A prediction method and system for void evolution in all-solid-state lithium metal batteries

Abstract

The present invention belongs to the technical field related to all-solid-state lithium metal batteries, and is a prediction method and system for the evolution of voids in all-solid-state lithium metal batteries, comprising the following steps: meshing the lithium metal electrode, with the mesh nodes being lithium atoms or vacancies, applying stacking pressure from bottom to top at the bottom of the lithium metal electrode, and changing the working temperature and stacking pressure of the calculation domain at the same time, thereby adjusting the size of the void; constructing a phase field order parameter equation, concentration equation, electrochemical equation, and mechanical equation that describe the evolution of the void; establishing an optimization model with the goal of minimizing the void area, solving the optimization model, and obtaining the relationship between the stacking pressure and the working temperature and the void area, thereby realizing the prediction of the evolution of the void. Through the present invention, the quantification of the evolution of voids in all-solid-state lithium metal batteries with different stacking pressures and different working temperatures is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field related to all-solid-state lithium metal batteries, and more specifically, relates to a method and system for predicting void evolution in an all-solid-state lithium metal battery. Background Art

[0002] All-solid-state lithium metal batteries are considered to be the most promising next-generation energy storage system. Solid electrolytes have intrinsic safety characteristics compared to traditional liquid electrolytes. At the same time, lithium metal anodes have extremely low chemical potentials and extremely high specific capacities (3860 mAh g -1 ), has always been regarded as the most ideal anode material. The combination of solid electrolyte and lithium metal anode is expected to achieve high energy density and high safety for industrial applications.

[0003] However, due to the lack of fluidity of solid electrolytes, solid-solid contact at the electrode / electrolyte interface has always been a thorny problem. The tiny gaps or impurities at the electrode / electrolyte interface cause the generation of Kirkendall voids at the interface during lithium stripping. The current concentration formed around the voids exacerbates the growth of the voids, causing the interface contact to deteriorate, resulting in high interface impedance and causing interface instability. Excessive growth of voids can also cause the electrode to completely lose contact with the electrolyte. In the subsequent electroplating process, lithium atoms are unevenly deposited at the interface, and lithium atoms are accelerated to deposit at the edge of the voids, inducing the nucleation and growth of lithium dendrites. Lithium dendrites penetrate into the solid electrolyte and eventually penetrate the electrolyte, causing short circuit failure in the battery.

[0004] Reasonable regulation of stacking pressure and operating temperature is an important factor in inhibiting the formation and growth of voids. Stacking pressure can drive creep deformation of lithium metal electrodes. On the one hand, creep can reduce the void nucleation barrier controlled by the interface overpotential. On the other hand, lithium metal undergoes creep deformation due to the dislocation climbing mechanism, which reduces the energy barrier for vacancy diffusion and helps to transfer vacancies to the lithium metal body more quickly. However, excessive stacking pressure also poses the risk of lithium dendrites penetrating the solid electrolyte, especially the softer sulfide electrolyte. Another feasible way to achieve void suppression is to increase the operating temperature. The compressive yield strength of lithium is extremely sensitive to temperature, and the creep mechanism of lithium is particularly evident at high temperatures.

[0005] However, at present, the experimental and simulation studies on the cycling performance of all-solid-state lithium metal battery interfaces are incomplete. Most experimental studies rely on monitoring the battery's overpotential and interface impedance to characterize the interface contact state and indirectly describe the interface void evolution. The method used in the simulation study is too simplified to accurately describe the interface contact condition. Specifically, there is a lack of clear technical support for how stacking pressure and operating temperature drive creep and diffusion to regulate void evolution. Summary of the invention

[0006] In response to the above defects or improvement needs of the prior art, the present invention provides a method and system for predicting void evolution in an all-solid-state lithium metal battery, which solves the problem that void evolution in an all-solid-state lithium metal battery cannot be modulated by stacking pressure and operating temperature.

