Digital hybrid modeling method and system for roller kiln in ternary cathode material sintering process

Abstract

This invention discloses a digital hybrid modeling method and system for a roller kiln during the ternary cathode material sintering process. Based on the structural characteristics of the roller kiln sintering process and the inherent properties of the ternary cathode material, the temperature field region and the cellular reaction region, as well as the initial state of the temperature field region and the cellular reaction region, are determined. Based on the heat transfer mechanism of the temperature field during the sintering process, the thermal characteristics of the ternary cathode material are analyzed. Based on the energy conservation equation, a roller kiln temperature field model is established, and thermal radiation boundary conditions are designed. Based on the reaction characteristics of the cathode material, a cellular automaton model framework is established. Based on the chemical reaction state and material thermal characteristics of each cell, a formula is designed to describe the changing relationship between the cellular energy and the sagger position, thereby obtaining the cellular reaction boundary conditions. This invention provides a basis for clarifying the internal state of the roller kiln and improving product performance.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of ternary positive electrode materials, and in particular discloses a digital hybrid modeling method and system for a roller kiln in a ternary positive electrode material sintering process. Background Art

[0002] Lithium-ion batteries, with their high energy density, long cycle life, and excellent safety, have become one of the most widely used and promising batteries today. Cathode materials are one of the most important components in lithium-ion batteries. Ternary cathode materials, with their high specific capacity and high voltage platform, are considered the most promising cathode materials for electric vehicle power batteries.

[0003] In industrial production, the preparation of lithium-ion battery ternary positive electrode materials is mainly obtained by high-temperature solid-phase sintering, which includes a heating section, a constant temperature section, and a cooling section. Each temperature section is divided into multiple temperature zones, and the temperature and atmosphere between the temperature zones are coupled and affect each other. At the same time, the reactions occurring in each temperature zone are also different. The quality of the sintered product is closely related to the temperature, atmosphere, sintering time, etc. of each temperature zone. The sintering process is a complex chemical reaction process. After calcination for up to 22 hours and complex physical and chemical reaction changes, the required sintered product can be finally obtained. The material grains need to grow to a certain size to meet the technical indicators, and the temperature affects the reaction kinetics of material generation and grain growth, which in turn affects the microstructural characteristics of the material.

[0004] During the roller-hearth kiln sintering process of ternary cathode materials, multiple competing reactions occur, each consuming varying amounts of energy and material, and thus altering multiple physical fields to varying degrees. Conversely, the energy and material supply within the reaction environment directly determines the direction of these reactions and the resulting product. However, the real-time interaction between grain growth and the sintering environment during the ternary material sintering process has not yet been studied.

[0005] Therefore, accurately describing the sintering process of positive electrode materials by simultaneously considering the interaction between microscopic chemical reactions and macroscopic multi-physical fields is a problem that needs to be solved to achieve product quality improvement. Summary of the Invention

[0006] The present invention provides a digital hybrid modeling method and system for a roller kiln in the sintering process of a ternary positive electrode material, aiming to solve the technical problem that the internal temperature field is difficult to obtain due to the unclear coupling law between the microscopic reaction and the macroscopic environment during the sintering process of the ternary material.

[0007] One aspect of the present invention relates to a digital hybrid modeling method for a roller kiln in a ternary cathode material sintering process, comprising the following steps:

[0008] According to the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material, the temperature field area and the cellular reaction area, as well as the initial state of the temperature field area and the cellular reaction area, are determined;

[0009] According to the heat transfer mechanism of the temperature field during sintering, the thermal characteristics of the ternary cathode material are analyzed, the roller kiln temperature field model is established based on the energy conservation equation, and the thermal radiation boundary conditions are designed;

[0010] According to the reaction characteristics of the cathode material, a cellular automaton model framework is established. Based on the chemical reaction state and thermal properties of each cell, a formula is designed to describe the relationship between the cell energy and the position of the sagger, and the cellular reaction boundary conditions are obtained.

[0011] Based on the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions, a digital hybrid model of the sintering process combining micro and macro is established;

[0012] The temperature field of the roller kiln during the sintering process was simulated based on the hybrid model, and the temperature field simulation results of the ternary cathode material sintering process were obtained.

[0013] Furthermore, in the step of determining the temperature field region and the cellular reaction region, and the initial state of the temperature field region and the cellular reaction region, according to the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material,

[0014] According to the structural characteristics of the roller kiln, the sagger area is divided into the temperature field area and the cellular reaction area, and the temperature field model and the cellular reaction model are established in the temperature field area and the cellular reaction area respectively.

[0015] According to the preparation process and material properties of the ternary cathode material, the initial number of moles of reactants in each cell size of the sagger area can be obtained. and for:

[0016]

[0017] in, They are lithium hydroxide monohydrate LiOH·H2O and precursor Ni x Co y Mn (1-x-y) The relative molecular molar mass of (OH)2, n a ×n b is the number of independent cells into which the cellular reaction area is divided, r L is the ratio of the moles of the two reactants, M is the weight of the material in each sagger, n sagger is the number of saggers;

[0018] According to the structural characteristics and heat transfer characteristics of the roller kiln, the initial state of the temperature distribution in the sagger area is determined as follows:

[0019] T(x,z,0)=T0(x,z)

[0020] Among them, T(x,z,0) is the initial state of the temperature distribution in the sagger area, and T0(x,z) is the initial state of the temperature field area.

[0021] Furthermore, according to the heat transfer mechanism of the temperature field during the sintering process, the thermal characteristics of the ternary cathode material are analyzed, the roller kiln temperature field model is established based on the energy conservation equation, and the thermal radiation boundary conditions are designed.

[0022] According to the law of conservation of energy, the heat transfer mechanism of the temperature field in the sintering process is analyzed. Based on the characteristics of the ternary cathode material, the roller kiln temperature field model is established as follows:

[0023]

[0024] in, is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and v z are the gas velocities in the width and height directions of the kiln, respectively; k3 is the thermal conductivity of the porous medium; S T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln;

[0025] According to the heat transfer principle, the following boundary conditions are constructed:

[0026]

[0027] in, F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2),F a→s (x1,z),F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4 (z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces respectively; ∈ Pj Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j = 1, 2; P j is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, and P1 and P2 are the heating powers of the silicon carbon rods.

