A system and method for preparing an encapsulant film for a photovoltaic module

Abstract

The application discloses a kind of adhesive film preparation systems and methods for photovoltaic module, it is related to photovoltaic material technical field, system includes extrusion unit, co-extrusion die, casting cooling unit and control unit, co-extrusion die lip mouth outlet and casting cooling unit outlet are respectively set by near-infrared hyperspectral camera and dielectric spectrum sensor and are monitored component, obtains the concentration distribution and surface precipitation of each layer auxiliary agent of three-layer composite film piece, control unit calculates auxiliary agent cross-layer migration rate according to two monitoring data, closed loop adjusts die partition temperature and extrusion pressure, and according to precipitation, adjust casting roll heating array power and stationed electrode voltage, induce the micron level rough texture formed on adhesive film surface, improve adhesive film interlayer bonding force and module laminating qualified rate.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic materials technology, specifically to a system and method for preparing encapsulant films for photovoltaic modules. Background Technology

[0002] With the large-scale production of N-type photovoltaic cells, polyolefin elastomer (POE) films and EVA-POE-EVA three-layer co-extruded composite films (hereinafter referred to as EPE films) are widely used due to their superior water resistance and resistance to potential-induced degradation compared to traditional EVA films. The outer EVA layer of the EPE film contains crosslinking agents, co-crosslinking agents, and silane coupling agents. Because of the significant difference in polarity and melt viscosity between EVA and POE, these outer-layer additives tend to migrate to the core POE layer during extrusion casting, leading to uneven crosslinking of the POE layer and decreased interlayer bonding strength. This can easily cause delamination during module lamination. For pure POE films, due to the poor compatibility between POE resin and polar additives, these additives tend to precipitate onto the film surface during extrusion casting, resulting in a decrease in the surface friction coefficient. This can easily cause slippage of the solar cells during module lamination. To address the issue of microcracks, current industrial encapsulant film production equipment typically includes multiple extruders, co-extrusion dies, smooth casting rollers, and traction winding devices. During production, process parameters such as die temperature and screw speed are set according to a fixed formula without real-time feedback adjustments. Product quality mainly relies on offline sampling using xylene extraction to detect the degree of crosslinking, which has a long detection cycle and makes it difficult to achieve real-time control during production. In this existing solution, the co-extrusion die lip outlet is not equipped with an online monitoring device, and the casting rollers do not have the function of dynamically adjusting according to the amount of additives released. This makes it difficult to detect and eliminate the impact of raw material batch differences and environmental temperature and humidity fluctuations on product quality in a timely manner. Furthermore, offline detection methods cannot meet the requirements for real-time closed-loop control at the source of production. Therefore, we propose a photovoltaic module encapsulant film preparation system and method. Summary of the Invention

[0003] The purpose of this invention is to provide a system and method for preparing encapsulant film for photovoltaic modules.

[0004] The technical problem to be solved by this invention is: how to achieve online, non-destructive, and real-time monitoring of the cross-layer migration state and surface precipitation state of additives in the continuous preparation process of photovoltaic encapsulant film by extrusion casting, and to perform closed-loop control of extrusion process parameters based on the monitoring results, so as to suppress the delamination problem caused by the migration of additives between EPE film layers from the production source, and at the same time solve the module lamination slippage problem caused by the precipitation of additives on the surface of pure POE film, thereby improving the interlayer bonding force of the encapsulant film and the lamination qualification rate of photovoltaic modules;