[0007] To achieve the above object, according to one aspect of the present invention, a method for predicting void evolution in an all-solid-state lithium metal battery is provided, the method comprising the following steps:

[0008] Constructing a computational domain consisting of a lithium metal electrode and a solid electrolyte, in which the lithium metal electrode is arranged at the bottom, the solid electrolyte is attached to the lithium metal electrode, there is a cavity at the contact between the lithium metal electrode and the solid electrolyte, and roller support is arranged around the solid electrolyte and the lithium metal electrode except for the bottom;

[0009] The lithium metal electrode is meshed, with the mesh nodes being lithium atoms or vacancies, and stacking pressure is applied from bottom to top at the bottom of the lithium metal electrode, while the working temperature and stacking pressure of the calculation domain are changed to adjust the size of the void; the phase field order parameter equation, concentration equation, electrochemical equation and mechanical equation of the void evolution are constructed;

[0010] An optimization model with the goal of minimizing the void area is established, and the phase field order parameter equation, concentration equation, mechanical equation, electrochemical equation and boundary conditions of the computational domain are combined to solve the optimization model, and the relationship between the stacking pressure and the operating temperature and the void area is obtained, so as to realize the prediction of void evolution.

[0011] Further preferably, the phase field order parameter equation is as follows:

[0012] ;

[0013] μ ζ =δA / δζ

[0014] Where t is time, u is the displacement field of the lithium metal electrode, is the velocity field, L is the phase field mobility coefficient, μ ζ is the chemical potential of the lithium lattice, A is the Helmholtz free energy of the lithium metal electrode, and ζ is the phase field order parameter.

[0015] Further preferably, the relationship between the Helmholtz free energy of the lithium metal electrode is as follows:

[0016] ;

[0017] Where A is the Helmholtz free energy, A bulk is the Helmholtz free energy of the lithium metal electrode bulk, A interfaceis the Helmholtz free energy at the lithium metal / void interface, c L is the lattice concentration, R is the universal gas constant, T is the temperature, θ 0 is the proportion of lithium atoms at the initial moment, V is the electrode volume, ζ is the non-conservative phase field order parameter, W is the barrier height, g(ζ) is the double well function, κ is the gradient energy coefficient, θ m is the proportion of lithium atoms.

[0018] Further preferably, the concentration equation is as follows:

[0019] ;

[0020] D T =D ref exp[-E(1 / T-1 / T ref ) / k B ]

[0021] Among them, c Li is the lithium atomic concentration, D T is the diffusion coefficient at temperature T, D ref is the reference diffusion coefficient, E is the diffusion energy barrier, k B is the Boltzmann constant, T ref is the reference temperature, μ Li is the chemical potential of lithium atoms and R is the universal gas constant.

[0022] Further preferably, the chemical potential μ of the lithium atom is Li Calculate according to the following relationship:

[0023] μ Li =-RTln[θ 0 / (1-θ 0 )]+RTln[θ m / (1-θ 0 )]-(Ω Li -Ω v )σ h

[0024] Among them, Ω Li is the molar volume of lithium atoms, σ h is the hydrostatic pressure, θ m is the proportion of lithium atoms, θ 0 is the proportion of lithium atoms at the initial moment.

[0025] Further preferably, the electrochemical equation is as follows:

[0026] ;

[0027] Among them, σ SSE and are the conductivity and potential of the electrolyte, σ Li and are the conductivity and electrode potential of the lithium metal electrode, respectively, and f(ζ) is the interpolation function.

[0028] Further preferably, the mechanical equation is as follows:

[0029] ;

[0030] Where C is the elastic stiffness tensor of the lithium metal electrode, C = C[h(ζ)E Li ,υ Li ], h(ζ) is the interpolation, E li is the Young's modulus of lithium metal, υ Li is the Poisson's ratio of lithium metal, ε el is the elastic strain, ε is the total strain, and ε cr is the creep strain, ε ch is the chemical strain, u is the displacement, c Li is the lithium atomic concentration, c ref is the reference lithium concentration, Ω Li is the molar volume of lithium atoms, Ω v is the molar volume of the vacancy, I is the second-order unit tensor, A is the pre-exponential factor, σ mises is the von Mises stress, σ ref is the reference stress, n is the power law exponent, Q is the creep activation energy, T ref is the reference temperature, T is the temperature, and R is the universal gas constant.

