Battery interface current calculation method, system and storage medium

Abstract

The present application discloses a method, device, and storage medium for calculating the interface current of an all-solid-state battery. The battery comprises the following multiple components stacked in sequence: a positive electrode current collector, a positive electrode, an insulating member, a solid electrolyte layer, a negative electrode, and a negative electrode current collector; the insulating member is arranged in a ring shape and covers a portion of the outer periphery of the positive electrode; the positive electrode comprises a first portion not covered by the insulating member and a second portion covered by the insulating member; the solid electrolyte layer comprises a third portion corresponding to the second portion and a fourth portion located outside the third portion; the method comprises: calculating the ion flux of each portion: calculating the stress distribution of the first and second portions of the positive electrode respectively, and calculating the positive electrode ion flux based on the stress distribution; calculating the stress distribution of the third and fourth portions of the solid electrolyte layer respectively, and calculating the solid electrolyte layer ion flux based on the stress distribution; and calculating the current at the negative electrode interface based on the ion flux.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, and storage medium for calculating the interface current of a battery. Background Art

[0002] With the rapid development of energy technology, solid-state batteries have become a new type of battery with great application prospects. The main difference between solid-state batteries and traditional lithium-ion batteries lies in the state of the electrolyte: solid-state batteries use solid electrolytes, while traditional lithium-ion batteries use liquid electrolytes. The use of solid electrolytes can affect ion transport, electron blocking, and interfacial contact within the battery. This affects the current distribution within the battery and at the interfaces between different components, which is the magnitude of the interfacial current. High interfacial current means high charge transfer efficiency and fast redox reactions, which improves the battery's output power. It also means faster charging and discharging rates. At high current densities, concentration polarization and electrochemical polarization at the interfaces between battery components are weakened, bringing the battery's output voltage closer to the theoretical value and improving energy conversion efficiency. Furthermore, in lithium metal anode systems, high interfacial current helps suppress lithium dendrite growth. Therefore, high interfacial current is key to improving the power density and energy efficiency of solid-state batteries, especially in fast charging and high-performance scenarios. This makes the interfacial current parameter a crucial reference in the design and manufacture of solid-state batteries.

[0003] In solid-state batteries, solid electrolytes replace traditional diaphragms to become barriers between the positive and negative electrodes. Since the solid electrolyte membrane itself has poor mechanical properties and cannot form a complete wrapping structure for the positive electrode, the burr problem on the edge of the positive electrode is relatively serious. In the prior art, there is a solution to set an insulating structure on the edge of the positive electrode to reduce the risk of short circuits caused by burrs. However, there is no report on the method of setting an insulating component at the contact interface between the solid electrolyte layer and the positive electrode layer. The applicant has confirmed in previous studies that the insulating frame part set between the positive electrode and the solid electrolyte layer helps to improve the performance of the battery. However, since the insulating structure part intervenes between the positive electrode and the solid electrolyte, it affects the ion path between the positive and negative electrodes. Whether this structure will cause electrochemical performance is still unknown. For this reason, it is very necessary to simulate the electrochemical performance of the battery structure with the help of simulation methods. Summary of the Invention

[0004] To achieve the above objectives, this application discloses an interface current calculation method, system, and storage medium. The interface current calculation method can accurately calculate the interface current of batteries, especially new solid-state batteries with insulating components, providing an important basis for battery design and production.

[0005] The first aspect of the present application provides a method for calculating the interface current of an all-solid-state battery. The battery includes the following multiple components stacked in sequence: a positive electrode current collector, a positive electrode, an insulating member, a solid electrolyte layer, a negative electrode, and a negative electrode current collector; the insulating member is arranged in a ring shape and covers a portion of the outer periphery of the positive electrode; the insulating member is arranged in a ring shape and covers a portion of the outer periphery of the positive electrode; the positive electrode includes a first portion not covered by the insulating member and a second portion covered by the insulating member; the solid electrolyte layer includes a third portion corresponding to the second portion and a fourth portion located outside the third portion; the interface current calculation method may include: step S1. calculating the ion flux of each portion; step S1-1. calculating the stress distribution of the first and second portions of the positive electrode respectively, and calculating the positive electrode ion flux based on the stress distribution; step S1-2. calculating the stress distribution of the third and fourth portions of the solid electrolyte layer respectively, and calculating the solid electrolyte layer ion flux based on the stress distribution; step S2. calculating the interface current of two locations where the negative electrode faces the center region of the positive electrode and the edge region of the positive electrode based on the ion flux calculated in step S1.

[0006] According to some embodiments of the present application, the second portion of the positive electrode accounts for 1%-10% of the positive electrode.

[0007] According to some embodiments of the present application, step S1 further includes step S1-3. calculating the negative electrode ion flux, where the negative electrode is metallic lithium.

[0008] According to some embodiments of the present application, the stress distribution of the first portion of the positive electrode satisfies: ;in, is the area of ​​the second part, is the area of ​​the insulating member, is the positive electrode Young's modulus, is the Young's modulus of the insulating component, is the external load.

[0009] According to some embodiments of the present application, step S2 further includes determining a current density distribution using the ion flux; and determining the interface current based on the current density distribution.

[0010] According to some embodiments of the present application, the Young's modulus of the insulating member is different from the Young's modulus of the positive electrode.

[0011] A second aspect of the present application provides a device for calculating an interface current of a battery. The battery comprises the following multiple components stacked in sequence: a positive electrode current collector, a positive electrode, a solid electrolyte layer, a negative electrode, and a negative electrode current collector; an insulating member having the same cross-sectional area as the positive electrode covers the portion of the positive electrode adjacent to the solid electrolyte in a contact and pressure-applying manner. The device for calculating the interface current may include a first determination module, a second determination module, and a third determination module, each performing operations on the positive electrode, the solid electrolyte, and the negative electrode. The first determination module is configured to determine the hydrostatic stress distribution and ion concentration of each component; the second determination module is configured to determine the ion flux using the hydrostatic stress distribution and the ion concentration; the third determination module is configured to determine the interface current based on the ion flux; wherein the ion concentration is determined based on Fick's diffusion law, the hydrostatic stress distribution is determined based on the ion concentration and the Poisson's ratio, Young's modulus and partial molar volume of one or more components related to the positive electrode, the solid electrolyte or the negative electrode; the ion flux is determined based on the ion diffusion coefficient, the hydrostatic stress distribution, the ion concentration and the partial molar volume; and the interface current is also related to the Faraday constant.