[0028] Furthermore, according to the reaction characteristics of the cathode material, a cellular automaton model framework is established, and according to the chemical reaction state and thermal properties of each cell, a formula is designed to describe the changing relationship between the cell energy and the sagger position, and in the step of obtaining the cell reaction boundary conditions,

[0029] The reaction rate α of the sample at any time t during the chemical reaction is defined as:

[0030]

[0031] Among them, m0 is the mass of the sample at the beginning of the reaction, m f is the mass of the sample at the end of the reaction, m t is the sample mass at the current moment;

[0032] The heating rate is defined as β = dT / dt. For a non-isothermal reaction system, the kinetic equation characterizing the reaction rate of the decomposition reaction can be described by the Arrhenius law:

[0033]

[0034] Where r is the reaction rate of the decomposition sample at the current temperature during the decomposition reaction, A is the pre-exponential factor, β is the heating rate, and E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, and f(α) is the kinetic mechanism function determined by the reaction mechanism;

[0035] Obtain the reaction amount ΔN of the decomposed sample at time t t for:

[0036]

[0037] Where ΔN t is the reaction amount of the decomposition sample at time t, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, f(α t ) represents the mechanism function, the independent variable of which is the reaction rate α at time t;

[0038] According to the definition of enthalpy change, calculate the energy consumed by the decomposition reaction at the current moment:

[0039]

[0040] Among them, ΔQ is the energy consumed by the decomposition reaction at the current moment, ΔN t is the reaction amount of the decomposition sample at time t, ΔH is the reaction enthalpy of the decomposition reaction at the current temperature, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, α t represents the reaction rate α at time t;

[0041] The temperature change of the microscopic boundary is calculated based on the calculated energy, and the microscopic boundary conditions are described as:

[0042]

[0043] in, Energy is needed for the reaction. is the output temperature of the microscopic reaction at the current moment, is the input temperature of the microscopic reaction at the previous moment; c represents the specific heat capacity of the material in the cell unit, and m represents the weight of the material in the cell unit;

[0044] According to the finite difference principle, the cell boundary is described as follows:

[0045]

[0046] in, Indicates that z = z i The rate of change of temperature at They represent the temperatures at time t at coordinate points (zi, xi+1), (zi, xi), and (zi+1, xi) respectively; Respectively represent the coordinate points (z i , x i +1)、(z i , x i )、(z i+1 , xi ), the temperature at time t-1;

[0047] The relationship between temperature gradient and position under different boundaries is described by the following formula:

[0048]

[0049] Among them, f(z i ,x i ) indicates that at the coordinate point (z i , x i ) is a function of the temperature change at the location; parameter set Θ = [a 11 ,a 12 ,a 13 ,a 21 ,a 22 ,a 23 ,a 31 ,a 32 ,a 33 ] is the parameter to be identified;

[0050] The cell boundary conditions during the sintering process of the ternary cathode material, that is, the relationship between temperature and position, can be described as:

[0051]

[0052] in, Respectively represent the rate of change of temperature at z = z1, z = z2, x = x1, x = x2; a 11 、a 12 、a 13 、a 21 、a 22 、a 23 、a 31 、a 32 、a 33 f(z i , x i ) function.

[0053] Furthermore, according to the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions, in the step of establishing a digital hybrid model of the sintering process combining micro and macro, the temperature field model in the established digital hybrid model combining micro and macro is:

[0054]

[0055] in, represents the rate of change of temperature at x = 0, is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and v z are the gas velocities in the width and height directions of the kiln, respectively; k3 is the thermal conductivity of the porous medium; S T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2),F a→s (x1,z),F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4 (z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T 4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces, respectively; P j is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a are used to represent the proportion of the received radiation to the total radiation; Ta represents the furnace wall temperature, P1 and P2 are the heating powers of the silicon carbon rods; f(z1,x), f(z2,x), f(z,x1), and f(z,x2) are functions of the changes in the cell boundary temperature at z=z1, z=z2, x=x1, and x=x2, respectively.

[0056] Another aspect of the present invention relates to a digital hybrid modeling system for a roller kiln in a ternary cathode material sintering process, comprising:

[0057] A determination module is used to determine the temperature field region and the cellular reaction region, as well as the initial states of the temperature field region and the cellular reaction region, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material;

[0058] The first establishment module is used to analyze the thermal characteristics of the ternary cathode material according to the heat transfer mechanism of the temperature field during the sintering process, establish the roller kiln temperature field model based on the energy conservation equation, and design the thermal radiation boundary conditions;

[0059] The second building module is used to establish a cellular automaton model framework based on the reaction characteristics of the positive electrode material. Based on the chemical reaction state and thermal properties of each cell, a formula is designed to describe the changing relationship between the cell energy and the sagger position, and obtain the cell reaction boundary conditions.

[0060] The third module is used to establish a digital hybrid model of the sintering process that combines micro and macro perspectives based on the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions;

[0061] The acquisition module is used to simulate the temperature field of the roller kiln in the sintering process based on the hybrid model and obtain the temperature field simulation results of the ternary positive electrode material sintering process.

[0062] Furthermore, in the determination module, the sagger area is divided into a temperature field area and a cellular reaction area according to the structural characteristics of the roller kiln, and a temperature field model and a cellular reaction model are established in the temperature field area and the cellular reaction area respectively;

[0063] According to the preparation process and material properties of the ternary cathode material, the initial number of moles of reactants in each cell size of the sagger area can be obtained. and for:

[0064]

[0065] in, They are lithium hydroxide monohydrate LiOH·H2O and precursor Ni x Co y Mn (1-x-y) The relative molecular molar mass of (OH)2, n a ×n b is the number of independent cells into which the cellular reaction area is divided, r L is the ratio of the moles of the two reactants, M is the weight of the material in each sagger, n sagger is the number of saggers;

[0066] According to the structural characteristics and heat transfer characteristics of the roller kiln, the initial state of the temperature distribution in the sagger area is determined as follows:

[0067] T(x,z,0)=T0(x,z)

[0068] Among them, T(x,z,0) is the initial state of the temperature distribution in the sagger area, and T0(x,z) is the initial state of the temperature field area.

[0069] Furthermore, in the first establishment module, the heat transfer mechanism of the temperature field in the sintering process is analyzed according to the law of conservation of energy, and based on the characteristics of the ternary cathode material, the roller kiln temperature field model established is specifically as follows:

[0070]

[0071] in, is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and v z are the gas velocities in the width and height directions of the kiln, respectively; k3 is the thermal conductivity of the porous medium; S T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln;

[0072] According to the heat transfer principle, the following boundary conditions are constructed:

[0073]

[0074] in, F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2),F a→s (x1,z),F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4 (z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T 4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces, respectively; Pj is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, and P1 and P2 are the heating powers of the silicon carbon rods.