[0005] To address the aforementioned technical problems, this invention provides a photovoltaic module encapsulant film preparation system, comprising an extrusion unit, a co-extrusion die, a casting and cooling unit, and a control unit. The extrusion unit includes three extruders for plasticizing and melting the raw materials of the first EVA layer, POE layer, and second EVA layer, respectively. The co-extrusion die is equipped with three independent melt channels, each connected to one of the three extruders. The three melt channels converge inside the co-extrusion die and are extruded through a lip to form a three-layer composite film with the first EVA layer, POE layer, and second EVA layer sequentially stacked along the thickness direction. A first monitoring component is disposed at the lip exit of the co-extrusion die along the width direction of the film. The first monitoring component includes a near-infrared hyperspectral camera and a dielectric spectrum sensor, used to collect the spectral signals and dielectric response signals corresponding to the concentration distribution of each additive layer when the film is first formed. The casting and cooling unit includes… The casting roller has a heating array, a stationary electrode, and a cooling water channel arranged axially and circumferentially inside the roller body for cooling and shaping the film. A second monitoring component is set at the outlet of the casting cooling unit to collect the spectral and dielectric response signals corresponding to the migration state of the additives and the amount of surface precipitation after the film is cooled and shaped. The control unit calculates the estimated value of the POE layer additive concentration at the co-extrusion die lip outlet and the casting cooling unit outlet based on the signals collected by the two-stage monitoring components, and calculates the cross-layer migration rate of the additives based on the difference between the two and the residence time of the film between the two monitoring points. Then, it adjusts the local temperature of the corresponding zone of the co-extrusion die and the extrusion pressure of the corresponding extruder. The control unit also adjusts the heating array power and stationary electrode voltage of the corresponding area of ​​the casting roller based on the estimated value of surface additive precipitation to induce the formation of a micron-level rough texture on the film surface.

[0006] The present invention provides a method for preparing a photovoltaic module encapsulant film, comprising the steps of plasticizing and melting three layers of raw materials respectively, extruding them together through a co-extrusion die to form a three-layer composite film, performing two online scanning monitoring at the co-extrusion die outlet and the casting cooling unit outlet, calculating the cross-layer migration rate of additives based on the two-level monitoring data and adjusting the die zone temperature and extrusion pressure in a closed loop, adjusting the casting roller heating array power and stationary electrode voltage in a closed loop based on the amount of surface additive precipitation, and traction trimming and winding to obtain the finished encapsulant film.

[0007] Compared with the prior art, the beneficial effects of the present invention by adopting the above technical solution are as follows:

[0008] 1. This invention achieves online, non-destructive monitoring of the concentration distribution and cross-layer migration state of additives in multilayer melts by setting a composite monitoring component consisting of a near-infrared hyperspectral camera and a dielectric spectrum sensor at two locations: the lip outlet of the co-extrusion die and the outlet of the casting cooling unit. This transforms quality judgment from offline destructive sampling inspection to real-time online control during the production process.

[0009] 2. This invention dynamically adjusts the temperature and extrusion pressure of the co-extrusion die section by using closed-loop feedback of the cross-layer migration rate of additives, thereby creating a dynamic adjustment effect at the POE layer interface, inhibiting cross-layer migration of additives from the production source, improving the interlayer bonding force of EPE film, and reducing the delamination defect rate.

[0010] 3. This invention uses the coordinated dynamic adjustment of the casting roller heating array and the stationary electrode to actively induce the formation of a micron-level rough texture on the surface of the film based on the feedback of the amount of additive precipitation. This increases the friction coefficient of the film surface without changing the main POE formula, thus avoiding the problems of cell slippage and microcracks during the lamination process of photovoltaic modules. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the hardware architecture of the complete EPE film production system in an embodiment of the present invention;

[0012] Figure 2 This is a schematic diagram of the closed-loop control process for adjuvant migration in an embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of the collaborative control process of the adhesive film surface texture in an embodiment of the present invention. Detailed Implementation

[0014] The following is in conjunction with the appendix Figure 1-3 The specific embodiments of the present invention will be further described below. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0015] Furthermore, 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.

[0016] I. System Overall Architecture:

[0017] The photovoltaic module encapsulant film preparation system provided in this embodiment mainly includes an extrusion unit, a co-extrusion die, a casting and cooling unit, a control unit, and a digital twin platform;

[0018] The extrusion unit includes a first extruder, a second extruder, and a third extruder, which are used to plasticize and melt the first EVA layer material, the POE layer material, and the second EVA layer material, respectively. The screw speeds of the first extruder, the second extruder, and the third extruder are independently controlled by their respective frequency converters and receive adjustment commands from the control unit.

