 based on the stress distribution in different regions of planar region 251; and determining the electrolyte seepage velocity in planar region 251 based on the porosity of different regions of planar region 251 based on Darcy's law. The governing equation for planar region 251 includes the seepage velocity. Since stress can cause the material on the electrode surface to expand or contract, stress affects the porosity of different regions of the electrode. According to Darcy's law, porosity is proportional to the electrolyte seepage velocity in the corresponding region. Therefore, an equation for the seepage velocity in the corresponding region can be obtained, and this equation can be used to simulate and calculate the effect of stress on the wetting effect, making the RVE model calculation results more accurate.

[0092] For example, according to practical applications, the control equation of the plane region 251 may include the following formula (6):

[0093] Wherein, u1 represents the seepage velocity of the plane area 251, and the sign of u1 represents the direction of the seepage velocity, and the absolute value of u1 represents the magnitude of the seepage velocity of the plane area 251; K represents the permeability, μ represents the dynamic viscosity of the electrolyte, Δp represents the interface pressure difference, ρ represents the density of the electrolyte, g represents the acceleration of gravity, and ε l1represents the porosity of the plane region 251, and the porosity ε of the plane region 251 l1 It is proportional to the absolute value of the seepage velocity u1 in the plane area 251; Rc1 represents the equivalent pore radius in the plane area 251. l1 According to the ε in formula (5) l Calculation is performed, that is, within the plane area 251, ε l1 Equal to ε l .

[0094] It should be understood that by setting different values ​​for each parameter, formula (6) can be used as a control equation for the cathode electrode 22 portion, the anode electrode 21 portion, and the isolation membrane 23 portion of the electrode module 201 located in the planar area 251 in the RVE model, so as to perform numerical simulation of the cathode electrode 22, the anode electrode 21, and the isolation membrane 23 included in the electrode module 201 located in the planar area 251. The embodiments of the present application are not limited to this.

[0095] The above mainly introduces the control equations of the planar area 251 of the electrode module 201, which can be used for the numerical simulation process of the wound electrode assembly 2 and the stacked electrode assembly as shown in Figure 2. It should be understood that in order to distinguish between the wound electrode assembly 2 and the stacked electrode assembly, the method 100 may also include: determining whether the established RVE model of the electrode assembly 2 needs to include the bend 26. For example, it can be determined whether the electrode assembly 2 is a wound electrode assembly 2 based on the type of electrode assembly 2 to be simulated, or based on customer needs, wherein the wound electrode assembly 2 can be an electrode assembly 2 of the shape shown in Figure 2, or it can also be a cylindrical electrode assembly, and the embodiments of the present application are not limited to this.

[0096] Furthermore, method 100 may further include: if simulation of a wound electrode assembly 2 is required, determining whether to establish an RVE model for the electrode assembly 2 including the bend 26 based on the numerical simulation requirements. For example, for the wound electrode assembly 2 shown in Figure 2, the user may determine whether to consider the difference between the bend 26 and the planar portion 25 based on the simulation requirements. If not, the simulation process for the planar portion 25 can be applied to the bend 26; if it is considered, the RVE model can be established based on the bend 26. For another example, if a cylindrical electrode assembly does not include a planar portion 25, a model of the bend 26 can be used for the numerical simulation.

[0097] In the embodiment of the present application, the need to perform numerical simulation on the bending portion 26 is used as an example for introduction. Specifically, the pole piece module 201 is still taken as an example. The electrode assembly 2 is a wound electrode assembly 2, and the pole piece module 201 includes a bending area 261, wherein the bending area 261 is located in the bending portion 26, and the bending area 261 is used to form a curved surface of the electrode assembly 2. For example, Figure 4 shows a cross-sectional schematic diagram of the bending portion 26 of the embodiment of the present application. For example, the bending portion 26 shown in Figure 4 can be the right side bending portion 26 of the electrode assembly 2 as shown in Figure 2, and the bending portion 26 can include the bending area 261 of the pole piece module 201, that is, the bending portion 26 can be regarded as the bending areas 261 of multiple pole piece modules 201 stacked on each other, wherein each bending area 261 intersects with the plane area 251 of the pole piece module 201 and is located in a different plane. For another example, the bending portion 26 shown in Figure 4 can also be half of the cylindrical electrode assembly 2, and the embodiment of the present application is not limited to this.

[0098] Optionally, step 110 of method 100 may further include determining parameters of the bend region 261 to establish an RVE model, where the RVE model includes the planar region 251 and the bend region 261. Specifically, when the parameters of the bend region 261 are considered in the RVE model, the RVE model can be used for a wound electrode assembly 2 having a bend 26 to reflect the difference between the bend region 261 and the planar region 251, thereby making the RVE model more widely applicable and the calculation results more accurate.

[0099] Optionally, the parameters of the bending region 261 can be flexibly set according to actual applications. For example, determining the parameters of the bending region 261 in an embodiment of the present application may include: establishing a geometric model of the bending region 261 based on the actual size of the electrode assembly 2, and the parameters of the bending region 261 may include the geometric model of the bending region 261. For example, the geometric model of the bending region 261 included in the electrode module 201 can be similar to the actual electrode assembly 2, that is, the geometric model of the bending region 261 established is similar to the bending portion 26 shown in Figure 4, and has a curvature.

[0100] For another example, for the sake of modeling convenience, the geometric model of the bending area 261 in the RVE model of the embodiment of the present application may not match the shape of the actual electrode assembly 2, that is, it is not necessary to separately establish a geometric model of the bending area 261 with the same curvature as the actual wound electrode assembly 2, but to establish a geometric model of the bending area 261 of the pole piece module 201 as shown in Figure 3, that is, the pole piece module 201 shown in Figure 3 can also be used as the geometric model of the bending area 261, and the difference between the bending area 261 and the plane area 251 can be reflected by adjusting specific parameters.

[0101] It should be understood that by adjusting the parameter values, the control equations (1) to (5) for the planar region 251 described above can also be applied to the bend region 261, and will not be repeated here. The following, in conjunction with the accompanying drawings, details the control equations for the bend region 261 that differ from those for the planar region 251, focusing on the key differences between the bend region 261 and the planar region 251.

[0102] Optionally, the parameters of the bending region 261 determined in the embodiment of the present application may specifically include: establishing a first control equation for the bending region 261 based on the influence of stress on the wetting effect of the bending region 261, and the parameters of the bending region 261 include the first control equation for the bending region 261. Due to the geometric structure of the bending region 261, there is a gap between the anode electrode 21 and the cathode electrode 22, which will lead to insufficient electrolyte infiltration of the anode and cathode electrodes on both sides of the isolation membrane 23, thereby causing the electrochemical reaction kinetics to deteriorate. Moreover, similar to the planar region 251, for the bending region 261, during the actual charge and discharge process of the battery cell, as the material on the surface of the electrode sheet expands or contracts due to stress, the corresponding electrolyte will be squeezed out or reflux. Therefore, by considering the influence of stress on the wetting effect, the RVE model can be made closer to the changes in the electrode assembly 2 during the charge and discharge process of the actual battery cell, making the simulation results more accurate.