[0075] Furthermore, in the second building module, the reaction rate α of the sample at any time t during the chemical reaction is defined as:

[0076]

[0077] Among them, m0 is the mass of the sample at the beginning of the reaction, m f is the mass of the sample at the end of the reaction, m t is the sample mass at the current moment;

[0078] The heating rate is defined as β = dT / dt. For a non-isothermal reaction system, the kinetic equation characterizing the reaction rate of the decomposition reaction can be described by the Arrhenius law:

[0079]

[0080] Where r is the reaction rate of the decomposition sample at the current temperature during the decomposition reaction, A is the pre-exponential factor, β is the heating rate, and E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, and f(α) is the kinetic mechanism function determined by the reaction mechanism;

[0081] Obtain the reaction amount ΔN of the decomposed sample at time t t for:

[0082]

[0083] Where ΔN t is the reaction amount of the decomposition sample at time t, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, f(α t ) represents the mechanism function, the independent variable of which is the reaction rate α at time t;

[0084] According to the definition of enthalpy change, calculate the energy consumed by the decomposition reaction at the current moment:

[0085]

[0086] Among them, ΔQ is the energy consumed by the decomposition reaction at the current moment, ΔN t is the reaction amount of the decomposition sample at time t, ΔH is the reaction enthalpy of the decomposition reaction at the current temperature, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, α t represents the reaction rate α at time t;

[0087] The temperature change of the microscopic boundary is calculated based on the calculated energy, and the microscopic boundary conditions are described as:

[0088]

[0089] in, Energy is needed for the reaction. is the output temperature of the microscopic reaction at the current moment, is the input temperature of the microscopic reaction at the previous moment; c represents the specific heat capacity of the material in the cell unit, and m represents the weight of the material in the cell unit;

[0090] According to the finite difference principle, the cell boundary is described as follows:

[0091]

[0092] in, Indicates that z = z i The rate of change of temperature at They represent the temperatures at time t at coordinate points (zi, xi+1), (zi, xi), and (zi+1, xi) respectively; Respectively represent the coordinate points (z i , x i +1)、(z i , x i )、(z i+1 , x i ), the temperature at time t-1;

[0093] The relationship between temperature gradient and position under different boundaries is described by the following formula:

[0094]

[0095] Among them, f(z i ,x i ) indicates that at the coordinate point (z i , x i ) is a function of the temperature change at the location; parameter set Θ = [a 11 ,a 12 ,a13 ,a 21 ,a 22 ,a 23 ,a 31 ,a 32 ,a 33 ] is the parameter to be identified;

[0096] The cell boundary conditions during the sintering process of the ternary cathode material, that is, the relationship between temperature and position, can be described as:

[0097]

[0098] Among them, a 11 、a 12 、a 13 、a 21 、a 22 、a 23 、a 31 、a 32 、a 33 f(z i , x i ) function.

[0099] Furthermore, in the third building module, the temperature field model in the digital hybrid model combining micro and macro is established as follows:

[0100]

[0101] in, is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and v z are the gas velocities in the width and height directions of the kiln, respectively; k3 is the thermal conductivity of the porous medium; S T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2)F a→s (x1,z)F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4(z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T 4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces respectively; ∈ Pj Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j = 1, 2; P j is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a are used to represent the proportion of the received radiation to the total radiation; Ta represents the furnace wall temperature, P1 and P2 are the heating powers of the silicon carbon rods; f(z1,x), f(z2,x), f(z,x1), and f(z,x2) are functions of the changes in the cell boundary temperature at z=z1, z=z2, x=x1, and x=x2, respectively.

[0102] The beneficial effects achieved by the present invention are:

[0103] The present invention provides a digital hybrid modeling method and system for a roller kiln in a ternary positive electrode material sintering process. The method comprises the following steps: determining the temperature field region and the cellular reaction region, as well as the initial state of the temperature field region and the cellular reaction region, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary positive electrode material; analyzing the thermal characteristics of the ternary positive electrode material according to the heat transfer mechanism of the temperature field in the sintering process, establishing a roller kiln temperature field model based on the energy conservation equation, and designing thermal radiation boundary conditions; establishing a cellular automaton model framework according to the reaction characteristics of the positive electrode material, and designing a formula to describe the changing relationship between the cellular energy and the sagger position according to the chemical reaction state and the thermal characteristics of the material of each cell, thereby obtaining the cellular reaction boundary conditions; establishing a digital hybrid model of the sintering process combining microscopic and macroscopic aspects, based on the coefficients in the relevant property identification model of the ternary positive electrode material and in combination with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions; and performing temperature field simulation on the roller kiln in the sintering process according to the hybrid model to obtain the temperature field simulation results of the ternary positive electrode material sintering process. The digital hybrid modeling method and system for a roller kiln in the ternary positive electrode material sintering process provided by the present invention respectively model the temperature field and microscopic reaction of the ternary positive electrode material sintering process, and innovatively connect the macroscopic and microscopic models of two different scales through the reaction environment and energy transfer, thereby realizing real-time interaction between the material grain growth and the sintering environment; and providing a basis for clarifying the internal state of the roller kiln and improving the performance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] Figure 1 A schematic flow chart of an embodiment of a digital hybrid modeling method for a roller kiln in a ternary cathode material sintering process provided by the present invention;

[0105] Figure 2 Schematic diagram of a roller kiln in the digital hybrid modeling method of a roller kiln for the ternary cathode material sintering process provided by the present invention;

[0106] Figure 3 A graph showing the energy variation of a cell in the roller kiln decomposition reaction during the sintering process of the ternary cathode material provided by the present invention;

[0107] Figure 4 A curve diagram of the temperature variation of the center of the sagger in the roller kiln under a fixed heating power during the sintering process of the ternary cathode material provided by the present invention;

[0108] Figure 5 This is the final temperature field distribution diagram of the roller kiln decomposition reaction stage in the ternary cathode material sintering process provided by the present invention;

[0109] Figure 6 This is a functional block diagram of an embodiment of a digital hybrid modeling system for a roller kiln in the ternary cathode material sintering process provided by the present invention.