[0012] The third aspect of the present application provides a computing system, which may include: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the interface current calculation method described above may be implemented.

[0013] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the interface current calculation method described above can be implemented.

[0014] In a fifth aspect, the present application provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of the interface current calculation method described above can be implemented.

[0015] In a sixth aspect, the present application provides a device for calculating the interface current of a battery, and the interface current calculation may include the interface current calculation method device or calculation system as described above.

[0016] The interface current calculation method disclosed in this application can accurately calculate the interface current of batteries, especially new solid-state batteries with insulating components, providing an important basis for battery design and production.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present application will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0019] Figure 1 is an exemplary structural schematic diagram and cross-sectional diagram of a solid-state battery according to the present application;

[0020] Figure 2 is an exemplary flow chart of a method for determining an interface current according to some embodiments of the present application;

[0021] Figure 3 is an exemplary diagram of a current density distribution diagram and a local enlarged diagram according to some embodiments of the present application;

[0022] Figure 4 is an exemplary diagram of another current density distribution diagram and a local enlarged diagram according to some embodiments of the present application;

[0023] Figure 5 is an exemplary diagram of another current density distribution diagram and a local enlarged diagram according to some embodiments of the present application;

[0024] Figure 6 is an exemplary module diagram of a device for calculating the interface current of a battery according to some embodiments of the present application; and

[0025] Figure 7 is an exemplary block diagram of a computing device according to some embodiments of the present application. DETAILED DESCRIPTION

[0026] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0027] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Words such as "include" or "comprise" used in this application mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The terms "and / or" or "and / or" used in this application include any and all combinations of one or more related listed items.

[0028] The terms "including", "having" and their cognates used in this application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items.

[0029] It should be noted that the terms "first", "second", "third", etc. used in this application are only used to distinguish descriptions and should not be understood as indicating or implying relative importance. When a component is referred to as being "fixed to", "mounted on" or "set on" another component, it can be directly on the other component or there can be other components in the middle. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be other components in the middle at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0030] Some preferred embodiments of the present application are described below. It should be noted that the following description is for illustrative purposes and is not intended to limit the scope of protection of the present application. The steps involved in the present application can be performed precisely in order, or various steps can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more operations can be removed from these processes.

[0031] The present application provides a method for determining the interface current of an all-solid-state battery, wherein the all-solid-state battery may include: Figure 1 The solid-state battery 100 shown may include a plurality of components stacked in sequence: a positive electrode current collector 110 , a positive electrode 120 , an insulating member 130 , a solid electrolyte layer 140 , a negative electrode 150 , and a negative electrode current collector 160 .

[0032] The positive electrode current collector 110 and the negative electrode current collector 160 can be formed of a conductive material, such as a foil, plate, or mesh made of stainless steel, nickel (Ni), aluminum (Al), iron (Fe), titanium (Ti), copper (Cu), palladium (Pd), gold (Au), or platinum (Pt), or alloys of two or more of the above materials. For example, the positive electrode current collector 110 and the negative electrode current collector 160 can be a cladding material formed by decomposing copper foil or laminating different metal foils.

[0033] The positive electrode may contain a material capable of intercalating or deintercalating metal ions such as lithium ions, such as a positive electrode active material, and examples thereof may include lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, or transition metal oxynitrides. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O2 or LiCoO2.

[0034] The negative electrode may also be a material containing metal ions capable of intercalating or deintercalating lithium ions, such as a negative electrode active material, exemplified by metal materials, carbon materials, oxides, nitrides, tin compounds, silicon compounds, and the like. The metal material may be a single metal or an alloy, such as lithium metal or a lithium alloy. The carbon material may be natural graphite, coke, graphitizable carbon, carbon fiber, spherical carbon, artificial graphite, or amorphous carbon. Alternatively or preferably, the negative electrode may be a lithium metal negative electrode.

[0035] At least one of the positive electrode or the negative electrode may further contain a conductive additive, for example, a carbon-based material such as graphite (natural graphite or artificial graphite), carbon black (acetylene black or Ketjen black), carbon nanotubes, graphene, etc.; a metal-based material such as metal powder (aluminum powder, nickel powder, etc.), metal oxides (titanium oxide, etc.), metal whiskers (aluminum oxide, oxidizing agents, etc.); a conductive polymer such as polyaniline, polypyrrole, polythiophene, etc.; a conductive fiber such as carbon fiber, metal fiber, metal compound fiber, polymer fiber, etc. The conductive additive may also be a mixture of one or more of the above.