[0103] Specifically, based on the effect of stress on the wetting effect of the bend region 261, establishing a first control equation for the bend region 261 may specifically include: determining the porosity of different regions of the bend region 261 based on the stress distribution in different regions of the bend region 261; and determining the seepage velocity of the electrolyte in the bend region 261 based on the porosity of different regions of the bend region 261 based on Darcy's law. The control equation for the bend region 261 includes the seepage velocity of the electrolyte in the bend region 261. Since stress can cause the material on the surface of the electrode to expand or contract, stress will affect the porosity of different regions of the electrode. According to Darcy's law, the porosity is proportional to the seepage velocity of the electrolyte in the corresponding region. Therefore, an equation for the seepage velocity of the corresponding region can be obtained, and the effect of stress on the wetting effect can be simulated and calculated using this equation, making the RVE model calculation results more accurate.

[0104] For example, according to practical applications, the first control equation of the bending region 261 may include the following formula (7):

[0105] Wherein, u2 represents the seepage velocity in the bending area 261, and the sign of u2 represents the direction of the seepage velocity, and the absolute value of u2 represents the magnitude of the seepage velocity in the bending area 261; K represents the permeability, μ represents the dynamic viscosity of the electrolyte, Δp represents the interface pressure difference, ρ represents the density of the electrolyte, g represents the acceleration of gravity, and εl2 represents the porosity of the bending region 261, and the porosity ε of the bending region 261 l2 Rc2 is proportional to the absolute value of the seepage velocity u2 in the bending area 261, and represents the pore equivalent radius of the bending area 261. l2 According to the ε in formula (5) l Calculation is performed by replacing the parameters of the plane area 251 in formula (5) with the parameters corresponding to the bending area 261, and then calculating the ε of the bending area 261 l , ε l2 Equal to ε of the bending area 261 l .

[0106] It should be understood that by setting different values ​​for each parameter, formula (7) can be used as a control equation for the cathode electrode 22 portion, the anode electrode 21 portion, and the isolation membrane 23 portion of the electrode module 201 located in the bending area 261 in the RVE model, so as to perform numerical simulation of the cathode electrode 22, the anode electrode 21, and the isolation membrane 23 included in the electrode module 201 located in the bending area 261. The embodiments of the present application are not limited to this.

[0107] It should be understood that compared to the flat portion 25, considering that the pole piece will bend at the bending portion 26, the same pole piece will form a concave surface and a convex surface at the bending portion 26. In addition, there are gaps between the pole pieces. These will affect the capacity balance (cell balance, CB) value of the battery cell, and thus affect the thermodynamic parameters of some areas.

[0108] Optionally, determining the parameters of the bending region 261 may further include: establishing a second control equation for the bending region 261 based on the effect of the bending region 261 on the CB value of the electrode assembly 2, wherein the parameters of the bending region 261 include the second control equation for the bending region 261. Therefore, the second control equation for the bending region 261 can simulate the effect of the bending region 261 on the CB value of the electrode assembly 2. In particular, when the RVE model uses the electrode module 201 shown in Figure 3 to geometrically model the bending portion 26, the second control equation can be used to simulate the concave and convex surfaces generated by the bending of each electrode in the bending portion 26, as well as the gap between the cathode and anode electrodes, to distinguish them from the planar portion 25, thereby increasing the accuracy of the RVE model.

[0109] Optionally, according to the influence of the bending region 261 on the CB value of the electrode assembly 2, the second control equation for establishing the bending region 261 in the embodiment of the present application may specifically include: determining the relationship between the CB value of the bending region 261 and the preset CB value based on the total thickness of the electrode module 201 in the bending region 261, the distance between the cathode active material layer 222 and the anode active material layer 212 in the bending region 261, and the number of winding layers of the electrode assembly 2, so as to establish the second control equation, the second control equation including the relationship between the CB value of the bending region and the preset CB value. In this way, by combining the characteristics of the bending region 261 and reasonably adjusting the CB value of the bending region 261, the RVE model can be made more accurate and the numerical simulation effect more accurate.

[0110] For example, according to practical applications, the second control equation of the bending region 261 may include the following formula (8):

[0111] 3 and 4 , it is assumed that the bending portion 26 shown in FIG4 is the bending portion 26 included in the actual electrode assembly 2, and the electrode module 201 shown in FIG3 is the geometric model of the bending area 261 established in the RVE model, wherein the electrode module 201 shown in FIG3 is located at the outermost side of the bending portion 26 shown in FIG4 , and CB represents the CB value of the electrode assembly 2 at the bending portion 26; L1 is the arc length of the anode active material layer 212 of the anode electrode sheet 21 in the electrode module 201 in the bending area 261; L2 is the arc length of the cathode active material layer 222 of the cathode electrode sheet 22 in the electrode module 201 in the bending area 261; N represents the number of winding layers of the simulated electrode assembly 2, L gap CB represents the gap length between the cathode active material layer 222 and the anode active material layer 212 in the bending region 261, and d represents the total thickness of the electrode module 201 in the bending region 261, that is, d represents the total thickness between the anode current collector 211 and the cathode current collector 221 of the anode electrode 21 in the bending region 261. design It represents the preset CB value of the electrode assembly 2 during the initial design.

[0112] For the second formula in formula (8), c s,max The maximum density of lithium ions that can be accommodated in the particles of the anode active material layer 212 on the surface of the anode electrode 21 or the cathode active material layer 222 on the surface of the cathode electrode 22. For example, taking the graphite of the anode active material layer 212 on the surface of the anode electrode 21 as an example, c s,max It can represent the maximum density of lithium ions that can be accommodated in graphite particles; and c s,max,effThe maximum density of lithium ions that can be accommodated in the particles of the anode active material layer 212 on the surface of the anode electrode 21 or the cathode active material layer 222 on the surface of the cathode electrode 22 after taking into account the CB value conversion of the bent portion 26. s,max,eff The value can be substituted into the above formula (4) s,max value to obtain the control equation (4) of the bending portion 26.

[0113] Optionally, in addition to the above-mentioned control equations and parameters, other parameters may be input to establish the RVE model of the electrode assembly 2. For example, the materials of the anode electrode piece 21, cathode electrode piece 22, and separator 23 of the electrode assembly 2 may be input. For another example, the number of cycles of the numerical simulation may be input. For example, the default number of cycles may be set to one, i.e., the simulation process ends after one charge and discharge. The embodiments of the present application are not limited to this.