[0031] Further preferably, the boundary conditions of the calculation domain are as follows:

[0032] ;

[0033] Where n is the normal direction, L is the phase field migration coefficient, κ is the gradient energy coefficient, ζ is the phase field order parameter, and D T is the temperature-dependent diffusion coefficient, c Li is the lithium atomic concentration, R is the universal gas constant, T is the temperature, μ Li is the chemical potential of lithium atoms, i 0 is the reference exchange current density, is the electrode potential, is the electrolyte potential, C is the elastic stiffness tensor, ε el is the elastic strain, p is the applied stack pressure, u is the displacement field, σ SSE is the electrolyte conductivity, f(ζ) is the interpolation function, σ Li is the conductivity of lithium metal and i is the applied current density.

[0034] Further preferably, the relationship between the cavity area is as follows:

[0035] S=∫ Ω ζ<0.5 dxdy

[0036] Where S is the area of ​​the void, ζ is the phase field order parameter, Ω is the computational domain, x is the horizontal coordinate, and y is the vertical coordinate.

[0037] According to another aspect of the present invention, a prediction system for void evolution in an all-solid-state lithium metal battery is provided, the system comprising an actuator for executing the above-mentioned method for predicting void evolution in an all-solid-state lithium metal battery.

[0038] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0039] 1. The present invention constructs a computational domain consisting of a metal electrode and a solid electrolyte, applies stacking pressure at the bottom of the computational domain and changes the working temperature to adjust the size of the void, and finally constructs an optimization model for the void area. The optimization model is solved to obtain the quantitative relationship between stacking pressure and temperature and the void size, thereby realizing the regulation of the void evolution process.

[0040] 2. The present invention can control the evolution of voids by using external physical fields (such as stacking pressure and operating temperature) by constructing an optimization model. Compared with the previous method of changing material properties, this is a more cost-effective strategy without the introduction of new materials and new processes.

[0041] 3. The present invention comprehensively considers lithium stripping and deposition, bulk diffusion and surface diffusion, creep deformation, lattice distortion, and nucleation and annihilation of vacancies by constructing phase field order parameter equations, concentration equations, mechanical equations, and electrochemical equations, and can capture the void evolution during a complete stripping / electroplating cycle.

[0042] 4. The mechanical equation constructed in the present invention takes into account the important role of creep effect in the operation of all-solid-state lithium metal batteries. Higher stacking pressure and higher operating temperature can initiate stronger creep deformation, inhibit void expansion and accelerate void filling, achieve void annihilation, and improve interface contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of a method for predicting void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention.

[0044] Figure 2 A schematic diagram of the model construction in the method for predicting void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention.

[0045] Figure 3 A schematic diagram of the geometric structure, boundary conditions and initial value settings in the method for predicting void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention.

[0046] Figure 4 This is a rendering of the void evolution calculated in the prediction method for void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention.

[0047] Figure 5 A graph of changes in the normalized area of ​​voids calculated in the method for predicting void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention.

[0048] Figure 6 A relationship diagram between the void healing rate, the operating temperature and the stacking pressure constructed in the method for predicting void evolution in an all-solid-state lithium metal battery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] A method to predict the interfacial cycling performance of all-solid-state lithium metal batteries, such as Figure 1 and Figure 2 As shown, the steps are:

[0051] S1: construct a computational domain consisting of a lithium metal electrode and a solid electrolyte, in which the lithium metal electrode is arranged at the bottom, the solid electrolyte is attached to the lithium metal electrode, there is a cavity at the contact between the lithium metal electrode and the solid electrolyte, and roller support is arranged around the solid electrolyte and the lithium metal electrode except the bottom;

[0052] Specifically, a computational domain consisting of a lithium metal electrode and a solid electrolyte is constructed in S3, describing a small area near the lithium metal electrode / solid electrolyte interface. Figure 3 As shown, in this embodiment, the width of the electrode and the electrolyte are W , the height is H , the scale is in the micrometer level. At the initial moment, there is a radius of r The initial lithium ratio in the void region is 0, and the initial lithium ratio in the lithium metal region is θ 0 .