[0036] The solid electrolyte layer 140 may be in the form of a layer or a film, and may include an oxide solid electrolyte, a halide solid electrolyte, or a sulfide solid electrolyte. For example, the oxide solid electrolyte may include a NASICON solid electrolyte such as LiTi2(PO4)3 or its element substitution body, a perovskite solid electrolyte such as (LaLi)TiO3, a Li 14 ZnGe4O 16 , LISICON type solid electrolytes such as Li4SiO4, LiGeO4 or their element substitution bodies, Li7La3Zr2O 12Or a garnet-type solid electrolyte such as a garnet-type solid electrolyte or an element substitution body thereof, or Li3PO4 or an N substitution body thereof. For example, the oxide solid electrolyte may include one or more of LLZO, LLTO, LAGP, LATP, LBSPO, LPO, Li3PO4, Li4SiO4, Li2ZnTi3O8, and / or one or more of their derivatives. The halide solid electrolyte may include a lithium halide solid electrolyte, which may be a solid electrolyte having the chemical formula Li a MX b Indicates, M represents a metal element or a metalloid element, and X represents a halogen element. Wherein, "metalloid element" can represent an element with metal-like properties, and can include B, Si, Ge, As, Sb, Te, etc. Optionally or preferably, M can include but is not limited to Al, Zn, Mg, Ca, Ba, Mn, Cd, Co, Yb, Y, Cr, In, Ga, Sr, Hf, Ti, Ta, Sn, Nb, Er, Sc, etc. or any combination thereof. For example, the halide solid electrolyte can include Li2ZrCl6 or its derivatives. The sulfide solid electrolyte can include lithium sulfides such as Li2S-P2S5 system, Li2S-SiS2 system, Li2S-B2S3 system, Li2S-GeS2 system, Li2S-SiS2-LiI system, Li2S-SiS2-Li3PO4 system, Li2S-Ge2S2 system, Li2S-GeS2.P2S5 system or Li2S-GeS2-ZnS system. For example, sulfide solid electrolytes may include LGPS, The solid electrolyte layer 140 may include one or more of the above materials. In some implementations, the solid electrolyte layer 140 may include a solid electrolyte having lithium ion conductivity.

[0037] The solid-state battery 100 may further include an insulating member 130. The insulating member 130 may cover the outer side of the portion of the positive electrode 120 close to the solid electrolyte layer 140 and contact and pressurize the portion. For example, the insulating member 130 may be provided in a ring shape and cover a portion of the outer periphery of the positive electrode 120. Figure 1 As shown, it can be considered that the outer side of the lower portion of the positive electrode 120 is covered by the insulating member 130. The insulating member 130 can achieve the barrier to foreign matter (such as air, moisture, fine dust, etc.), and improve the cycle performance and safety of the solid-state battery 100. In one implementation, the insulating member 130 can have the same cross-sectional area as the positive electrode 120, so as to maintain the uniformity of the solid-state battery design. For example, assuming the size (length) of the positive electrode 120 is Width Thickness) is , then the outer dimensions of the insulating member (length Width thickness) can be Thus, after adding the insulating member 130, the cross-sectional area of ​​the portion of the positive electrode 120 in contact with the solid electrolyte layer 140 (i.e., the portion subjected to pressure) is reduced. The length and width dimensions of the insulating member 130 can be adjusted based on actual conditions, so as not to affect the energy density of the solid-state battery 100.

[0038] The method for determining the interface current of the battery provided in this application can refer to Figure 2 , wherein the process 200 shown can be implemented in a computing device, such as an industrial computer, a server, a computer, a tablet, a smart mobile device, etc. In some embodiments, the process 200 can be stored in a storage device (such as the above-mentioned computing device's own storage unit or an external storage device) in the form of a program or instruction, and the program or instruction can implement the process 200 when executed. In some embodiments, the process 200 can be executed separately for the relevant components (including the positive electrode, the solid electrolyte, and the negative electrode) of the battery (for example, the solid-state battery 100). In the present application, a coordinate system can be first established based on the battery (that is, the solid-state battery 100) to facilitate subsequent various mathematical calculations. Return to reference Figure 1 ,by Figure 1 The direction of the arrow shown in the x Axis, that is, along the thickness direction of the solid-state battery 100. Then perpendicular to x Axis establishment yoz plane, that is, along the length and width directions of the solid-state battery 100, respectively y Axis and z In this way, the position of a certain mass point belonging to the solid-state battery 100 can be expressed as a point in the above coordinate system ( x , y , z ) indicates that. At the same time, you can use x The coordinates are used to indicate which component or interface of the solid-state battery 100 the particle is located at. x 1 is the outer surface position of the positive electrode 120, that is, at the interface between the positive electrode current collector 110 and the positive electrode 120. x 2 is the interface position between the positive electrode 120 and the insulating member 130, x 3 is the interface position between the positive electrode 120 and the solid electrolyte layer 140, x 4 is the interface position between the solid electrolyte layer 140 and the negative electrode 150, x 5 is the outer surface position of the negative electrode 150, that is, the interface between the negative electrode 150 and the negative electrode current collector 160. The above can be recorded as x k Thus, the region where charge transfer occurs in the solid-state battery 100 can be represented by the x-coordinate, including the positive electrode 120: x 1<x < x 3. Solid electrolyte layer 140: x 3< x < x 4. And the negative electrode: x 4< x < x 5. By calculating the current density distribution in each area, the current distribution of the entire battery can be obtained, and then the magnitude of the interface current can be obtained.

[0039] In addition, since the insulating member 130 covers a portion of the outer periphery of the positive electrode 120, the positive electrode 120 can also be divided into multiple parts. For example, the positive electrode 120 can be divided into a first part P1 not covered by the insulating member 130 and a second part P2 covered by the insulating member 130. Due to the contact pressure of the insulating member 130, the physical parameters related to the first part P1 and the second part P2 will change, thereby affecting the corresponding calculation process. Combined with the aforementioned position division, the first part P1 can be expressed as: x 1< x < x 2. The second part P2 can be expressed as: x 2< x < x 3. In one implementation, the second portion P2 accounts for 1%-10% of the positive electrode.

[0040] At the same time, the solid electrolyte layer 140 is in contact with the positive electrode 120 and the insulating member 130, and will also be affected. Similarly or similarly, the solid electrolyte layer 140 can also be divided. For example, the solid electrolyte layer 140 can be divided into a third part P3 corresponding to the second part P2 (e.g., Figure 1 The portion between the two dashed lines in Figure 1) and the fourth portion P4 outside the third portion P3. The second portion P2 of the positive electrode 120, which is in contact with pressure, will affect the relevant physical parameters of a portion of the solid electrolyte layer 140, namely the third portion P3. Similarly, the calculation process for different regions will be different.

[0041] Return Reference Figure 2 , process 200 may include the following operations.

[0042] S1: Calculate the ion flux of each part.

[0043] The above step S1 may include the following operations.