[0114] In this embodiment of the present application, in step 120, a numerical simulation of the electrode assembly 2 can be performed based on the established RVE model to analyze the lithium deposition of the electrode assembly 2. Specifically, after inputting relevant data parameters, the overall anode potential can be estimated. Based on the anode potential, whether lithium deposition has occurred can be determined, and further, the severity of the lithium deposition can be determined.

[0115] Optionally, determining whether lithium deposition occurs based on the anode potential may specifically include: if the estimated anode potential is greater than zero, determining that lithium deposition does not occur in the electrode assembly 2; if the estimated anode potential is less than or equal to zero, determining that lithium deposition occurs in the electrode assembly 2.

[0116] Therefore, in the method 100 of the embodiment of the present application, the electrode assembly 2 is numerically simulated by using the RVE model of the electrode assembly 2 to analyze the lithium deposition of the electrode assembly 2. Unlike the full-scale model, the RVE model used in the embodiment of the present application includes a part of the electrode assembly 2, for example, the electrode module 201 of the electrode assembly 2, and the electrode module 201 includes, in sequence: a cathode current collector 221, a cathode active material layer 222, a separator 23, an anode active material layer 212, and an anode current collector 211, that is, the electrode assembly 2 can be regarded as a structure formed by the cycle of the electrode module 201. In this way, by inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the occupied resources can be reduced while ensuring the accuracy of the calculation; moreover, the same RVE model can be applied to multiple types of electrode assemblies 2, that is, different types of electrode assemblies 2 can be simulated, avoiding the process of repeated re-modeling, simplifying the calculation and modeling process, and improving the efficiency of the simulation.

[0117] In addition, the RVE model of the present application takes the bending portion 26 into consideration, and can be used for the numerical simulation of the wound electrode assembly 2 having the bending portion 26 to reflect the difference between the bending portion 26 and the planar portion 25, making the RVE model more widely applicable and the calculation results more accurate.

[0118] Figure 5 shows a schematic flow chart of a method 300 for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application. As shown in Figure 5, the method 300 may include: step 310, establishing a third control equation based on the effect of stress on the wetting effect of the electrode sheet of the electrode assembly; step 320, establishing a simulation model of the electrode assembly based on the parameters of the electrode assembly, wherein the parameters of the electrode assembly include the third control equation; and step 330, performing a numerical simulation of the electrode assembly based on the simulation model to analyze the lithium deposition of the electrode assembly.

[0119] During the actual charge and discharge process of a battery cell, as stress causes the material on the electrode surface to expand or contract, the corresponding electrolyte will be squeezed out or reflux, which also has a significant impact on the lithium deposition process. Therefore, in method 300 of the embodiment of the present application, the effect of stress on the wetting effect is considered when establishing the simulation model of the electrode assembly. This can make the electrode assembly model more closely resemble the changes in the electrode assembly during the charge and discharge process during the actual use of the battery cell, making the simulation results more accurate.

[0120] It should be understood that step 310 of method 300 of the embodiment of the present application may specifically include: determining the porosity of different regions of the electrode assembly's electrode sheet based on the stress distribution of different regions of the electrode assembly's electrode sheet; determining the electrolyte seepage velocity in the electrode assembly's electrode sheet based on the porosity of different regions of the electrode assembly's electrode sheet based on Darcy's law, and the third control equation includes the electrolyte seepage velocity in the electrode assembly's electrode sheet. Since stress may cause the material on the surface of each electrode sheet of the electrode assembly to expand or contract, stress will affect the porosity of different regions of the electrode sheet; and according to Darcy's law, the porosity is proportional to the electrolyte seepage velocity in the corresponding region. Therefore, an equation for the seepage velocity in the corresponding region can be obtained. This third equation can include the electrolyte seepage velocity in the electrode assembly's electrode sheet. By simulating and calculating the effect of stress on the wetting effect through this third control equation, the calculation results of the electrode assembly model can be made more accurate.

[0121] The method 300 of the embodiment of the present application can be applied to the numerical simulation process of various types of electrode assemblies, and can also be used to establish different numerical models of electrode assemblies. For example, the method 300 can be applied to a stacked or wound electrode assembly. As another example, the method 300 can be applied to the full-scale modeling process of an electrode assembly, that is, the simulation model of the electrode assembly can include a full-scale simulation model of the electrode assembly; alternatively, the method 300 can also be applied to an RVE model of an electrode assembly.

[0122] For ease of explanation, the following mainly uses the RVE model as an example for explanation, but the embodiments of the present application are not limited to this. Specifically, step 320 of the embodiment of the present application may specifically include: establishing an RVE model of the electrode assembly based on the parameters of the electrode assembly, the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes in sequence: a cathode current collector, a cathode active material layer, an isolation membrane, an anode active material layer, and an anode current collector. Unlike the full-size model, the RVE model used in the embodiment of the present application does not require the establishment of the overall structure of the electrode assembly. By inputting appropriate feature information, the amount of calculation can be greatly reduced, the model can be simplified, and the occupied resources can be reduced while ensuring the accuracy of the calculation.

[0123] It should be understood that when applied to the RVE model, method 300 is similar to method 100 described above and is applicable to the relevant description of method 100 described above. For the sake of brevity, this description is not repeated here. For example, method 300 can be applied to the numerical simulation of various types of electrode assemblies, such as wound electrode assemblies or stacked electrode assemblies, and is applicable to the relevant description of method 100 described above with respect to Figures 2 to 4.

[0124] In the embodiment of the present application, for the sake of ease of description, the wound electrode assembly 2 shown in Figure 2 is still taken as an example. First, for the planar portion 26, the pole piece module 201 includes a planar area 251, and the planar area 251 is used to form the end face with the largest area of ​​the electrode assembly 2. Step 310 in the method 300 may specifically include: establishing a control equation for the planar area 251 based on the influence of stress on the wetting effect of the planar area 251, and the third control equation includes the control equation for the planar area 251. Specifically, considering that the pole piece module 201 of the stacked or wound electrode assembly 2 as shown in Figure 2 includes a planar area 251, the RVE model established according to the parameters of the planar area 251 can be applied to the numerical simulation of different types of electrode assemblies 2.

[0125] It should be understood that the process of establishing the control equation for the plane region 251 included in the third control equation is similar to the corresponding steps in the above method 100. For example, a control equation such as formula (6) can be established. For the sake of brevity, it will not be repeated here.

[0126] In an embodiment of the present application, similar to method 100, the electrode assembly 2 may further include a bending portion 26. Specifically, the electrode assembly 2 is a wound electrode assembly 2, and the electrode module 201 includes a bending area 261, wherein the bending area 261 is located at the bending portion 26, and the bending area 261 is used to form a curved surface of the electrode assembly 2. Step 310 in method 300 may further specifically include: establishing a first control equation for the bending area 261 based on the influence of stress on the wetting effect of the bending area 261, and the third control equation includes the first control equation. Specifically, when the parameters of the bending area 261 are considered in the RVE model, the RVE model can be used for a wound electrode assembly 2 having a bending portion 26 to reflect the difference between the bending area 261 and the plane area 251, so that the RVE model is more widely used and the calculation results are more accurate.