[0110] Description of Figure Numbers:

[0111] 10. Determination module; 20. First establishment module; 30. Second establishment module; 40. Third establishment module; 50. Acquisition module. DETAILED DESCRIPTION

[0112] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0113] This embodiment discloses a digital hybrid modeling method for roller kilns during the ternary cathode material sintering process. This method separately models the temperature field and microscopic reactions during the ternary cathode material sintering process. The two models are then linked through the reaction environment and energy transfer. This method enables real-time interaction between material grain growth and the sintering environment, helping to clarify the internal state of the sintering process.

[0114] This example takes the actual process flow of preparing ternary cathode materials used in a lithium-ion battery cathode material production enterprise in China as an example to simulate the main raw materials: lithium hydroxide monohydrate LiOH·H2O and precursor nickel cobalt manganese oxide (Ni 0.83 Co 0.11 Mn 0.06 (OH)2) decomposition reaction stage during the sintering preparation process.

[0115] In order to achieve the above objectives, the temperature field area and the cellular reaction area and their initial states are determined according to the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material; according to the heat transfer mechanism of the temperature field in the sintering process, the thermal characteristics of the ternary cathode material are analyzed, and a roller kiln temperature field model is established based on the energy conservation equation, and the thermal radiation boundary conditions are designed; according to the reaction characteristics of the cathode material, a cellular automaton model framework is established, and according to the chemical reaction state and material thermal characteristics of each cell, a formula is designed to describe the changing relationship between the cell energy and the sagger position, and the cellular reaction boundary conditions are obtained; according to the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions, a digital hybrid model of the sintering process combining micro and macro is established; based on the hybrid model, the temperature field of the roller kiln in the sintering process is simulated, and the temperature field simulation results of the ternary cathode material sintering process are obtained.

[0116] like Figures 1 to 5 As shown, an embodiment of the present invention provides a digital hybrid modeling method of a roller kiln for a ternary cathode material sintering process, comprising the following steps:

[0117] Step S100: determining the temperature field region and the cellular reaction region, as well as the initial states of the temperature field region and the cellular reaction region, according to the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material.

[0118] According to the structural characteristics of the roller kiln, the sagger area is divided into modeling areas, and the temperature field model and cellular reaction model are established in this area respectively. The initial states are determined as follows:

[0119] according to Figure 2 , the area x1≤x≤x2,z1≤z≤z2 in the roller kiln area is divided into the sagger temperature field area and the sagger cell reaction area. The sagger area is divided into 2 layers and 4 rows with a total of 8 saggers. The weight of the material in each sagger is Mkg. The cell reaction area is divided into a length and width of n a ×n b In the process of preparing ternary cathode materials, there are initial reactants of lithium hydroxide monohydrate LiOH·H2O and precursor Ni0.83Co0.11Mn0.06(OH)2, and the ratio of reactants is r L :1. According to the relative molecular mass of the reactants The initial number of moles of reactant present in each cell size can be obtained for:

[0120]

[0121] In formula (1), is the initial molar number of lithium hydroxide monohydrate; is the initial molar number of the precursor; They are lithium hydroxide monohydrate LiOH·H2O and precursor Ni x Co y Mn (1-x-y) The relative molecular molar mass of (OH)2, n a is the number of cell region lengths; n b is the number of cell area widths; n a ×n b is the number of independent cells into which the cellular reaction area is divided, r L is the ratio of the moles of the two reactants, M is the weight of the material in each sagger, n sagger is the number of saggers.

[0122] In this embodiment, n a =200,n b =100, r L =1.05, M=4.

[0123] According to the structural characteristics and heat transfer characteristics of the roller kiln, the initial state of the temperature distribution in the sagger area is:

[0124] T(x,z,0)=T0(x,z) (2)

[0125] In formula (2), T(x,z,0) is the initial state of the temperature distribution in the sagger area, and T0(x,z) is the initial state of the temperature field area, that is, the initial temperature. This initial temperature is a function related to the position of the x-axis and the z-axis.

[0126] Step S200: Analyze the thermal characteristics of the ternary cathode material according to the heat transfer mechanism of the temperature field during the sintering process, establish a roller kiln temperature field model based on the energy conservation equation, and design thermal radiation boundary conditions.

[0127] According to the law of conservation of energy, the heat transfer mechanism of the temperature field in the sintering process is analyzed, and based on the characteristics of the ternary cathode material, such as Figure 3 As shown in the figure, the established roller kiln temperature field model is specifically as follows:

[0128]

[0129] In formula (3), is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas (i.e., oxygen) in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid (material powder) in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and vz are the speeds of the gas in the width and height directions of the kiln, respectively; k1, k2 and k3 are the thermal conductivity coefficients of the gas in the furnace, the solid in the sagger area and the porous medium, respectively. T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln.

[0130] It is known that the volume ratio of the pores of the powdered material in the sagger to the sagger area is γ (i.e., porosity). Then the density and specific heat capacity of the porous medium in the sagger area are ρ3c3=(1-γ)ρ2c2+γρ1c1, and the thermal conductivity coefficient k3 of the porous medium satisfies the relationship k3=(1-γ)k2+γk1.

[0131] According to the heat transfer principle, the following boundary conditions are constructed:

[0132]

[0133] In formula (4), F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2),F a→s (x1,z),F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4 (z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T 4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces, respectively; P j is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, and P1 and P2 are the heating powers of the silicon carbon rods.

[0134] Step S300: Establish a cellular automaton model framework based on the reaction characteristics of the positive electrode material, and design a formula to describe the relationship between the cell energy and the sagger position based on the chemical reaction state and material thermal properties of each cell to obtain the cell reaction boundary conditions.

[0135] Perform thermodynamic analysis on each stage of the reaction, establish a cellular automaton model framework, obtain the current reaction quantity, and design a formula to describe the relationship between the cell energy and the position of the sagger based on the chemical reaction state and material thermal properties of each cell. The steps to obtain the cellular reaction boundary conditions are as follows:

[0136] The reaction rate α of the sample at any time t during the chemical reaction is defined as:

[0137]

[0138] In formula (5), m0 is the mass of the sample at the beginning of the reaction, m f is the mass of the sample at the end of the reaction, m t The reaction rate α is between 0 and 1 and is usually used to indicate the degree of thermal decomposition reaction in heterogeneous systems.