[0044] S1-1: Calculate the stress distribution of the first part and the second part of the positive electrode respectively, and calculate the positive electrode ion flux based on the stress distribution.

[0045] For positive electrode 120 ( x1< x < x 3), the corresponding ion concentration satisfies Fick's diffusion law. For example, the ion concentration satisfies the following formula (1):

[0046]

[0047] Among them, the subscript Indicates the positive electrode, represents the ion concentration, represents the ion diffusion coefficient, Indicates location, Indicates time, Represents the boundary conditions. The boundary conditions for the above equation (1) can be expressed as the following equation (2), and the initial conditions can be expressed as the following equation (3):

[0048]

[0049] in, represents the cathode reaction rate, Represents the external input current, which is a known value. Indicates the number of electrons participating in the reaction at the positive electrode, represents the Faraday constant, Represents the initial known concentration. Based on the above conditions, the ion concentration related to the positive electrode 120 can be obtained by solving equation (1): expression.

[0050] The hydrostatic stress distribution corresponding to the positive electrode 120 can be determined based on the above-mentioned ion concentration and the Poisson's ratio, Young's modulus, and partial molar volume of the positive electrode 120. For example, the hydrostatic stress distribution can be expressed as the following formula (4):

[0051]

[0052] in, represents the hydrostatic stress distribution, represents Poisson's ratio, represents Young's modulus, represents the partial molar volume, Indicates the initial stress of the positive electrode. Combined with the above description, the positive electrode 120 will cause the internal initial stress of the positive electrode 120 to change due to the pressure contact of the insulating member 130. That is, for the first part P1: x 1< x < x 2 and the second part P2: x 2< x < x3 The initial stresses of the two regions are different. For example, the first part P1 and the second part P2 have different initial stress distributions, and their corresponding first initial stress distributions are And the second initial stress distribution In view of the determination of the above initial stress distribution, the initial stress of different regions can be obtained based on the stress equilibrium equation and the principle of equal force at the continuous interface, and then brought into the above formula (4) to calculate the hydrostatic stress distribution, thus obtaining different first hydrostatic stress distributions. And the second hydrostatic stress distribution .

[0053] For example, the second portion P2 of the positive electrode 120 ( x 2< x < x 3) Stress distribution (that is, initial stress distribution ) can be determined based on the following formula (5):

[0054]

[0055] in, represents the area of ​​the second portion P2, which may be the outer area of ​​the second portion P2 being covered. represents the area of ​​the insulating member 130, which may be the outer area of ​​the insulating member 130. represents the positive electrode Young's modulus, represents the Young's modulus of the insulating member 130, In some implementations, the positive electrode and the insulating member have different Young's moduli.

[0056] The ion flux corresponding to the positive electrode 120 can be determined based on the ion concentration, the hydrostatic stress distribution, the ion diffusion coefficient, and the partial molar volume. For example, the ion flux can be expressed as follows (6):

[0057]

[0058] in, represents the ion flux, represents the ion concentration, Indicates the maximum storage ion concentration of the positive electrode, which is used to indicate the degree of lithiation. represents the ideal gas constant, which is 8.314 J / (mol·K). represents the temperature. The initial conditions and boundary conditions for the above equation (6) can be expressed as follows:

[0059]

[0060] Among them, when located x = x 1, that is, at the interface between the positive electrode 120 and the positive electrode current collector 110, the ion flux is 0. x = x At 3, which is the interface between the positive electrode 120 and the solid electrolyte layer 140, the ion flux can be the quotient between the current density and the Faraday constant. Based on the above conditions and the aforementioned ion concentration and hydrostatic stress distribution, equation (6) is solved to obtain the current density distribution related to the positive electrode 120. For example, the current density distribution related to the positive electrode 120 is It can be expressed as the following formula (9):

[0061]

[0062] in, can be expressed as the solved ion flux, represents the Faraday constant. Based on the above formula (9), the value x = x 2 or x = x 3, the interface current at the interface between the positive electrode 120 and the insulating member 130, or the interface current at the interface between the positive electrode 120 and the solid electrolyte layer 140 can be obtained. and By using different combinations of , we can get the current magnitude at different positions on the above interface.

[0063] The aforementioned hydrostatic stress distribution includes different first hydrostatic stress distributions And the second hydrostatic stress distribution , then combined with formula (6), the ion flux associated with the positive electrode 120 may include different first ion fluxes and the second ion flux , so that the current density distribution of the positive electrode 120 is based on x There are two different expressions due to the difference in . That is, formula (9) can also be expressed as:

[0064]

[0065] S1-2: Calculate the stress distribution of the third and fourth parts of the solid electrolyte layer respectively, and calculate the ion flux of the solid electrolyte layer based on the stress distribution.

[0066] For the solid electrolyte layer 140 ( x 3< x < x4), its ion concentration and hydrostatic stress distribution can be the same or similar to the relevant calculations of the positive electrode 120. For example, the ion concentration satisfies the following formula (10):

[0067]

[0068] Among them, the subscript represents a solid electrolyte, represents the ion concentration, represents the ion diffusion coefficient, which can be calculated based on the following formula (11):

[0069]

[0070] represents the diffusion coefficient of lithium ions, represents the diffusion coefficient of negative ions. For the solution of Equation (10), the boundary conditions can be x = x 3 interface, the ion flux of the positive electrode 120 and the solid electrolyte layer 140 is the same, and the initial condition can be that the ion concentration at the initial moment is the initial known concentration Solving the above equation (10) based on the above conditions can yield the ion concentration associated with the solid electrolyte layer 140: expression.