[0127] It should be understood that the process of establishing the first control equation included in the third control equation is similar to the corresponding steps in method 100 above, and for the sake of brevity, it is not repeated here. For example, the method of establishing the first control equation in method 100 can be referred to to establish a control equation such as formula (7).

[0128] In the embodiment of the present application, according to the description of method 100 above, compared with the planar portion 25, considering that the pole piece will bend at the bending portion 26, the same pole piece will form a concave surface and a convex surface at the bending portion 26. In addition, there are gaps between the pole pieces, which will affect the CB value of the battery cell and thus affect the thermodynamic parameters of some areas.

[0129] Therefore, the method 300 may further include: establishing a second control equation for the bend region 261 based on the effect of the bend region 261 on the preset CB value of the electrode assembly 2, wherein the parameters of the electrode assembly 2 include the second control equation. Therefore, the second control equation for the bend region 261 can simulate the effect of the bend region 261 on the CB value of the electrode assembly 2. In particular, when the RVE model uses the electrode module 201 shown in Figure 3 to geometrically model the bend portion 26, the second control equation can simulate the concave and convex surfaces generated by the bending of each electrode piece in the bend portion 26, as well as the gap between the cathode and anode electrodes, to distinguish them from the planar portion 25, thereby increasing the accuracy of the RVE model.

[0130] It should be understood that the process of establishing the second control equation in method 300 is similar to the process of establishing the second control equation in method 100 , and for the sake of brevity, it will not be repeated.

[0131] For example, in the method 300, based on the influence of the bending region 261 on the preset CB value of the electrode assembly 2, establishing the second control equation of the bending region 261 can specifically include: determining the relationship between the CB value of the bending region 261 and the preset CB value based on the total thickness of the electrode module 201 in the bending region 261, the distance between the cathode active material layer 222 and the anode active material layer 212 in the bending region 261, and the number of winding layers of the electrode assembly 2, so as to establish the second control equation, which includes the relationship between the CB value of the bending region 261 and the preset CB value. In this way, combining the characteristics of the bending region 261 and reasonably adjusting the CB value of the bending region 261 can make the RVE model more accurate and the numerical simulation effect more accurate. For example, the second control equation can include the above formula (8), but the embodiments of the present application are not limited to this.

[0132] Figure 6 shows a schematic flow chart of a method 400 for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application. As shown in Figure 6, the method 400 includes: step 410, establishing a simulation model of the electrode assembly based on the parameters of the bend of the wound electrode assembly, the simulation model including the bend; step 420, performing a numerical simulation of the electrode assembly based on the simulation model to analyze the lithium deposition of the electrode assembly.

[0133] Therefore, considering that the difference between a wound electrode assembly and a stacked electrode assembly is that the wound electrode assembly has a bending portion, the method 400 of the embodiment of the present application establishes a simulation model of the electrode assembly according to the parameters of the bending portion, targeting the structural specificity of the bending portion included in the wound electrode assembly. This enables the simulation model to be used for simulating the wound electrode assembly more accurately and the calculation results to be more accurate.

[0134] The method 400 of the embodiment of the present application can be applied to the numerical simulation process of wound electrode assemblies of various shapes, and can also be used to establish different numerical models of electrode assemblies. For example, the method 400 can be applied to any electrode assembly including a bend, such as a cylindrical electrode assembly or an electrode assembly having a shape as shown in FIG2 . For another example, the method 400 can be applied to the full-scale modeling process of the electrode assembly, that is, the simulation model of the electrode assembly can include a full-scale simulation model of the electrode assembly; alternatively, the method 400 can also be applied to the RVE model of the electrode assembly.

[0135] It should be understood that when method 400 is applied to an RVE model, the steps are similar to those of method 100 described above and are applicable to the relevant description of method 100. For the sake of brevity, detailed description is omitted here. For example, method 400 can be applied to the description of bend 26 in Figures 2 to 4 in method 100. The following description will primarily use the bend 26 shown in Figures 2 to 4 as an example.

[0136] It should be understood that the parameters of the bending portion 26 of the embodiment of the present application can be flexibly set according to the actual application. For example, the method 400 of the embodiment of the present application may include: establishing a geometric model of at least part of the bending portion 26 according to the actual size of the electrode assembly 2, and the parameters of the bending portion 26 may include the geometric model of at least part of the bending portion 26. Specifically, if a full-size model of the electrode assembly 2 is established, the overall geometric model of the bending portion 26 can be established according to the actual size of the electrode assembly 2. If an RVE model of the electrode assembly 2 is established, a geometric model of at least part of the bending portion 26 can be established. For example, a geometric model of the bending area 261 included in the pole piece module 201 and located at the bending portion 26 can be established. For example, the geometric model of the bending area 261 included in the pole piece module 201 can be similar to the actual electrode assembly 2, and be curved, that is, the geometric model of the bending area 261 established is similar to the bending portion 26 shown in Figure 4, and has a curvature.

[0137] For another example, for the sake of modeling convenience, the geometric model of the bending area 261 in the RVE model of the embodiment of the present application may not match the shape of the actual electrode assembly 2, that is, it is not necessary to separately establish a geometric model of the bending area 261 with the same curvature as the actual wound electrode assembly 2, but to establish a geometric model of the bending area 261 of the pole piece module 201 as shown in Figure 3, that is, the pole piece module 201 shown in Figure 3 can also be used as the geometric model of the bending area 261, and the difference between the bending area 261 and the plane area 251 can be reflected by adjusting specific parameters.

[0138] In the embodiment of the present application, no matter which simulation model is used, the method 400 may also include: establishing a first control equation of the bending portion 26 according to the influence of stress on the wetting effect of the bending portion 26, and the parameters of the bending portion 26 include the first control equation. Due to the geometric structure of the bending portion 26, there is a gap between the anode electrode 21 and the cathode electrode 22, which will lead to insufficient electrolyte infiltration of the anode and cathode electrodes on both sides of the isolation membrane 23, thereby causing the electrochemical reaction kinetics to deteriorate. Moreover, similar to the planar portion 25, for the bending portion 26, during the actual charge and discharge process of the battery cell, as the material on the surface of the electrode sheet expands or contracts due to stress, the corresponding electrolyte will be squeezed out or reflux. Therefore, by considering the influence of stress on the wetting effect, the simulation model of the electrode assembly 2 can be made closer to the changes in the electrode assembly 2 during the charge and discharge process of the actual battery cell, making the simulation results more accurate.