[0019] The co-extrusion die is equipped with a first melt flow channel, a second melt flow channel, and a third melt flow channel that are respectively connected to the first extruder, the second extruder, and the third extruder. The three melt flow channels gradually narrow and merge in the confluence area inside the co-extrusion die, and finally are extruded through a unified lip to form a three-layer composite film with a first EVA layer, a POE layer, and a second EVA layer stacked sequentially along the thickness direction. The co-extrusion die is divided into multiple temperature zones along the width direction of the film, and each temperature zone is equipped with an independent heating band to achieve local temperature regulation in the zone.

[0020] A high-temperature resistant sapphire window is installed on the outer side of the lip of the co-extrusion die, and a cooling air curtain nozzle is configured on the outer side of the window to isolate the thermal radiation effect of the high-temperature melt on the optical components. A first monitoring component is set at the lip exit of the co-extrusion die along the width direction of the film. The first monitoring component includes a first near-infrared hyperspectral camera and a first dielectric spectrum sensor. The first near-infrared hyperspectral camera scans the width direction of the film point by point through the sapphire window to collect hyperspectral data reflecting the initial concentration distribution of each layer of additives. The first dielectric spectrum sensor detects the dielectric response characteristics of each point of the film in a non-contact manner. The signals collected by the two are fused and processed in the control unit as the first-level online monitoring data.

[0021] The core component of the casting cooling unit is an adaptive micro-nano textured casting roll. Electromagnetic induction micro-heating arrays are uniformly arranged along the axial and circumferential directions inside the casting roll body for localized heating of the roll surface. Several independently controlled electrostatic stationary electrodes are set on the surface of the roll body to apply localized electrostatic adsorption force to the melt. A cooling water channel is set inside the roll body for overall or regional cooling and shaping of the roll surface. After the three-layer composite film is cooled and shaped by the casting roll, it enters the outlet of the casting cooling unit. A second monitoring component is set along the width direction of the film at this point. The second monitoring component includes a second near-infrared hyperspectral camera and a second dielectric spectrum sensor to collect the spectral signal and dielectric response signal corresponding to the final auxiliary agent migration state and surface precipitation amount of the film after casting cooling, as the second-level online monitoring data.

[0022] The control unit is electrically connected to the first monitoring component, the second monitoring component, the first extruder, the second extruder, the third extruder, the heating belts of each zone of the co-extrusion die, and the heating array and stationary electrodes of the casting roller. The control unit receives data from the two-level monitoring components, runs the online inversion algorithm of additive concentration, migration rate calculation, temperature-rheological gradient closed-loop control algorithm and adaptive micro-nano texture control algorithm, and sends control commands to each execution component.

[0023] The digital twin platform is connected to the control unit and is used for visualizing data from the entire production process, storing historical data, and periodically iteratively training the concentration inversion model.

[0024] II. Online Inversion Method for Additive Concentration and Migration Rate Calculation:

[0025] The first and second monitoring components simultaneously acquire hyperspectral data and dielectric spectral response data from multiple sampling points along the width direction of the membrane. The control unit performs black-and-white correction, multivariate scattering correction, and smoothing filtering noise reduction on the acquired hyperspectral data to obtain preprocessed spectral features. The dielectric spectral data is normalized, and the preprocessed spectral features are concatenated with the normalized dielectric spectral features to form a fused feature vector, which is used as the input to the concentration inversion model.