[0139] The heating rate is defined as β = dT / dt. For a non-isothermal reaction system, the kinetic equation characterizing the reaction rate of the decomposition reaction can be described by the Arrhenius law:

[0140]

[0141] In formula (6), r is the reaction rate of the decomposition sample at the current temperature during the decomposition reaction, A is the pre-exponential factor, E is the activation energy, R is the molar gas constant, which is taken as 8.314472 J / K, T is the thermodynamic temperature, and f(α) is the kinetic mechanism function determined by the reaction mechanism, which is taken according to expert experience.

[0142] The reaction amount ΔN of the decomposed sample at time t can be obtained t for:

[0143]

[0144] In formula (7), ΔN t is the reaction amount of the decomposition sample at time t, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, f(α t ) represents the mechanism function, the independent variable of which is the reaction rate α at time t.

[0145] According to the definition of enthalpy change, the energy consumed by the decomposition reaction at the current moment can be calculated, such as Figure 4 shown.

[0146]

[0147] In formula (8), ΔQ is the energy consumed by the decomposition reaction at the current moment, ΔN t is the reaction amount of the decomposition sample at time t, ΔH is the reaction enthalpy of the decomposition reaction at the current temperature, N t-1 is the amount of decomposed sample remaining at the previous moment; A is the pre-exponential factor, β is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, α t represents the reaction rate α at time t.

[0148] Since the obtained cell energy is discrete, it is necessary to make the discrete boundaries continuous. First, the temperature change of the microscopic boundary is calculated based on the calculated energy. The microscopic boundary conditions can be described as:

[0149]

[0150] In formula (9), Energy is needed for the reaction. is the output temperature of the microscopic reaction at the current moment, is the input temperature of the microscopic reaction at the previous moment; c represents the specific heat capacity of the material in the cell unit, and m represents the weight of the material in the cell unit.

[0151] According to the finite difference principle, the cell boundary is described as follows:

[0152]

[0153] In formula (10), Indicates that z = z i The rate of change of temperature at They represent the temperatures at time t at coordinate points (zi, xi+1), (zi, xi), and (zi+1, xi) respectively; Respectively represent the coordinate points (z i , x i +1)、(z i , x i )、(z i+1 , x i ), the temperature at time t-1.

[0154] The cell boundary is a series of discrete points, while the temperature field boundary is a continuous function. Therefore, it is necessary to fit the calculated series of discrete cell boundaries to make them into a continuous function. Taking the boundary as an example, it is necessary to describe the relationship between the temperature gradient and position under different boundaries. The following formula is used to describe it:

[0155]

[0156] In formula (11), f(z i ,x i ) indicates that at the coordinate point (z i , x i ) is a function of the temperature change at the location; parameter set Θ = [a 11 ,a 12 ,a 13 ,a 21 ,a 22 ,a 23 ,a 31 ,a 32 ,a 33 ] are the parameters to be identified.

[0157] The cell boundary conditions during the sintering process of the ternary cathode material, that is, the relationship between temperature and position, can be described as:

[0158]

[0159] In formula (12), a 11 、a 12 、a 13 、a 21 、a 22 、a 23 、a 31 、a 32 、a 33 f(z i , x i ) function.

[0160] Step S400: Based on the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions, a digital hybrid model of the sintering process combining micro and macro is established.

[0161] The physical parameters in the temperature field model are determined according to the material properties, and the thermodynamic analysis of each stage of the reaction is carried out to solve the three thermodynamic factors of each stage. The temperature field model in the digital hybrid model combining micro and macro is established by combining the heat transfer boundary conditions of the temperature field with the cellular reaction boundary conditions.

[0162]

[0163] In formula (13), is the temperature distribution in the sagger area, t is time; x represents the width direction of the kiln, z represents the height direction of the kiln; ρ1 and c1 are the density and specific heat capacity of the gas in the furnace, ρ2 and c2 are the density and specific heat capacity of the solid in the sagger area, ρ3 and c3 are the density and specific heat capacity of the porous medium, v x and v z are the gas velocities in the width and height directions of the kiln, respectively; k3 is the thermal conductivity of the porous medium; S T It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; F Pj (x1,z),F Pj (x2,z) represents the angular coefficient of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; F a→s (x,z1),F a→s (x,z2),F a→s (x1,z),F a→s (x2,z) represents the angular coefficient of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; T 4 (z1,x,t),T 4 (z2,x,t),T 4 (z,x1,t),T 4 (z, x2, t) represents the fourth power of the temperature of the sagger area at z = z1, z = z2, x = x1, and x = x2 respectively; represents the fourth power of the furnace wall temperature; k3 is the thermal conductivity of the porous medium; A1 and A2 are finite surfaces at z = z1, z2 on the upper and lower surfaces and x = x1, x2 on the left and right surfaces respectively; ∈ Pj Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j = 1, 2; P j is the heating power of the silicon carbon rod, j = 1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; F a→b Represents the angular coefficient of a to b; ∈ s 、 ∈ a are used to represent the proportion of the received radiation to the total radiation; Ta represents the furnace wall temperature, P1 and P2 are the heating powers of the silicon carbon rods; f(z1,x), f(z2,x), f(z,x1), and f(z,x2) are functions of the changes in the cell boundary temperature at z=z1, z=z2, x=x1, and x=x2, respectively.

[0164] Step S500: simulate the temperature field of the roller kiln during the sintering process according to the hybrid model to obtain the temperature field simulation results of the ternary cathode material sintering process.

[0165] Based on the established digital hybrid model of micro- and macro-coupling, the following Figure 5 The steps for simulating the temperature field of the roller kiln during the sintering process include:

[0166] The roller kiln sagger area of ​​the sintering process is determined as the modeling area, the cell size is divided, the amount of reactant in each cell is calculated, and the initial state of the temperature field is determined according to the current state of the roller kiln;

[0167] Calculate the temperature at the next moment based on the current initial temperature state, input the temperature distribution into the cellular model, calculate the change in the number of moles of each substance in the cell and the change in the energy consumed by the reaction, convert the obtained energy change into a temperature gradient change, and obtain the cellular boundary conditions through the fitting method;

[0168] Combined with the cellular boundary conditions, the temperature field boundary is modified, and the new roller kiln temperature distribution is calculated based on the updated boundary. The obtained temperature field is input into the cellular model to obtain the cellular boundary at the next moment. This cycle is repeated until the particle reaction is completed.