[0139] Specifically, the above-mentioned first control equation for the bend 26 based on the influence of stress on the wetting effect of the bend 26 can specifically include: determining the porosity of different regions of the bend 26 based on the stress distribution in different regions of the bend 26; and determining the seepage velocity of the electrolyte in the bend 26 based on the porosity of different regions of the bend 26 based on Darcy's law. The first control equation includes the seepage velocity of the electrolyte in the bend 26. Since stress can cause the material on the surface of the electrode piece to expand or contract, stress will affect the porosity of different regions of the electrode piece. According to Darcy's law, the porosity is proportional to the magnitude of the seepage velocity of the electrolyte in the corresponding region. Therefore, an equation for the seepage velocity of the corresponding region can be obtained, and the influence of stress on the wetting effect can be simulated and calculated using this equation, making the calculation results of the simulation model of the electrode assembly 2 more accurate.

[0140] For example, similar to the method 100 , by substituting relevant parameters of the bending portion 26 , the first control equation of the bending portion 26 may include formula (7), but the embodiment of the present application is not limited thereto.

[0141] It should be understood that, similar to method 100, if method 400 is used for the RVE model of the electrode assembly 2, the parameters of the bent portion 26 may also include other control equations. The following mainly uses the RVE model as an example for description.

[0142] Specifically, step 410 of method 400 may specifically include: establishing an RVE model of the electrode assembly 2 based on the parameters of the bend 26 of the wound electrode assembly 2, the RVE model including the electrode piece module 201 of the electrode assembly 2, and the electrode piece module 201 sequentially including: a cathode current collector 221, a cathode active material layer 222, a separator 23, an anode active material layer 212, and an anode current collector 211. Unlike a full-scale model, the RVE model used in the embodiment of the present application does not require the establishment of the overall structure of the electrode assembly 2. By inputting appropriate feature information, the amount of calculation can be greatly reduced while ensuring calculation accuracy, simplifying the model and reducing resource usage.

[0143] It should be understood that when the method 400 is applied to the RVE model, it is similar to the method 100 described above and is applicable to the relevant descriptions in the method 100 described above. For the sake of brevity, it will not be repeated here.

[0144] For example, step 410 of method 400 of an embodiment of the present application may specifically include: establishing an RVE model based on the parameters of the bending area 261 of the pole piece module 201, the bending area 261 being the area of ​​the pole piece module 201 located at the bending portion 26, and the parameters of the bending portion 26 include the parameters of the bending area 261.

[0145] For another example, in the embodiment of the present application, according to the description of method 100 above, compared with the planar portion 25, considering that the pole piece will bend at the bending portion 26, the same pole piece will form a concave surface and a convex surface at the bending portion 26. In addition, there are gaps between the pole pieces. These will affect the CB value of the battery cell and thus affect the thermodynamic parameters of some areas.

[0146] Therefore, the method 400 further includes: establishing a second control equation for the bend region 261 based on the effect of the bend region 261 on the preset CB value of the electrode assembly 2, wherein the parameters of the bend region 261 include the second control equation. Therefore, the second control equation for the bend region 261 can simulate the effect of the bend region 261 on the CB value of the electrode assembly 2. In particular, when the RVE model uses the electrode module 201 shown in Figure 3 to geometrically model the bend portion 26, the second control equation can be used to simulate the concave and convex surfaces generated by the bending of each electrode piece in the bend portion 26, as well as the gap between the cathode and anode electrodes, to distinguish them from the planar portion 25, thereby increasing the accuracy of the RVE model.

[0147] It should be understood that the process of establishing the second control equation in method 400 is similar to the process of establishing the second control equation in method 100, and for the sake of brevity, it will not be repeated.

[0148] In some embodiments, in the method 400, based on the influence of the bending region 261 on the preset CB value of the electrode assembly 2, establishing a second control equation for the bending region 261 can specifically include: determining the relationship between the CB value of the bending region 261 and the preset CB value based on the total thickness of the electrode module 201 in the bending region 261, the distance between the cathode active material layer 222 and the anode active material layer 212 in the bending region 261, and the number of winding layers of the electrode assembly 2, so as to establish a second control equation, the second control equation including the relationship between the CB value of the bending region 261 and the preset CB value. In this way, by combining the characteristics of the bending region 261 and reasonably adjusting the CB value of the bending region 261, the RVE model can be made more accurate and the numerical simulation effect more accurate. For example, the second control equation can include the above formula (8), but the embodiments of the present application are not limited to this.

[0149] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0150] The above text describes in detail the method for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application in combination with Figures 1 to 6. The following text describes the device for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application in combination with Figures 7 to 8.

[0151] As shown in FIG. 7 , the device 500 for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application includes: a processing unit 510 and an analyzing unit 520 .

[0152] Specifically, the processing unit 510 is used to: obtain the RVE model of the electrode assembly, which includes the electrode module of the electrode assembly; the analysis unit 520 is used to: perform numerical simulation on the electrode assembly according to the RVE model to analyze the lithium deposition situation of the electrode assembly.

[0153] Optionally, as an embodiment, the electrode module includes a planar area, which is used to form the end face with the largest area of ​​the electrode assembly; the processing unit 510 is used to: determine the parameters of the planar area to establish the RVE model, and the RVE model includes the planar area.

[0154] Optionally, as an embodiment, the processing unit 510 is configured to establish a control equation for the planar region based on the influence of stress on the wetting effect of the planar region, and the parameters of the planar region include the control equation for the planar region.

[0155] Optionally, as an embodiment, the processing unit 510 is used to: determine the porosity of different areas of the planar area based on the stress distribution of different areas of the planar area; based on Darcy's law, determine the seepage velocity of the electrolyte in the planar area based on the porosity of different areas of the planar area, and the control equation of the planar area includes the seepage velocity of the electrolyte in the planar area.

[0156] Optionally, as an embodiment, the electrode assembly is a wound electrode assembly, the electrode module includes a bending area, and the bending area is used to form a curved surface of the electrode assembly; the processing unit 510 is used to: determine the parameters of the bending area to establish the RVE model, and the RVE model includes the bending area.

[0157] Optionally, as an embodiment, the processing unit 510 is configured to establish a first control equation for the bending region based on the influence of stress on the wetting effect of the bending region, and the parameters of the bending region include the first control equation.

[0158] Optionally, as an embodiment, the processing unit 510 is used to: determine the porosity of different areas of the bending area according to the stress distribution of different areas of the bending area; based on Darcy's law, determine the seepage velocity of the electrolyte in the bending area according to the porosity of different areas of the bending area, and the first control equation includes the seepage velocity of the electrolyte in the bending area.

[0159] Optionally, as an embodiment, the processing unit 510 is used to establish a second control equation for the bending area according to the influence of the bending area on the preset CB value of the electrode assembly, and the parameters of the bending area include the second control equation.