[0053] S2: Meshing the lithium metal electrode, with the mesh nodes being lithium atoms or vacancies, applying a stacking pressure from bottom to top at the bottom of the lithium metal electrode, and changing the working temperature and stacking pressure of the computational domain to adjust the size of the void; constructing a phase field order parameter equation, a concentration equation, an electrochemical equation, and a mechanical equation to describe the evolution of the void;

[0054] Specifically, Figure 2 As shown, there is a coupling relationship between the different physical fields established. First, based on the established lithium electrode lattice network, the chemical potential of lithium atoms and the chemical potential of the lattice are obtained. The chemical potential of lithium atoms is input into the concentration equation. The concentration field is affected by the local current density of the electrode / electrolyte interface calculated by the electrochemical equation, and is also affected by the hydrostatic pressure calculated by the mechanical equation. The lithium atom concentration distribution calculated by the concentration field reacts to the mechanical field.

[0055] (1) Phase field order parameter equation

[0056] The phase field order parameter ζ is used to track the lithium metal / void interface, ζ=1 represents lithium metal, ζ=0 represents void, and the phase field order parameter equation is:

[0057] (1)

[0058] Where t is time, u is the displacement field, is the velocity field, L is the phase field mobility coefficient, μ ζ is the chemical potential of the lithium lattice, which is obtained by taking the partial derivative of the Helmholtz free energy A with respect to the phase field order parameter ζ. The phase field order parameter is driven by the Helmholtz free energy of the electrode and affected by the electrode deformation. The chemical potential of the lithium lattice is expressed as:

[0059] μ ζ =δA / δζ (2)

[0060] Specifically, the lithium metal electrode is considered to be a lattice network composed of lithium lattices, and the lattice points are occupied by lithium atoms or vacancies. The Helmholtz free energy is:

[0061] A=A bulk +A interface (3)

[0062] (4)

[0063] (5)

[0064] Where A is the Helmholtz free energy, A bulk represents the Helmholtz free energy of the lithium metal electrode bulk, A interface is the Helmholtz free energy at the lithium metal / void interface, c Lrepresents the lattice concentration, R represents the universal gas constant, T represents the temperature, θ 0 represents the proportion of lithium atoms at the initial moment, V represents the volume of the lithium metal electrode, ζ represents the non-conservative phase field order parameter, W represents the barrier height, g(ζ) represents the double well function, and in this embodiment, g(ζ)=ζ is preferably 2 (1-ζ) 2 , κ represents the gradient energy coefficient, θ m = h(ζ)c Li / c L represents the proportion of lithium atoms, where h(ζ) is an interpolation function. In this embodiment, h(ζ)= ζ is preferably 3 (6ζ 2 -15ζ+10), c Li Represents the lithium atomic concentration.

[0065] Specifically, θ 0 It can be expressed as:

[0066] θ 0 =1-exp[-h v / (RT)](6)

[0067] Among them, h v is the molar enthalpy of vacancy formation in lithium metal.

[0068] From formulas (2) to (6), we can get:

[0069] (7)

[0070] Where A is the Helmholtz free energy, Ω L is the molar volume of the lithium lattice, Ω v is the molar volume of the vacancy, g'(ζ) represents the derivative of the double-well function g(ζ), and h'(ζ) represents the derivative of the interpolation function h(ζ).

[0071] Substituting formula (7) into formula (1), we obtain:

[0072] (8)

[0073] (2) The concentration equation describes the concentration of lithium atoms in the lithium electrode. The diffusion coefficient is affected by temperature. The concentration equation of lithium atoms in the lithium metal electrode is:

[0074] (9)

[0075] Among them, D T =D ref exp[-E(1 / T-1 / T ref ) / k B ] represents the diffusion coefficient when the temperature is T, Dref represents the reference diffusion coefficient, E represents the diffusion energy barrier, k B represents the Boltzmann constant, T ref represents the reference temperature, μ Li is the chemical potential of lithium atoms. According to formulas (3) to (5), the Helmholtz free energy A is related to the concentration of lithium atoms c Li Taking partial derivatives, we get:

[0076] μ Li =δA / δc Li =-RTln[θ 0 / (1-θ 0 )]+RTln[θ m / (1-θ 0 )]-(Ω Li -Ω v )σ h (10)

[0077] Among them, Ω Li represents the molar volume of lithium atoms, σ h represents the hydrostatic pressure, σ h =(trσ) / 3, σ represents the stress tensor, and trσ represents the trace of the stress tensor.