[0169] Through the boundary condition energy and environment exchange between the temperature field model and the cellular model, the temperature field distribution and the amount of ternary material particles in each step of the reaction are continuously changed, and the sintering process temperature distribution containing microscopic reaction information is obtained.

[0170] like Figure 6 As shown, Figure 6The functional block diagram of an embodiment of the digital hybrid modeling system of the roller kiln for the ternary positive electrode material sintering process provided by the present invention. In this embodiment, the digital hybrid modeling system of the roller kiln for the ternary positive electrode material sintering process provided by the present invention includes a determination module 10, a first establishment module 20, a second establishment module 30, a third establishment module 40 and an acquisition module 50, wherein the determination module 10 is used to determine the temperature field area and the cellular reaction area, as well as the initial state of the temperature field area and the cellular reaction area according to the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary positive electrode material; the first establishment module 20 is used to analyze the thermal characteristics of the ternary positive electrode material according to the heat transfer mechanism of the temperature field of the sintering process, based on the energy conservation equation A roller kiln temperature field model is established, and thermal radiation boundary conditions are designed; a second establishment module 30 is used to establish a cellular automaton model framework according to the reaction characteristics of the positive electrode material, and according to the chemical reaction state and material thermal characteristics of each cell, a formula is designed to describe the changing relationship between the cell energy and the sagger position, and obtain the cellular reaction boundary conditions; a third establishment module 40 is used to identify the coefficients in the model according to the relevant properties of the ternary positive electrode material, combine the temperature field heat transfer boundary conditions with the cellular reaction boundary conditions, and establish a digital hybrid model of the sintering process that combines micro and macro; an acquisition module 50 is used to simulate the temperature field of the roller kiln in the sintering process according to the hybrid model, and obtain the temperature field simulation results of the ternary positive electrode material sintering process.

[0171] Compared with the prior art, the digital hybrid modeling method and system for a roller kiln in the ternary positive electrode material sintering process provided in this embodiment determine the temperature field area and the cellular reaction area, as well as the initial state of the temperature field area and the cellular reaction area, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary positive electrode material; analyze the thermal characteristics of the ternary positive electrode material based on the heat transfer mechanism of the temperature field during the sintering process, establish a roller kiln temperature field model based on the energy conservation equation, and design thermal radiation boundary conditions; establish a cellular automaton model framework based on the reaction characteristics of the positive electrode material, and design a formula to describe the changing relationship between the cell energy and the sagger position based on the chemical reaction state and material thermal characteristics of each cell to obtain the cellular reaction boundary conditions; establish a digital hybrid model of the sintering process combining micro and macro based on the coefficients in the relevant property identification model of the ternary positive electrode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions; simulate the temperature field of the roller kiln in the sintering process based on the hybrid model to obtain the temperature field simulation results of the ternary positive electrode material sintering process. The digital hybrid modeling method and system for the roller kiln of the ternary positive electrode material sintering process provided in this embodiment, by separately modeling the temperature field and microscopic reaction of the ternary positive electrode material sintering process, innovatively connects the macroscopic and microscopic models of two different scales through the reaction environment and energy transfer, thereby realizing real-time interaction between the material grain growth and the sintering environment; and provides a basis for clarifying the internal state of the roller kiln and improving the performance of the product.

[0172] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A digital hybrid modeling method for roller kiln in the sintering process of ternary cathode materials, characterized in that: The following steps are involved: Determining the temperature field region and the cellular reaction region, as well as the initial states of the temperature field region and the cellular reaction region, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material; According to the heat transfer mechanism of the temperature field during sintering, the thermal characteristics of the ternary cathode material are analyzed, the roller kiln temperature field model is established based on the energy conservation equation, and the thermal radiation boundary conditions are designed; According to the reaction characteristics of the cathode material, a cellular automaton model framework is established. Based on the chemical reaction state and thermal properties of each cell, a formula is designed to describe the relationship between the cell energy and the position of the sagger, and the cellular reaction boundary conditions are obtained. Based on the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions, a digital hybrid model of the sintering process combining micro and macro is established; The temperature field of the roller kiln in the sintering process is simulated according to the hybrid model to obtain the temperature field simulation results of the ternary cathode material sintering process; The temperature field model in the digital hybrid model combining micro and macro is: in, represents the rate of change of temperature at x=0, is the temperature distribution in the sagger area, t For time; x Represents the width of the kiln, z Represents the height direction of the kiln; and are the density and specific heat capacity of the gas in the furnace, and are the density and specific heat capacity of the solid in the sagger area, and are the density and specific heat capacity of the porous medium, and are the gas velocities in the width and height directions of the kiln, is the thermal conductivity of the porous medium; It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; 、 、 、 Respectively represent the angular coefficients of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; 、 、 、 They represent the angular coefficients of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; 、 、 、 They represent the fourth power of the sagger area temperature at z=z1, z=z2, x=x1, and x=x2 respectively; Indicates the fourth power of the furnace wall temperature; Thermal conductivity of porous media; 、 are finite surfaces at z=z1,z2 on the upper and lower surfaces and x=x1,x2 on the left and right surfaces respectively; is the heating power of the silicon carbon rod, j=1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; represents the angular coefficient of a to b; They are used to indicate the proportion of received radiation to total radiation; 、 、 、 They represent the functions of the cell boundary temperature changes at z=z1, z=z2, x=x1, and x=x2 respectively.

2. The digital hybrid modeling method for roller kiln in the ternary cathode material sintering process according to claim 1, characterized in that: In the step of determining the temperature field region and the cellular reaction region, and the initial states of the temperature field region and the cellular reaction region, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material, According to the structural characteristics of the roller kiln, the sagger area is divided into a temperature field area and a cellular reaction area, and a temperature field model and a cellular reaction model are established in the temperature field area and the cellular reaction area respectively; According to the preparation process and material properties of the ternary cathode material, the initial number of moles of reactants in each cell size of the sagger area can be obtained. and for: in, is the initial molar number of lithium hydroxide monohydrate; is the initial molar number of the precursor; 、 Lithium hydroxide monohydrate LiOH · H 2 O and precursors Ni x Co y Mn (1-x-y) ( OH )2 relative molecular molar mass, is the number of independent cells into which the cellular reaction area is divided, is the number of cell region lengths; is the number of cell area widths; r L is the ratio of the moles of the two reactants, M The weight of the material in each sagger, n sagger is the number of saggers; According to the structural characteristics and heat transfer characteristics of the roller kiln, the initial state of the temperature distribution in the sagger area is determined as follows: in, is the initial state of temperature distribution in the sagger area, is the initial state of the temperature field region.