[0160] Optionally, as an embodiment, the processing unit 510 is used to: determine the relationship between the CB value of the bending area and the preset CB value based on the total thickness of the electrode module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, so as to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

[0161] It should be understood that the device 500 according to the embodiment of the present application may correspond to executing the method 100 in the embodiment of the present application, and the above-mentioned and other operations and / or functions of each unit in the device 500 are respectively for implementing the corresponding processes of the method 100 in Figures 1 to 4. For the sake of brevity, they will not be repeated here.

[0162] Optionally, the device 500 of the embodiment of the present application can also be used to perform the method 300 of the embodiment of the present application. Specifically, the processing unit 510 is used to establish a third control equation based on the influence of stress on the wetting effect of the electrode sheet of the electrode assembly; the processing unit 510 is further used to establish a simulation model of the electrode assembly based on the parameters of the electrode assembly, where the parameters of the electrode assembly include the third control equation; and the analysis unit 520 is used to perform a numerical simulation of the electrode assembly based on the simulation model to analyze the lithium deposition of the electrode assembly.

[0163] Optionally, as an embodiment, the processing unit 510 is used to: determine the porosity of different areas of the electrode sheet of the electrode assembly based on the stress distribution of different areas of the electrode sheet of the electrode assembly; determine the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly based on the porosity of different areas of the electrode sheet of the electrode assembly based on Darcy's law, and the third control equation includes the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly.

[0164] Optionally, as an embodiment, the processing unit 510 is used to: establish an RVE model of the electrode assembly based on the parameters of the electrode assembly, the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes in sequence: a cathode current collector, a cathode active material layer, an isolation membrane, an anode active material layer and an anode current collector.

[0165] Optionally, as an embodiment, the pole piece module includes a planar area, and the processing unit 510 is used to establish a control equation for the planar area based on the influence of stress on the wetting effect of the planar area, and the third control equation includes the control equation for the planar area.

[0166] Optionally, as an embodiment, the electrode assembly is a wound electrode assembly, the electrode module includes a bending area, and the processing unit 510 is used to establish a first control equation for the bending area based on the influence of stress on the wetting effect of the bending area, and the third control equation includes the first control equation.

[0167] Optionally, as an embodiment, the processing unit 510 is further used to establish a second control equation for the bending area based on the influence of the bending area on the preset CB value of the electrode assembly, and the parameters of the electrode assembly include the second control equation.

[0168] Optionally, as an embodiment, the processing unit 510 is used to: determine the relationship between the CB value of the bending area and the preset CB value based on the total thickness of the electrode module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, so as to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

[0169] It should be understood that the device 500 according to the embodiment of the present application can correspond to executing the method 300 in the embodiment of the present application, and the above-mentioned and other operations and / or functions of each unit in the device 500 are respectively for implementing the corresponding process of the method 300 in Figure 5. For the sake of brevity, they will not be repeated here.

[0170] Optionally, the device 500 of the embodiment of the present application can also be used to perform the method 400 of the embodiment of the present application. Specifically, the processing unit 510 is used to: establish a simulation model of the electrode assembly based on the parameters of the bend portion of the wound electrode assembly, the simulation model including the bend portion; and the analysis unit 510 is used to: perform a numerical simulation of the electrode assembly based on the simulation model to analyze the lithium deposition of the electrode assembly.

[0171] Optionally, as an embodiment, the processing unit 510 is further configured to establish a first control equation of the bending portion according to the influence of stress on the wetting effect of the bending portion, and the parameters of the bending portion include the first control equation.

[0172] Optionally, as an embodiment, the processing unit 510 is used to: determine the porosity of different areas of the bend portion according to the stress distribution of different areas of the bend portion; based on Darcy's law, determine the seepage velocity of the electrolyte in the bend portion according to the porosity of different areas of the bend portion, and the first control equation includes the seepage velocity of the electrolyte in the bend portion.

[0173] Optionally, as an embodiment, the processing unit 510 is used to: establish an RVE model of the electrode assembly based on the parameters of the bending portion of the wound electrode assembly, the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes in sequence: a cathode current collector, a cathode active material layer, an isolation membrane, an anode active material layer and an anode current collector.

[0174] Optionally, as an embodiment, the processing unit 510 is used to: establish the RVE model according to the parameters of the bending area of ​​the pole piece module, the bending area is the area of ​​the pole piece module located at the bending portion, and the parameters of the bending portion include the parameters of the bending area.

[0175] Optionally, as an embodiment, the processing unit 510 is further used to: establish a second control equation for the bending area according to the influence of the bending area on the preset CB value of the electrode assembly, and the parameters of the bending area include the second control equation.

[0176] Optionally, as an embodiment, the processing unit 510 is used to: determine the relationship between the CB value of the bending area and the preset CB value based on the total thickness of the electrode module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, so as to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

[0177] It should be understood that the device 500 according to the embodiment of the present application may correspond to executing the method 400 in the embodiment of the present application, and the above-mentioned and other operations and / or functions of each unit in the device 500 are respectively for implementing the corresponding process of the method 400 in Figure 5. For the sake of brevity, they will not be repeated here.

[0178] Figure 8 is a schematic diagram of a device 600 for analyzing lithium deposition in an electrode assembly according to an embodiment of the present application. The device 600 shown in Figure 8 includes a processor 610, which can call and execute a computer program from a memory to implement method 100, method 300, or method 400 according to an embodiment of the present application.

[0179] Optionally, as shown in Figure 8, the device 600 may further include a memory 620. The processor 610 may call and execute a computer program from the memory 620 to implement the method 100, method 300, or method 400 in the embodiments of the present application.

[0180] The memory 620 may be a separate device independent of the processor 610 , or may be integrated into the processor 610 .

[0181] It should be understood that the processor 610 in the embodiment of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware.

[0182] It is understood that the memory 620 in the embodiment of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0183] It should be understood that the above-mentioned memories are exemplary but not restrictive. For example, the memories in the embodiments of the present application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM RAM (DR RAM), etc. In other words, the memories in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of memories.

[0184] An embodiment of the present application also provides a computer-readable storage medium for storing a computer program.

[0185] Optionally, the computer-readable storage medium can be applied to the device for analyzing lithium deposition in electrode assemblies in the embodiments of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the device for analyzing lithium deposition in electrode assemblies in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0186] An embodiment of the present application also provides a computer program product, including computer program instructions.

[0187] Optionally, the computer program product can be applied to the device for analyzing lithium deposition in electrode assemblies in the embodiments of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the device for analyzing lithium deposition in electrode assemblies in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0188] The embodiment of the present application also provides a computer program.

[0189] Optionally, the computer program can be applied to the device for analyzing lithium deposition in electrode assemblies in the embodiments of the present application. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the device for analyzing lithium deposition in electrode assemblies in the various methods of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0190] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A method for analyzing lithium deposition in an electrode assembly, characterized in that: include: Acquire a representative volume element (RVE) model of an electrode assembly, wherein the RVE model includes a pole piece module of the electrode assembly; According to the RVE model, numerical simulation is performed on the electrode assembly to analyze the lithium deposition of the electrode assembly.