[0071] The hydrostatic stress distribution corresponding to the solid electrolyte layer 140 can be determined based on the above-mentioned ion concentration and the Poisson's ratio, Young's modulus, and partial molar volume of the solid electrolyte layer 140. For example, the hydrostatic stress distribution can be expressed as the following formula (12):

[0072]

[0073] in, represents the hydrostatic stress distribution, represents Poisson's ratio, represents Young's modulus, represents the partial molar volume, Represents the initial stress of the solid electrolyte. With respect to the initial stress, the solid electrolyte layer 140 in contact with the positive electrode 120 is affected due to the contact pressure exerted by the insulating member 130 on the positive electrode 120. For example, the relevant physical parameters of the solid electrolyte layer 140 corresponding to the portion of the positive electrode 120 covered by the insulating member 130 and the portion corresponding to the insulating member 130 and the portion outside the insulating member 130 will change. In the present application, the solid electrolyte layer 140 can be divided into a third portion P3 corresponding to the second portion P2 and a fourth portion P4 located outside the third portion P3. The initial stress distributions of the two portions are different, including the corresponding initial stress distributions and the initial hydrostatic stress distribution The calculation of the initial stress distribution of the third portion P3 and the fourth portion P4 may be the same or similar to the calculation process of the first portion P1 and the second portion P2 related to the aforementioned positive electrode, and reference may be made to the corresponding description.

[0074] For partial molar volume , which can be calculated based on the following formula (13):

[0075]

[0076] represents the partial molar volume of lithium ions, represents the partial molar volume of the negative ion. Substituting the relevant parameters and equations into equation (12) can calculate the hydrostatic stress distribution and obtain the third hydrostatic stress distribution And the fourth hydrostatic stress distribution .

[0077] The ion flux corresponding to the solid electrolyte layer 140 can be determined based on the ion concentration, the hydrostatic stress distribution, the ion diffusion coefficient, and the partial molar volume. For example, the ion flux can be expressed as follows (14):

[0078]

[0079] in, represents the ion flux, represents the partial molar volume of the electrolyte, represents the ion concentration, represents the ideal gas constant, which is 8.314 J / (mol·K). Indicates temperature. At the same time, the calculation formula of the current exchange density related to the solid electrolyte layer 140 is as follows (15):

[0080]

[0081] in, represents the electric potential. The initial conditions and boundary conditions for the above equations can be expressed as follows:

[0082]

[0083] Based on the above conditions and the aforementioned ion concentration and hydrostatic stress distribution, the current density distribution related to the solid electrolyte layer 140 can be obtained. For example, the current density distribution related to the solid electrolyte layer 140 is It can be expressed as the following formula (20):

[0084]

[0085] Based on the above formula (9), the value x = x 3 or x = x 4, the interface current at the interface between the solid electrolyte layer 140 and the positive electrode 120, or the interface current at the interface between the solid electrolyte layer 140 and the negative electrode 150 can be obtained. and By using different combinations of , we can get the current magnitude at different positions on the above interface.

[0086] The aforementioned hydrostatic stress distribution includes different third hydrostatic stress distributions. And the fourth hydrostatic stress distribution , then combined with formula (14), the ion flux associated with the solid electrolyte layer 140 may include different third ion fluxes and the fourth ion flux , so that the current density distribution of the solid electrolyte layer 140 is based on y and z There are two different expressions due to the difference in . That is, formula (20) can also be expressed as:

[0087]

[0088] S1-3: Calculate the negative electrode ion flux.

[0089] For negative electrode 150 ( x 4< x < x 5), its ion concentration satisfies Fick's diffusion law. For example, the ion concentration satisfies the following formula (21):

[0090]

[0091] Among them, the subscript Indicates the negative electrode, represents the ion concentration, represents the ion diffusion coefficient, Represents the boundary conditions. The boundary conditions for the above equation (21) can be expressed as the following equation (22), and the initial conditions can be expressed as the following equation (23):

[0092]

[0093] in, represents the negative electrode reaction rate, represents an external known current, Indicates the number of electrons participating in the reaction at the negative electrode, represents the Faraday constant, Represents the initial known concentration. Based on the above conditions, the ion concentration related to the negative electrode 150 can be obtained by solving Equation (21). expression.

[0094] The hydrostatic stress distribution corresponding to the negative electrode 150 can be determined based on the above-mentioned ion concentration and the Poisson's ratio, Young's modulus, and partial molar volume of the negative electrode 150. For example, the hydrostatic stress distribution can be expressed as the following formula (24):

[0095]

[0096] in, represents the hydrostatic stress distribution, represents Poisson's ratio, represents Young's modulus, represents the partial molar volume, Represents the initial stress of the negative electrode. After the relevant parameters are brought in, the hydrostatic stress distribution can be calculated.

[0097] The ion flux corresponding to the negative electrode 150 can be determined based on the ion concentration, the hydrostatic stress distribution, the ion diffusion coefficient, and the partial molar volume. For example, the ion flux can be expressed as follows (25):

[0098]

[0099] in, Represents the ion flux represents the ion concentration, Indicates the maximum storage ion concentration of the negative electrode, represents the ideal gas constant, which is 8.314 J / (mol·K). represents the temperature, which is 298.15 K. The initial conditions and boundary conditions for the above equation (25) can be expressed as follows:

[0100]

[0101] Among them, when located x = x 4, that is, at the interface between the solid electrolyte layer 140 and the negative electrode 150, the ion flux can be the quotient between the current density and the Faraday constant. x = xAt 5, which is the interface between the negative electrode 150 and the negative electrode current collector 160, the ion flux is zero. Based on the above conditions and the aforementioned ion concentration and hydrostatic stress distribution, equation (25) is solved to obtain the current density distribution related to the negative electrode 150. For example, the current density distribution related to the negative electrode 150 is It can be expressed as the following formula (28):

[0102]

[0103] in, can be expressed as the solved ion flux, represents the Faraday constant. Based on the above formula (28), when the value x = x 4 can be used to obtain the interface current at the interface between the negative electrode 150 and the negative electrode current collector 160. and By using different combinations of , we can get the current magnitude at different positions on the above interface.