[0078] (3) The electrochemical equation is expressed as:

[0079] (11)

[0080] (12)

[0081] Among them, σ SSE and denote the conductivity and potential of the electrolyte, σ Li and denote the conductivity and electrode potential of the lithium metal electrode, respectively; f(ζ) denotes an interpolation function for ensuring that there is no conductivity inside the void; specifically, in this embodiment, the interpolation function f(ζ) is preferably f(ζ)=16ζ 15 -15ζ 16 .

[0082] (4) The mechanical equation can be expressed as:

[0083] (13)

[0084] Where C = C[h(ζ)E Li ,υ Li ], represents the elastic stiffness tensor of the lithium metal electrode, υ Li represents the Poisson's ratio of lithium metal, E Li represents the Young's modulus of lithium metal, εel is the elastic strain, expressed as:

[0085] ε el= ε-ε cr -ε ch (14)

[0086] Where ε represents the total strain, , u represents displacement, ε ch represents chemical strain, ε cr represents the creep strain.

[0087] Due to the different partial molar volumes of lithium atoms and lithium vacancies, when lithium atoms diffuse to empty lattice points or lithium atoms escape to form new vacancies, the lattice will be distorted. The strain caused by the migration of lithium atoms in the electrode is expressed by the chemical strain ε ch express:

[0088] ε ch =(c Li -c ref )(Ω Li -Ω v )I / 3 (15)

[0089] Among them, c ref As the reference lithium concentration, the lithium concentration at the initial moment is generally taken as c ref =h(ζ 0 )θ 0 / Ω L , 0 represents the order parameter distribution at the initial moment, and I is the second-order unit tensor.

[0090] Lithium metal has a high homogenous temperature and a very low compressive yield strength, and is prone to creep deformation when subjected to stress. The power law creep constitutive model is used to calculate the creep strain ε cr The strain rate dε cr / dt, expressed as:

[0091] dε cr / dt=A(σ mises / σ ref ) n exp[-Q(1 / T-1 / T ref ) / R](16)

[0092] Among them, A is the pre-exponential factor, σ mises is the von Mises stress, σ mises =(3 / 2) 0.5 |σ dev |,σ dev is the deviatoric stress, σ dev =σ-(trσ) / 3,σ refis the reference stress, n is the power law exponent, and Q is the creep activation energy.

[0093] S3: Establish an optimization model with the goal of minimizing the void area, solve the optimization model by combining the phase field order parameter equation, concentration equation, mechanical equation, electrochemical equation and the boundary conditions of the calculation domain, and obtain the relationship between the stacking pressure and the working temperature and the void area, so as to realize the prediction of void evolution.

[0094] (1) Boundary conditions of the computational domain

[0095] In the phase field, zero flux is set for all boundaries, expressed as:

[0096] (17)

[0097] Where n represents the normal direction.

[0098] In the concentration field, for the electrode / electrolyte interface, the boundary condition is expressed as:

[0099] (18)

[0100] Among them, i 0 represents the reference exchange current density.

[0101] For the remaining boundaries, zero flux is set, expressed as:

[0102] (19)

[0103] In the mechanical field, the stack pressure is applied to the lower surface, which is expressed as:

[0104] (20)

[0105] Wherein, p represents the applied stacking pressure, which is preferably 0-5 MPa.