2. The method according to claim 1, characterized in that The electrode module includes a planar area, and the planar area is used to form the end surface of the electrode assembly with the largest area; The step of obtaining a representative volume element RVE model of the electrode assembly includes: Parameters of the planar region are determined to establish the RVE model, wherein the RVE model includes the planar region.

3. The method according to claim 2, characterized in that The determining of the parameters of the plane area comprises: According to the influence of stress on the wetting effect of the planar area, a control equation of the planar area is established, and the parameters of the planar area include the control equation of the planar area.

4. The method according to claim 3, characterized in that The control equation of the plane area is established according to the influence of stress on the wetting effect of the plane area, including: determining the porosity of different regions of the planar region according to the stress distribution of different regions of the planar region; Based on Darcy's law, the seepage velocity of the electrolyte in the planar region is determined according to the porosity of different regions of the planar region, and the control equation of the planar region includes the seepage velocity of the electrolyte in the planar region.

5. The method according to any one of claims 1 to 4, characterized in that The electrode assembly is a wound electrode assembly, and the electrode module includes a bending area, and the bending area is used to form a curved surface of the electrode assembly; The step of obtaining a representative volume element RVE model of the electrode assembly includes: Parameters of the bending region are determined to establish the RVE model, wherein the RVE model includes the bending region.

6. The method according to claim 5, characterized in that The step of determining the parameters of the bending area includes: According to the influence of stress on the wetting effect of the bending area, a first control equation of the bending area is established, and the parameters of the bending area include the first control equation.

7. The method according to claim 6, characterized in that The first control equation of the bending area is established according to the influence of stress on the wetting effect of the bending area, including: Determining the porosity of different regions of the bending region according to stress distribution in different regions of the bending region; Based on Darcy's law, the seepage velocity of the electrolyte in the bending area is determined according to the porosity of different areas of the bending area, and the first control equation includes the seepage velocity of the electrolyte in the bending area.

8. The method according to any one of claims 5 to 7, characterized in that The step of determining the parameters of the bending area includes: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, and the parameters of the bending area include the second control equation.

9. The method according to claim 8, characterized in that According to the influence of the bending area on the capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, including: According to the total thickness of the pole piece module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, the relationship between the CB value of the bending area and the preset CB value is determined to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

10. A method for analyzing lithium deposition in an electrode assembly, characterized in that: include: According to the influence of stress on the wetting effect of the electrode sheet of the electrode assembly, a third control equation is established; Establishing a simulation model of the electrode assembly according to parameters of the electrode assembly, wherein the parameters of the electrode assembly include the third control equation; According to the simulation model, numerical simulation is performed on the electrode assembly to analyze the lithium deposition situation of the electrode assembly.

11. The method according to claim 10, characterized in that According to the influence of stress on the wetting effect of the electrode sheet of the electrode assembly, the third control equation is established, which includes: Determining the porosity of different regions of the electrode sheet of the electrode assembly according to the stress distribution of different regions of the electrode sheet of the electrode assembly; Based on Darcy's law, the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly is determined according to the porosity of different regions of the electrode sheet of the electrode assembly, and the third control equation includes the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly.

12. The method according to claim 10 or 11, characterized in that: The step of establishing a simulation model of the electrode assembly according to the parameters of the electrode assembly includes: According to the parameters of the electrode assembly, a representative volume element RVE model of the electrode assembly is established, and the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes: a cathode current collector, a cathode active material layer, a separator, an anode active material layer and an anode current collector in sequence.

13. The method according to claim 12, characterized in that The pole piece module comprises a planar area, According to the influence of stress on the wetting effect of the electrode sheet of the electrode assembly, a third control equation is established, including: According to the influence of stress on the wetting effect of the planar area, a control equation of the planar area is established, and the third control equation includes the control equation of the planar area.

14. The method according to claim 12 or 13, characterized in that The electrode assembly is a wound electrode assembly, and the electrode module includes a bending area. According to the influence of stress on the wetting effect of the electrode sheet of the electrode assembly, a third control equation is established, including: According to the influence of stress on the wetting effect of the bending area, a first control equation of the bending area is established. The third control equation includes the first control equation.

15. The method according to claim 14, characterized in that The method comprises: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, and the parameters of the electrode assembly include the second control equation.

16. The method according to claim 15, characterized in that The second control equation of the bending area is established according to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, including: According to the total thickness of the pole piece module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, the relationship between the CB value of the bending area and the preset CB value is determined to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

17. A method for analyzing lithium deposition in an electrode assembly, characterized in that: include: According to the parameters of the bent portion of the wound electrode assembly, a simulation model of the electrode assembly is established, wherein the simulation model includes the bent portion; According to the simulation model, numerical simulation is performed on the electrode assembly to analyze the lithium deposition situation of the electrode assembly.

18. The method according to claim 17, characterized in that The method comprises: According to the influence of stress on the wetting effect of the bending portion, a first control equation of the bending portion is established, and the parameters of the bending portion include the first control equation.

19. The method according to claim 18, characterized in that The first control equation of the bending portion is established according to the influence of stress on the wetting effect of the bending portion, including: Determining the porosity of different regions of the bending portion according to stress distribution in different regions of the bending portion; Based on Darcy's law, the seepage velocity of the electrolyte in the bend is determined according to the porosity of different regions of the bend, and the first control equation includes the seepage velocity of the electrolyte in the bend.

20. The method according to any one of claims 17 to 19, characterized in that The method of establishing a simulation model of the electrode assembly according to the parameters of the bending portion of the wound electrode assembly comprises: According to the parameters of the bending part of the wound electrode assembly, a representative volume element RVE model of the electrode assembly is established. The RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes: a cathode current collector, a cathode active material layer, an isolation membrane, an anode active material layer and an anode current collector in sequence.

21. The method according to claim 20, characterized in that The method of establishing a representative volume element RVE model of the electrode assembly according to the parameters of the bending portion of the wound electrode assembly comprises: The RVE model is established according to the parameters of the bending region of the pole piece module, the bending region is a region of the pole piece module located at the bending portion, and the parameters of the bending portion include the parameters of the bending region.

22. The method according to claim 21, characterized in that The method further comprises: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, and the parameters of the bending area include the second control equation.

23. The method according to claim 22, characterized in that The second control equation of the bending area is established according to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, including: According to the total thickness of the pole piece module in the bending area, the cathode active material in the bending area The distance between the layer and the anode active material layer, and the number of winding layers of the electrode assembly are used to determine the relationship between the CB value of the bending area and the preset CB value to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

24. A device for analyzing lithium deposition in an electrode assembly, characterized in that: include: A processing unit, used for obtaining a representative volume element RVE model of the electrode assembly, wherein the RVE model includes a pole piece module of the electrode assembly; The analysis unit is used to perform numerical simulation on the electrode assembly according to the RVE model to analyze the lithium deposition of the electrode assembly.