[0104] In some implementations, the negative electrode 150 can be a lithium metal negative electrode. Since the negative electrode is lithium metal, the electrochemical reaction only occurs on the surface in contact with the solid electrolyte layer, and the remaining lithium metal will act as a current conductor. Therefore, the current will be transmitted in the form of a conductor inside the lithium metal negative electrode. The ion flux expression of the reaction on the surface of the lithium metal negative electrode is the same as the ion flux expression of the solid electrolyte membrane at this interface. In other words, the ion flux expression of the negative electrode 150 can be expressed by the solid electrolyte layer 140. x = x 4, the current density of the negative electrode 150 can be expressed as follows:

[0105]

[0106] Combining the expressions of the current density distribution of the above three components, the overall current density distribution of the solid-state battery 100 can be obtained, which can be expressed as the following formula (29):

[0107]

[0108] For the above calculation formulas, there are two boundaries for the electrochemical reaction in the positive electrode 120. One is the interface between the positive electrode 120 and the positive electrode current collector 110, and the other is the interface between the positive electrode 120 and the solid electrolyte layer 140. At the same time, on the side close to the solid electrolyte layer 140, the cross-sectional area of ​​the positive electrode 120 is reduced due to the insulating member 130. Therefore, for the positive electrode 120 ( x 1< x < x3) The ion reaction current at the interface and the internal ion diffusion are calculated based on the reaction chemical formula and stress distribution. For the solid electrolyte layer 140, ion diffusion occurs inside it, and there are two boundaries. One is the interface between the solid electrolyte layer 140 and the positive electrode 120, and the other is the interface between the solid electrolyte layer 140 and the negative electrode 150. The electrolyte conductivity is affected by pressure. Therefore, for the solid electrolyte layer 140 ( x 3< x < x 4) The stress-related ionic conductivity is calculated to obtain the internal ion diffusion. For the negative electrode 150, especially the lithium metal negative electrode, the electrochemical reaction occurs on its surface, and there is no intercalation reaction. The reaction only occurs on the negative electrode surface in contact with the solid electrolyte layer 140, and the rest can be regarded as a metal conductor. Therefore, for the negative electrode 150 ( x 4< x < x 5) Calculate the interfacial ion reaction current and the impedance change caused by the stress-related solid-solid interface contact area based on the reaction chemical formula and stress distribution.

[0109] S2: Based on the calculated ion fluxes of each part, calculate the interface currents at two locations where the negative electrode faces the central area of ​​the positive electrode and the edge area of ​​the positive electrode.

[0110] According to the current density distribution of each part obtained above, by determining x, y, z The interface current at each position inside the solid-state battery 100 can be obtained by selecting x = x 4, and select y and z By taking the value of , we can obtain the interface currents at two locations where the negative electrode faces the central area of ​​the positive electrode and the edge area of ​​the positive electrode.

[0111] For the battery 100, the currents at the boundary connections between the components are equal, and the sum of the voltages of the components is equal to the overall voltage of the battery. It can be expressed as the following formula (30):

[0112]

[0113] in, represents the potential, as well as represents the interfacial potential, namely, the interfacial potential between the positive electrode 120 and the solid electrolyte layer 140 and the interfacial potential between the solid electrolyte layer 140 and the negative electrode 150 . represents the SEI film polarization voltage. Based on the relationship between overpotential and current density, the Butler-Volmer equation can be used to solve the above overpotentials based on the current density. For example, the interfacial point position can be calculated based on the following equation (31):

[0114]

[0115] in, represents the current density, represents the current exchange density, represents the solid-solid interface contact factor, represents the transfer coefficient.

[0116] In order to evaluate battery performance, the average overpotential can be used to replace the overpotential. For example, it can be based on the following formula (32):

[0117]

[0118] The following is an illustrative example of the above process using a specific implementation process. It should be noted that the following content is only for illustration and does not limit the present application.

[0119] Using all-solid-state single-chip battery, the battery parameters are as follows:

[0120] Positive electrode size: 20mm 20mm 130 , Insulation component outer ring size: 20mm 20mm 25 , Insulation component inner ring size: 19mm 19mm 25 , solid electrolyte membrane size: 23mm 23mm 30 , negative electrode size: 23mm 23mm 10 Chemical system: NMC / Li. Young's modulus of the positive electrode: 400MPa, Young's modulus of the solid electrolyte membrane: 900MPa, Young's modulus of lithium metal: 2GPa, Young's modulus of the insulating component: 900MPa. The Poisson's ratio of the positive electrode is 0.25, the Poisson's ratio of the solid electrolyte membrane is 0.33, and the Poisson's ratio of the negative electrode is 0.34. The diffusion coefficient of the positive electrode is: The positive electrode ion conductivity is 3.8S / m, the electrolyte ion conductivity is a function related to the stress distribution, the positive electrode partial molar volume strain is a function related to the degree of particle lithiation, and the ideal gas constant R is 8.31J / (K mol), Faraday constant F is 96485C / mol, temperature T is 298.15K, external pressure: 5MPa.

[0121] Indicates the positive electrode reaction rate, in this embodiment, 5e -10 m / s, Indicates the number of electrons participating in the reaction at the positive electrode, which is 1 in this embodiment. Indicates the maximum storage ion concentration of the positive electrode. In this embodiment, it is 22860 mol / m 3 ;

[0122] represents the transfer coefficient, which is 0.5 in this embodiment.

[0123] The overall stress distribution of the battery satisfies:

[0124]

[0125] Since it is in static equilibrium, it can be simplified as:

[0126]

[0127] At the continuous interface , brought into the model, in ( x 2 <x<x 3) When satisfied:

[0128]

[0129] Ignoring the size edge effect, the upper side of the insulating component can be calculated by external pressure, interface size, Young's modulus, and Poisson's ratio ( x 1 <x<x 2) The initial stress of the positive electrode is , parallel to the insulating member ( x 2 <x<x 3) The initial stress of the positive electrode is The initial stress of the solid electrolyte membrane is in the area opposite to the insulating component and the area outside it. The initial stress of the solid electrolyte membrane is in the area facing the internal positive electrode. , the internal initial stress of the negative electrode is , the external initial stress of the negative electrode is .