3. The digital hybrid modeling method for roller kiln in the ternary cathode material sintering process according to claim 2, characterized in that: In the step of analyzing the thermal characteristics of the ternary cathode material according to the heat transfer mechanism of the temperature field during the sintering process, establishing a roller kiln temperature field model based on the energy conservation equation, and designing the thermal radiation boundary conditions, According to the law of conservation of energy, the heat transfer mechanism of the temperature field in the sintering process is analyzed. Based on the characteristics of the ternary cathode material, the roller kiln temperature field model is established as follows: in, is the temperature distribution in the sagger area, t For time; x Represents the width of the kiln, z Represents the height direction of the kiln; and are the density and specific heat capacity of the gas in the furnace, and are the density and specific heat capacity of the solid in the sagger area, and are the density and specific heat capacity of the porous medium, and are the gas velocities in the width and height directions of the kiln, is the thermal conductivity of the porous medium; It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; According to the heat transfer principle, the following boundary conditions are constructed: in, 、 、 、 Respectively represent the angular coefficients of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; 、 、 、 They represent the angular coefficients of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; 、 、 、 They represent the fourth power of the sagger area temperature at z=z1, z=z2, x=x1, and x=x2 respectively; Indicates the fourth power of the furnace wall temperature; Thermal conductivity of porous media; 、 are finite surfaces at z=z1,z2 on the upper and lower surfaces and x=x1,x2 on the left and right surfaces respectively; Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j=1, 2; is the heating power of the silicon carbon rod, j=1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; represents the angular coefficient of a to b; They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, and P1 and P2 are the heating powers of the silicon carbon rods.

4. The digital hybrid modeling method for roller kiln in the ternary cathode material sintering process according to claim 3, characterized in that: In the step of establishing a cellular automaton model framework based on the reaction characteristics of the positive electrode material, and designing a formula to describe the changing relationship between the cell energy and the sagger position based on the chemical reaction state and material thermal characteristics of each cell, and obtaining the cell reaction boundary conditions, Define the sample at any time during the chemical reaction t Time-to-time response rate for: in, m 0 is the sample mass at the beginning of the reaction, m f is the mass of the sample at the end of the reaction, m t is the sample mass at the current moment; The heating rate is defined as For a non-isothermal reaction system, the kinetic equation characterizing the reaction rate of the decomposition reaction can be described by the Arrhenius law: Among them, r is the reaction rate of the decomposition sample at the current temperature during the decomposition reaction, A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, is the kinetic mechanism function determined by the reaction mechanism; get t The reaction volume of the sample decomposed at each moment for: in, is the reaction amount of the decomposition sample at time t, The amount of decomposition sample remaining at the previous moment; A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, taken as 8.314472 J / K; T is the thermodynamic temperature, Represents the mechanism function, the independent variable of which is the reaction rate at time t ; According to the definition of enthalpy change, calculate the energy consumed by the decomposition reaction at the current moment: in, The energy consumed by the decomposition reaction at the current moment, is the reaction amount of the decomposition sample at time t, is the reaction enthalpy of the decomposition reaction at the current temperature, The amount of decomposition sample remaining at the previous moment; A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, taken as 8.314472 J / K; T is the thermodynamic temperature, represents the reaction rate at time t ; The temperature change of the microscopic boundary is calculated based on the calculated energy, and the microscopic boundary conditions are described as: in, Energy is needed for the reaction. is the output temperature of the microscopic reaction at the current moment, is the input temperature of the microscopic reaction at the previous moment; c represents the specific heat capacity of the material in the cell, and m represents the weight of the material in the cell; According to the finite difference principle, the cell boundary is described as follows: in, Indicates that z=z i The rate of change of temperature at 、 、 Respectively represent the coordinate points (z i , x i+1 )、(z i , x i )、(z i+1 , x i ), the temperature at time t; 、 、 Respectively represent the coordinate points (z i , x i +1)、(z i , x i )、(z i+1 , x i ), the temperature at time t-1; The relationship between temperature gradient and position under different boundaries is described by the following formula: in, Indicates that at the coordinate point (z i , x i ) is a function of the temperature change at ; parameter set is the parameter to be identified; The cell boundary conditions during the sintering process of the ternary cathode material, that is, the relationship between temperature and position, can be described as: in, 、 、 、 They represent the rate of change of temperature at z=z1, z=z2, x=x1, and x=x2 respectively; 、 、 、 、 、 、 、 、 for Parameters in the function.

5. A digital hybrid modeling system for roller kiln in the sintering process of ternary cathode materials, characterized by: include: A determination module (10) is used to determine the temperature field region and the cellular reaction region, as well as the initial states of the temperature field region and the cellular reaction region, based on the structural characteristics of the roller kiln sintering process and the inherent characteristics of the ternary cathode material; The first establishment module (20) is used to analyze the thermal characteristics of the ternary cathode material according to the heat transfer mechanism of the temperature field during the sintering process, establish a roller kiln temperature field model based on the energy conservation equation, and design thermal radiation boundary conditions; The second establishment module (30) is used to establish a cellular automaton model framework according to the reaction characteristics of the positive electrode material, and to design a formula to describe the relationship between the change of the cell energy and the sagger position according to the chemical reaction state and material thermal characteristics of each cell, so as to obtain the cell reaction boundary conditions; The third establishment module (40) is used to establish a digital hybrid model of the sintering process combining micro and macro, based on the coefficients in the relevant property identification model of the ternary cathode material, combined with the temperature field heat transfer boundary conditions and the cellular reaction boundary conditions; An acquisition module (50) is used to simulate the temperature field of the roller kiln during the sintering process according to the hybrid model, and obtain the simulation results of the temperature field of the ternary cathode material sintering process; Among them, in the third establishment module (40), the temperature field model in the digital hybrid model combining micro and macro is established as follows: in, is the temperature distribution in the sagger area, t For time; x Represents the width of the kiln, z Represents the height direction of the kiln; and are the density and specific heat capacity of the gas in the furnace, and are the density and specific heat capacity of the solid in the sagger area, and are the density and specific heat capacity of the porous medium, and are the gas velocities in the width and height directions of the kiln, is the thermal conductivity of the porous medium; It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; 、 、 、 Respectively represent the angular coefficients of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; 、 、 、 They represent the angular coefficients of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; 、 、 、 They represent the fourth power of the sagger area temperature at z=z1, z=z2, x=x1, and x=x2 respectively; Indicates the fourth power of the furnace wall temperature; Thermal conductivity of porous media; 、 are finite surfaces at z=z1,z2 on the upper and lower surfaces and x=x1,x2 on the left and right surfaces respectively; Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j=1, 2; is the heating power of the silicon carbon rod, j=1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; represents the angular coefficient of a to b; They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, P1 and P2 are the heating powers of the silicon carbon rod respectively; 、 、 、 They represent the functions of the cell boundary temperature changes at z=z1, z=z2, x=x1, and x=x2 respectively.