25. The device according to claim 24, characterized in that The electrode module includes a planar area, and the planar area is used to form the end surface of the electrode assembly with the largest area; The processing unit is used for: Parameters of the planar region are determined to establish the RVE model, wherein the RVE model includes the planar region.

26. The device according to claim 25, characterized in that The processing unit is used for: According to the influence of stress on the wetting effect of the planar area, a control equation of the planar area is established, and the parameters of the planar area include the control equation of the planar area.

27. The device according to claim 26, characterized in that The processing unit is used for: determining the porosity of different regions of the planar region according to the stress distribution of different regions of the planar region; Based on Darcy's law, the seepage velocity of the electrolyte in the planar region is determined according to the porosity of different regions of the planar region, and the control equation of the planar region includes the seepage velocity of the electrolyte in the planar region.

28. Apparatus according to any one of claims 24 to 27, characterised in that The electrode assembly is a wound electrode assembly, and the electrode module includes a bending area, and the bending area is used to form a curved surface of the electrode assembly; The processing unit is used for: Parameters of the bending region are determined to establish the RVE model, wherein the RVE model includes the bending region.

29. The device according to claim 28, characterized in that The processing unit is used for: According to the influence of stress on the wetting effect of the bending area, a first control equation of the bending area is established, and the parameters of the bending area include the first control equation.

30. The device according to claim 29, characterized in that The processing unit is used for: Determining the porosity of different regions of the bending region according to stress distribution in different regions of the bending region; Based on Darcy's law, the seepage velocity of the electrolyte in the bending area is determined according to the porosity of different areas of the bending area, and the first control equation includes the seepage velocity of the electrolyte in the bending area.

31. Apparatus according to any one of claims 28 to 30, characterised in that The processing unit is used for: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, the bending area is established The parameters of the bending region include the second control equation of the domain.

32. The device according to claim 31, characterized in that The processing unit is used for: According to the total thickness of the pole piece module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, the relationship between the CB value of the bending area and the preset CB value is determined to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

33. A device for analyzing lithium deposition in an electrode assembly, characterized in that: include: A processing unit, used for establishing a third control equation according to the influence of stress on the wetting effect of the electrode piece of the electrode assembly; The processing unit is further used to: establish a simulation model of the electrode assembly according to parameters of the electrode assembly, wherein the parameters of the electrode assembly include the third control equation; The analysis unit is used to perform numerical simulation on the electrode assembly according to the simulation model to analyze the lithium deposition situation of the electrode assembly.

34. The device according to claim 33, characterized in that The processing unit is used for: Determining the porosity of different regions of the electrode sheet of the electrode assembly according to the stress distribution of different regions of the electrode sheet of the electrode assembly; Based on Darcy's law, the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly is determined according to the porosity of different regions of the electrode sheet of the electrode assembly, and the third control equation includes the seepage velocity of the electrolyte in the electrode sheet of the electrode assembly.

35. Apparatus according to claim 33 or 34, characterised in that The processing unit is used for: According to the parameters of the electrode assembly, a representative volume element RVE model of the electrode assembly is established, and the RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes: a cathode current collector, a cathode active material layer, a separator, an anode active material layer and an anode current collector in sequence.

36. The device according to claim 35, characterized in that The pole piece module comprises a planar area, The processing unit is used for: According to the influence of stress on the wetting effect of the planar area, a control equation of the planar area is established, and the third control equation includes the control equation of the planar area.

37. Apparatus according to claim 35 or 36, characterised in that The electrode assembly is a wound electrode assembly, and the electrode module includes a bending area. The processing unit is used for: According to the influence of stress on the wetting effect of the bending area, a first control equation of the bending area is established, and the third control equation includes the first control equation.

38. The device according to claim 37, characterized in that The processing unit is also used for: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, and the parameters of the electrode assembly include the second control equation.

39. The device according to claim 38, characterized in that The processing unit is used for: The bending area is determined according to the total thickness of the electrode module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly. The relationship between the CB value of the bending area and the preset CB value is used to establish the second control equation, wherein the second control equation includes the relationship between the CB value of the bending area and the preset CB value.

40. A device for analyzing lithium deposition in an electrode assembly, characterized in that: include: A processing unit, configured to establish a simulation model of the electrode assembly according to parameters of the bent portion of the wound electrode assembly, wherein the simulation model includes the bent portion; The analysis unit is used to perform numerical simulation on the electrode assembly according to the simulation model to analyze the lithium deposition situation of the electrode assembly.

41. The device according to claim 40, characterized in that The processing unit is also used for: According to the influence of stress on the wetting effect of the bending portion, a first control equation of the bending portion is established, and the parameters of the bending portion include the first control equation.

42. The device according to claim 41, characterized in that The processing unit is used for: Determining the porosity of different regions of the bending portion according to stress distribution in different regions of the bending portion; Based on Darcy's law, the seepage velocity of the electrolyte in the bend is determined according to the porosity of different regions of the bend, and the first control equation includes the seepage velocity of the electrolyte in the bend.

43. Apparatus according to any one of claims 40 to 42, characterised in that The processing unit is used for: According to the parameters of the bending part of the wound electrode assembly, a representative volume element RVE model of the electrode assembly is established. The RVE model includes a pole piece module of the electrode assembly, and the pole piece module includes: a cathode current collector, a cathode active material layer, an isolation membrane, an anode active material layer and an anode current collector in sequence.

44. The device according to claim 43, characterized in that The processing unit is used for: The RVE model is established according to the parameters of the bending region of the pole piece module, the bending region is a region of the pole piece module located at the bending portion, and the parameters of the bending portion include the parameters of the bending region.

45. The device according to claim 44, characterized in that The processing unit is also used for: According to the influence of the bending area on the preset capacity balance CB value of the electrode assembly, a second control equation of the bending area is established, and the parameters of the bending area include the second control equation.

46. ​​The device according to claim 45, characterized in that The processing unit is used for: According to the total thickness of the pole piece module in the bending area, the distance between the cathode active material layer and the anode active material layer in the bending area, and the number of winding layers of the electrode assembly, the relationship between the CB value of the bending area and the preset CB value is determined to establish the second control equation, which includes the relationship between the CB value of the bending area and the preset CB value.

47. A device for analyzing lithium deposition in an electrode assembly, characterized in that: include: A processor and a memory, the memory being used to store a computer program, and the processor being used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 23.

48. A computer-readable storage medium, characterized in that Used to store a computer program, the computer program causing a computer to execute the method according to any one of claims 1 to 23.

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