[0106] The remaining boundaries are restrained by roller supports, expressed as:

[0107] (twenty one)

[0108] In the electrochemical field, the grounding boundary condition is applied to the lower surface, which is expressed as:

[0109] (twenty two)

[0110] The left and right sides are insulating boundaries, expressed as:

[0111] (twenty three)

[0112] (twenty four)

[0113] The above indicates the applied current flux i, which is expressed as:

[0114] (25)

[0115] Wherein, i is the applied current density, i>0 indicates an electroplating process, and i<0 indicates a stripping process. In the present invention, stripping and electroplating are achieved by setting different current boundaries, and electroplating and stripping are a continuous process.

[0116] In this embodiment, the current density i is preferably 1 mA / cm 2 , first stripping for 15000s, followed by continuous electroplating for the same time.

[0117] In this embodiment, the operating temperature of the battery is preferably between 20-80°C.

[0118] (2) The phase field order parameter equation, concentration equation, mechanical equation, electrochemical equation and boundary conditions are input into the finite element calculation software to obtain the effects of different stacking pressures and operating temperatures on the evolution of interface voids.

[0119] The calculation area is discretized using triangular meshes, and the meshes are encrypted in the void evolution area and the electrode electrolyte interface area to improve the calculation accuracy. Specifically, the maximum characteristic length of the meshes in the void evolution area and the electrode electrolyte interface area is preferably 0.1 μm, and the number of triangular meshes obtained is about 40,000, corresponding to about 1.6 million degrees of freedom. The separation solver is used for solving, and the upper and lower limits of the phase field order parameter are set.

[0120] (3) Using the constructed optimization model, the changes of voids during the stripping electroplating process can be obtained, such as Figure 4 shown.

[0121] The contour line of the phase field order parameter ζ=0.5 is defined as the boundary of the void, and the area S of the void can be expressed as:

[0122] S=∫ Ω ζ<0.5 dxdy (26)

[0123] Where Ω is the computational domain, x is the horizontal coordinate, and y is the vertical coordinate.

[0124] Comparing the area at the end of the loop with the initial area, we can get the normalized area of ​​the hole, expressed as:

[0125] §=S / S 0 (27)

[0126] Among them, S 0is the area of ​​the hole at the initial moment, § is the normalized area of ​​the hole, and its change over time is as follows: Figure 5 shown.

[0127] The area of ​​the voids can be used to reflect the cycle performance of the battery.

[0128] The healing rate η of the cavity after one cycle can also be obtained, expressed as:

[0129] η=(1-S final / S 0 )×100% (28)

[0130] Among them, S final is the area of ​​the hole at the last moment.

[0131] The void healing rate is used to describe the interface contact situation. The relationship between the void healing rate and different operating temperatures and stacking pressures is as follows: Figure 6 As shown, at lower operating temperatures and lower stacking pressures, the interfacial contact will deteriorate, while at higher stacking pressures and higher operating temperatures, the interfacial contact will heal quickly. Based on this graph, it can provide a basis for finding the optimal operating window for all-solid-state lithium metal batteries in industrial applications.

[0132] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for predicting void evolution in an all-solid-state lithium metal battery, characterized in that: The prediction method includes the following steps: Constructing a computational domain consisting of a lithium metal electrode and a solid electrolyte, in which the lithium metal electrode is arranged at the bottom, the solid electrolyte is attached to the lithium metal electrode, there is a cavity at the contact between the lithium metal electrode and the solid electrolyte, and roller support is arranged around the solid electrolyte and the lithium metal electrode except for the bottom; The lithium metal electrode is meshed, with the mesh nodes being lithium atoms or vacancies, and stacking pressure is applied from bottom to top at the bottom of the lithium metal electrode, while the working temperature and stacking pressure of the calculation domain are changed to adjust the size of the void; the phase field order parameter equation, concentration equation, electrochemical equation and mechanical equation of the void evolution are constructed; An optimization model with the goal of minimizing the void area is established, and the phase field order parameter equation, concentration equation, mechanical equation, electrochemical equation and boundary conditions of the computational domain are combined to solve the optimization model, and the relationship between the stacking pressure and the operating temperature and the void area is obtained, so as to realize the prediction of void evolution.