6. The digital hybrid modeling system for roller kiln in the ternary cathode material sintering process according to claim 5, characterized in that: In the determination module (10), the sagger area is divided into a temperature field area and a cellular reaction area according to the structural characteristics of the roller kiln, and a temperature field model and a cellular reaction model are established in the temperature field area and the cellular reaction area respectively; According to the preparation process and material properties of the ternary cathode material, the initial number of moles of reactants in each cell size of the sagger area can be obtained. and for: in, is the initial molar number of lithium hydroxide monohydrate; is the initial molar number of the precursor; 、 Lithium hydroxide monohydrate LiOH · H 2 O and precursors Ni x Co y Mn (1-x-y) ( OH )2 relative molecular molar mass, is the number of independent cells into which the cellular reaction area is divided, is the number of cell region lengths; is the number of cell area widths; r L is the ratio of the moles of the two reactants, M The weight of the material in each sagger, n sagger is the number of saggers; According to the structural characteristics and heat transfer characteristics of the roller kiln, the initial state of the temperature distribution in the sagger area is determined as follows: in, is the initial state of temperature distribution in the sagger area, is the initial state of the temperature field region.

7. The digital hybrid modeling system for roller kiln in the ternary cathode material sintering process according to claim 6, characterized in that: In the first establishment module (20), the heat transfer mechanism of the temperature field in the sintering process is analyzed according to the law of conservation of energy, and based on the characteristics of the ternary cathode material, the roller kiln temperature field model established is specifically as follows: in, is the temperature distribution in the sagger area, t For time; x Represents the width of the kiln, z Represents the height direction of the kiln; and are the density and specific heat capacity of the gas in the furnace, and are the density and specific heat capacity of the solid in the sagger area, and are the density and specific heat capacity of the porous medium, and are the gas velocities in the width and height directions of the kiln, is the thermal conductivity of the porous medium; It is the internal heat source released during the sintering process in the sagger area and can be temporarily ignored in the temperature field of the roller kiln; According to the heat transfer principle, the following boundary conditions are constructed: in, 、 、 、 Respectively represent the angular coefficients of the silicon carbon rod to the sagger at z=z1, z=z2, x=x1, x=x2, j=1, 2; 、 、 、 They represent the angular coefficients of the furnace wall to the sagger at z=z1, z=z2, x=x1, and x=x2 respectively; 、 、 、 They represent the fourth power of the sagger area temperature at z=z1, z=z2, x=x1, and x=x2 respectively; Indicates the fourth power of the furnace wall temperature; Thermal conductivity of porous media; 、 are finite surfaces at z=z1,z2 on the upper and lower surfaces and x=x1,x2 on the left and right surfaces respectively; Indicates the proportion of radiation received by the upper and lower silicon carbon rods to the total radiation, j=1, 2; is the heating power of the silicon carbon rod, j=1, 2; x1, x2, z1, z2 are the boundaries of the sagger area; represents the angular coefficient of a to b; They are used to represent the proportion of received radiation to the total radiation; Ta represents the furnace wall temperature, and P1 and P2 are the heating powers of the silicon carbon rods.

8. The digital hybrid modeling system for roller kiln in the ternary cathode material sintering process according to claim 7, characterized in that: In the second establishment module (30), it is defined that the sample is t Time-to-time response rate for: in, m 0 is the sample mass at the beginning of the reaction, m f is the mass of the sample at the end of the reaction, m t is the sample mass at the current moment; The heating rate is defined as For a non-isothermal reaction system, the kinetic equation characterizing the reaction rate of the decomposition reaction can be described by the Arrhenius law: Among them, r is the reaction rate of the decomposition sample at the current temperature during the decomposition reaction, A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, which is 8.314472 J / K; T is the thermodynamic temperature, is the kinetic mechanism function determined by the reaction mechanism; get t The reaction volume of the sample decomposed at each moment for: in, is the reaction amount of the decomposition sample at time t, The amount of decomposition sample remaining at the previous moment; A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, taken as 8.314472 J / K; T is the thermodynamic temperature, To represent the mechanism function, the independent variable of the mechanism function is the reaction rate at time t ; According to the definition of enthalpy change, calculate the energy consumed by the decomposition reaction at the current moment: in, The energy consumed by the decomposition reaction at the current moment, is the reaction amount of the decomposition sample at time t, is the reaction enthalpy of the decomposition reaction at the current temperature, The amount of decomposition sample remaining at the previous moment; A is the pre-exponential factor, is the heating rate, E is the activation energy; R is the molar gas constant, taken as 8.314472 J / K; T is the thermodynamic temperature, represents the reaction rate at time t ; The temperature change of the microscopic boundary is calculated based on the calculated energy, and the microscopic boundary conditions are described as: in, Energy is needed for the reaction. is the output temperature of the microscopic reaction at the current moment, is the input temperature of the microscopic reaction at the previous moment; c represents the specific heat capacity of the material in the cell, and m represents the weight of the material in the cell; According to the finite difference principle, the cell boundary is described as follows: in, Indicates that z=z i The rate of change of temperature at 、 、 They represent the temperatures at time t at coordinate points (zi, xi+1), (zi, xi), and (zi+1, xi) respectively; 、 、 Respectively represent the coordinate points (z i , x i +1)、(z i , x i )、(z i+1 , x i ), the temperature at time t-1; The relationship between temperature gradient and position under different boundaries is described by the following formula: in, Indicates that at the coordinate point (z i , x i ) is a function of the temperature change at ; parameter set is the parameter to be identified; The cell boundary conditions during the sintering process of the ternary cathode material, that is, the relationship between temperature and position, can be described as: in, 、 、 、 、 、 、 、 、 for Parameters in the function.

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