[0130] 1. For the positive electrode, Fick's diffusion law is satisfied, that is:

[0131]

[0132] The coefficient and wave number It can be determined based on boundary conditions and initial conditions.

[0133] The hydrostatic stress distribution is:

[0134] when( x 1 <x<x 2) Time:

[0135]

[0136] when( x 2 <x<x 3) Time:

[0137]

[0138] Substitute the hydrostatic stress distribution and concentration distribution into the flux formula:

[0139]

[0140] Right now:

[0141]

[0142] Then the current density distribution of the positive electrode is:

[0143]

[0144] 2. For the solid electrolyte membrane, similar to the positive electrode, the ion flux expression can be calculated based on the hydrostatic stress distribution and concentration distribution.

[0145] Concentration distribution:

[0146]

[0147] The coefficient and wave number It can be determined based on the boundary conditions and initial conditions. The boundary condition is that at the x=x3 interface, the ion flux of the positive electrode and the solid electrolyte membrane is the same. The initial condition is that the ion concentration distribution at the initial moment is the initial known concentration. .

[0148] Hydrostatic stress distribution:

[0149] In the area where the solid electrolyte membrane faces the positive electrode:

[0150]

[0151] In the area other than the solid electrolyte membrane facing the positive electrode:

[0152]

[0153] The ion flux expression is as follows:

[0154]

[0155] The current density distribution of the solid electrolyte separator is:

[0156]

[0157] 3. For the ion flux expression of the negative electrode, since the negative electrode is lithium metal and the electrochemical reaction only occurs on the surface in contact with the solid electrolyte separator, the remaining lithium metal will act as a current conductor. Therefore, the current will be transmitted in the form of a conductor inside the lithium metal negative electrode. The ion flux expression for the reaction on the surface of the lithium metal negative electrode is the same as the ion concentration flux expression of the solid electrolyte separator at this interface, that is:

[0158] Concentration distribution:

[0159]

[0160] To sum up, for the entire lithium metal NMC solid-state battery, in the region where electrochemical reactions and ion diffusion occur, that is, x1 < x < x4, the current distribution satisfies:

[0161]

[0162] The input current is 0.06 A. Substituting it back into the formula, the current density at the negative electrode interface can be obtained. The current density in the region directly opposite to the center of the positive electrode is 150.9 A / m 2 , and the current density in the region directly opposite to the edge of the positive electrode is 344.1 A / m 2 .

[0163] Battery nail penetration test:

[0164] The storage battery is subjected to a cycle performance test for 50 cycles according to the charge and discharge conditions of GB / T31484:

[0165] 1. Charge at a constant current of 1C until the specified charge termination voltage is reached, then switch to constant voltage charging, and stop charging when the charging current drops to 0.05C. After charging, let it stand for 1h;

[0166] 2. In an environment of 22°C ± 5°C, a high-temperature resistant steel needle with a diameter of 5 mm and a conical angle of 30° at the tip penetrates the battery in a direction perpendicular to the battery plate at a speed of (25 ± 5) mm / s, and the steel needle remains in the battery;

[0167] 3. Observe for 2h at the test environment temperature.

[0168] If there is no fire or explosion, it means passing; if there is a fire or explosion, it means failing.

[0169] The calculation results obtained by changing the Young's modulus of the insulating member can be referred to in Table 1 below:

[0170] Table 1 Current density calculation results

[0171]

[0172] When the Young's modulus of the insulating component is 100 MPa, the current density distribution diagram and local enlarged diagram of the negative electrode interface can be referred to Figure 3 When the Young's modulus of the insulating component is 400MPa, the current density distribution diagram and local enlarged diagram of the negative electrode interface can be referred to Figure 4 When the Young's modulus of the insulating component is 900MPa, the current density distribution diagram and local enlarged diagram of the negative electrode interface can be referred to Figure 5 .

[0173] It can be seen that the use of insulating parts with a smaller Young's modulus can effectively reduce the negative electrode interface current and improve the safety performance of the battery. This is consistent with the battery performance trend in the actual battery evaluation process. The use of insulating parts with a lower Young's modulus can significantly improve the safety performance of the battery and avoid the formation of dendrites.

[0174] The above conclusions are consistent with the actual safety test conclusions of the battery.

[0175] The interface current calculation method disclosed in this application can accurately calculate the interface current of batteries (especially new solid-state batteries with insulating components), providing an important basis for battery design and production.

[0176] It should be noted that the above Figure 1 The description of each step in the description is only for example and explanation, and does not limit the scope of application of this specification. For those skilled in the art, under the guidance of this specification, Figure 1 Various modifications and changes may be made to the various steps in the present invention. However, these modifications and changes are still within the scope of this specification.

[0177] The present application also discloses a battery interface current calculation device. The interface current calculation device can be used to perform the following Figure 2 For details of the steps shown in , please refer to the corresponding drawings. Figure 6 is an exemplary module diagram of an interface current calculation device according to some embodiments of the present application, such as Figure 6 As shown, the interface current calculation device 600 may include a first determination module 610 , a second determination module 620 and a third determination module 630 .

[0178] The first determination module 610 can be configured to determine the ion concentration and the hydrostatic stress distribution. The first determination module 610 can determine the equation satisfied by the ion concentration based on Fick's diffusion law and combine relevant initial conditions and boundary conditions to determine the specific expression of the ion concentration. The first determination module 610 can also determine the corresponding hydrostatic stress distribution based on the Poisson's ratio, Young's modulus, and partial molar volume of the component.

[0179] The second determination module 620 may be configured to determine the ion flux using the hydrostatic stress distribution and the ion concentration. The second determination module 620 may determine the ion flux based on the ion concentration, the hydrostatic stress distribution, the ion diffusion coefficient, and the partial molar volume.

[0180] The third determination module 630 may determine the interface current based on the ion flux. The third determination module 630 may determine the current density distribution using the ion flux, for example, by taking the product of the ion flux and the Faraday constant as the current density distribution.

[0181] For other descriptions of the above components, please refer to this application Figure 1-Figure 5 part.