2. The method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1, characterized in that: The phase field order parameter equation is as follows: ; ; Where t is time, u is the displacement field of the lithium metal electrode, is the velocity field, L is the phase field mobility coefficient, μ ζ is the chemical potential of the lithium lattice, A is the Helmholtz free energy of the lithium metal electrode, and ζ is the phase field order parameter.

3. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 2, characterized in that: The relationship between the Helmholtz free energy of the lithium metal electrode is as follows: A=A bulk +A interface ; Where A is the Helmholtz free energy, A bulk is the Helmholtz free energy of the lithium metal electrode bulk, A interface is the Helmholtz free energy at the lithium metal / void interface, c L is the lattice concentration, R is the universal gas constant, T is the temperature, θ0 is the proportion of lithium atoms at the initial moment, V is the electrode volume, ζ is the non-conservative phase field order parameter, W is the barrier height, g(ζ) is the double well function, κ is the gradient energy coefficient, θ m is the proportion of lithium atoms.

4. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1 or 2, characterized in that: The concentration equation is as follows: ; Among them, c Li is the lithium atomic concentration, D T is the diffusion coefficient at temperature T, D ref is the reference diffusion coefficient, E is the diffusion energy barrier, k B is the Boltzmann constant, T ref is the reference temperature, μ Li is the chemical potential of lithium atoms and R is the universal gas constant.

5. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 4, characterized in that: The chemical potential μ of the lithium atom Li Calculate according to the following relationship: m Li =-RTln[θ0 / (1-θ0)]+RTln[θ m / (1-θ0)]-(Ω Li -Oh v )s h Among them, Ω Li is the molar volume of lithium atoms, σ h is the hydrostatic pressure, θ m is the proportion of lithium atoms, and θ0 is the proportion of lithium atoms at the initial moment.

6. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1 or 2, characterized in that: The electrochemical equation is as follows: ; Among them, σ SSE and are the conductivity and potential of the electrolyte, σ Li and are the conductivity and electrode potential of the lithium metal electrode, respectively, and f(ζ) is the interpolation function.

7. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1 or 2, characterized in that: The mechanical equation is as follows: ; Where C is the elastic stiffness tensor of the lithium metal electrode, C = C[h(ζ)E Li ,υ Li ], h(ζ) is the interpolation, E li is the Young's modulus of lithium metal, υ Li is the Poisson's ratio of lithium metal, ε el is the elastic strain, ε is the total strain, and ε cr is the creep strain, ε ch is the chemical strain, u is the displacement, c Li is the lithium atomic concentration, c ref is the reference lithium concentration, Ω Li is the molar volume of lithium atoms, Ω v is the molar volume of the vacancy, I is the second-order unit tensor, A is the pre-exponential factor, σ mises is the von Mises stress, σ ref is the reference stress, n is the power law exponent, Q is the creep activation energy, T ref is the reference temperature, T is the temperature, and R is the universal gas constant.

8. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1 or 2, characterized in that: The boundary conditions of the computational domain are as follows: ; Where n is the normal direction, L is the phase field migration coefficient, κ is the gradient energy coefficient, ζ is the phase field order parameter, and D T is the temperature-dependent diffusion coefficient, c Li is the lithium atomic concentration, R is the universal gas constant, T is the temperature, μ Li is the chemical potential of lithium atoms, i0 is the reference exchange current density, is the electrode potential, is the electrolyte potential, C is the elastic stiffness tensor, ε el is the elastic strain, p is the applied stack pressure, u is the displacement field, σ SSE is the electrolyte conductivity, f(ζ) is the interpolation function, σ Li is the conductivity of lithium metal and i is the applied current density.

9. A method for predicting void evolution in an all-solid-state lithium metal battery according to claim 1 or 2, characterized in that: The relationship between the cavity area is as follows: S=∫ Ω ζ<0.5 dxdy Where S is the area of ​​the void, ζ is the phase field order parameter, Ω is the computational domain, x is the horizontal coordinate, and y is the vertical coordinate.

10. A prediction system for void evolution in all-solid-state lithium metal batteries, characterized in that: The system includes an actuator, which is used to execute the prediction method for void evolution in an all-solid-state lithium metal battery as described in any one of claims 1-9.

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