[0182] It should be understood that Figure 6 The illustrated system and its modules can be implemented in various ways. For example, in some embodiments, the system and its modules can be implemented using hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic, while the software portion can be stored in memory and executed by an appropriate instruction execution system, such as a microprocessor or specially designed hardware. Those skilled in the art will appreciate that the above-described methods and systems can be implemented using computer-executable instructions and / or contained in processor control code, such as provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The system and its modules of the present application can be implemented not only using hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips or transistors, or programmable hardware devices such as field programmable gate arrays or programmable logic devices, but can also be implemented using software, such as executed by various types of processors, or a combination of the above-described hardware circuits and software (e.g., firmware).

[0183] It should be noted that the above description of the modules is for convenience of description only and does not limit the present application to the scope of the embodiments. It is understandable that for those skilled in the art, after understanding the principle of the system, it is possible to arbitrarily combine the modules or form a subsystem connected to other modules without deviating from this principle. For example, the first determination module 610, the second determination module 620, and the third determination module 630 are the same determination module. For another example, the modules can share a storage module, or each module can have its own storage module. Variations such as these are all within the scope of protection of the present application.

[0184] The present application also provides a computing device. Figure 7 The example block diagram of the computing device shown in FIG. 700 according to some embodiments of the present application. The computing device 700 may include a computer program product for implementing the processes described in the embodiments of the present application (for example, Figure 1-Figure 5 ) or systems (e.g. Figure 6 ). For example, the computing device 700 can be implemented by hardware, software program, firmware or a combination thereof. For convenience, Figure 7 Only one computing device is drawn in the figure, but the computing functions related to the process and / or system / apparatus described in the embodiments of the present application can be implemented in a distributed manner by a group of similar platforms to disperse the processing load of the system.

[0185] In some embodiments, computing device 700 may include a processor 710, memory 720, input / output components 730, and a communication port 740. In some embodiments, processor (e.g., CPU) 710 may execute program instructions in the form of one or more processors. In some embodiments, memory 720 may include various forms of program memory and data storage, such as a hard disk, read-only memory (ROM), random access memory (RAM), etc., for storing various data files processed and / or transmitted by the computer. In some embodiments, input / output components 730 may support input / output between computing device 700 and other components. In some embodiments, communication port 740 may be connected to a network for data communication. Exemplary computing devices may include program instructions stored in read-only memory (ROM), random access memory (RAM), and / or other types of non-transitory storage media, executed by processor 710. The methods and / or processes of embodiments of the present application may be implemented in the form of program instructions. Computing device 700 may also receive the programs and data disclosed herein via network communications.

[0186] For ease of understanding, Figure 7Only one processor is shown in the figure as an example. However, it should be noted that the computing device 700 in the embodiment of the present application may include multiple processors, so the operations and / or methods implemented by one processor described in the embodiment of the present application may also be implemented jointly or independently by multiple processors. For example, if in the present application, the processor of the computing device 700 performs operations A and B, it should be understood that operations A and B may also be performed jointly or independently by two different processors of the computing device 700 (for example, the first processor performs operation A, the second processor performs operation B, or the first and second processors perform operations A and B jointly).

[0187] While the basic concepts have been described herein, it will be apparent to those skilled in the art that the detailed disclosure herein is merely illustrative and does not constitute a limitation of the present application. Although not expressly provided herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are suggested herein and remain within the spirit and scope of the exemplary embodiments of the present application.

[0188] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this application does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0189] Similarly, it should be noted that, in order to simplify the description of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment or its description. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, the features of an embodiment may be fewer than all the features of the individual embodiments disclosed above.

[0190] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other variations may also fall within the scope of this application. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this application may be considered consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly introduced and described in this application.

Claims

1. A method for calculating the interfacial current of an all-solid-state battery, the battery comprising the following multiple components stacked in sequence: a positive electrode current collector, a positive electrode, a solid electrolyte layer, a negative electrode, an insulating member, and a negative electrode current collector; the insulating member is annularly arranged and covers a portion of the positive electrode periphery near the solid electrolyte layer in a contact pressure manner; the positive electrode comprises a first portion not covered by the insulating member and a second portion covered by the insulating member; the solid electrolyte layer comprises a third portion corresponding to the second portion and a fourth portion located outside the third portion; The second portion is in contact with the third portion; Characterized in that, the interface current calculation method includes: Step S1. Calculating the ion flux of each part; Step S1-1. Calculating the stress distribution of the first and second parts of the positive electrode respectively, and calculating the positive electrode ion flux based on the stress distribution; Step S1-2. Calculating the stress distribution of the third and fourth parts of the solid electrolyte layer respectively, and calculating the ion flux of the solid electrolyte layer based on the stress distribution; Step S2. Based on the ion flux calculated in step S1, calculate the interface currents at two locations where the negative electrode faces the central region of the positive electrode and the edge region of the positive electrode.

2. The method for calculating interface current according to claim 1, wherein: The second portion of the positive electrode accounts for 1%-10% of the positive electrode.

3. The method for calculating interface current according to claim 1, wherein: The step S1 further includes step S1-3. calculating the negative electrode ion flux, where the negative electrode is metallic lithium.

4. The method for calculating interface current according to claim 1, wherein: The stress distribution of the second part of the positive electrode satisfies: ;in, is the area of ​​the second part, is the area of ​​the insulating member, is the positive electrode Young's modulus, is the Young's modulus of the insulating component, is the external load.

5. The method for calculating interface current according to claim 1, wherein: The step S2 further includes: determining a current density distribution using the ion flux; The interface current is determined based on the current density distribution.

6. The method for calculating interface current according to claim 1, wherein: The Young's modulus of the insulating member is different from the Young's modulus of the positive electrode.

7. A battery interface current calculation system, the calculation system comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the steps of the method for calculating the interface current of a battery according to any one of claims 1 to 6 are implemented.

8. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for calculating the interface current of a battery according to any one of claims 1 to 6 are implemented.

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