[0026] The concentration inversion model can be expressed as:

[0027] ;

[0028] In the formula, Indicates the first The estimated concentration of POE layer additives obtained from the inversion of each monitoring point For the regression intercept term, For the fusion feature vector of the th The regression coefficients corresponding to each component are obtained by regression analysis using offline calibration data. For the fused feature vector, the first Each feature component To reduce the total dimension of the fused feature vectors, the model can be implemented using partial least squares regression or a convolutional neural network. Its parameters are trained using the true concentration values ​​obtained by periodic calibration using an offline xylene extraction method, and are incrementally updated by adding newly collected calibration data to the training set.

[0029] The control unit calculates the cross-layer migration rate of the additives based on the estimated concentrations of the POE layer additives at the co-extrusion die lip outlet (first-level monitoring point) and the POE layer additives concentration at the casting cooling unit outlet (second-level monitoring point), combined with the residence time of the film between the two monitoring points. The calculation formula is as follows:

[0030] ;

[0031] In the formula, This indicates the rate at which the additive migrates across layers from the EVA layer to the POE layer. This represents the estimated concentration of POE layer additives at the exit lip of the co-extrusion die. This represents the estimated concentration of POE layer additives at the outlet of the casting cooling unit. This indicates the dwell time of the diaphragm between two monitoring points, which can be calculated from the production line speed and the distance between the two monitoring points.

[0032] III. Temperature-Rheological Gradient Closed-Loop Control Method:

[0033] The control unit controls the cross-layer migration rate of the adjuvant. Compared to the pre-set upper limit of the migration rate target Compare and calculate the deviation:

[0034] ;

[0035] Based on deviation The proportional-integral-derivative (PI-DE) control algorithm is used to calculate the local temperature adjustment required for the corresponding module head partition of the POE layer. The control law is expressed as follows:

[0036] ;

[0037] In the formula, express Temperature adjustment amount for the corresponding mold head zone of the POE layer at any given time. , , These are the proportional, integral, and derivative control coefficients, which are determined during on-site commissioning. for Migration rate deviation at time step Let be the integral variable, representing the time from the initial moment to . The process of accumulating historical deviations at any given moment;

[0038] The control unit, based on the temperature adjustment amount and the correlation between melt viscosity and temperature, determines whether the melt viscosity adjustment amount at the POE layer interface has reached the preset viscosity threshold. If it has not reached the threshold, the adjustment range is further increased. The relationship between melt viscosity and temperature is approximately expressed as follows:

[0039] ;

[0040] In the formula, Indicates temperature The viscosity of the lower POE layer melt. Let be the viscosity constant of the reference state. It is the activation energy for melt flow. This is the universal gas constant. The absolute temperature of the POE layer melt is used as the control unit to convert the temperature adjustment amount into the power adjustment signal of the corresponding die head heating zone and the extrusion pressure adjustment signal of the corresponding extruder. These signals are then sent to each execution component. The migration rate feedback value is reacquired in the next sampling cycle, and the above calculation process is repeated to form a continuous closed-loop regulation until the additive migration rate converges to within the target range.

[0041] IV. Adaptive Micro / Nano Texture Casting Roller Control Method

[0042] The control unit inverts the signal collected by the second monitoring component to obtain an estimated value of the amount of additives precipitated on the film surface. Compare it with the preset target precipitation threshold. Compare and calculate the deviation:

[0043] ;

[0044] when deviation When the precipitation amount is greater than zero, i.e., exceeds the target threshold, the control unit calculates the local heating power adjustment of the electromagnetic induction micro-heating array in the corresponding area of ​​the casting roller surface according to the proportional control law:

[0045] ;

[0046] In the formula, This indicates the adjustment amount of the heating power of the local electromagnetic induction micro-heating array on the casting roller. This is the proportional control coefficient. This is an estimated value for the amount of surface additives precipitated as currently monitored. To achieve the preset target precipitation threshold, the control unit increases the temperature of the roller surface in that area to change the local melt cooling rate. Simultaneously, it adjusts the applied voltage of the electrostatic stationary electrode in that area to change the local electrostatic stationary force on the roller surface. This, in conjunction with the heating power adjustment, controls the microscopic shrinkage and accumulation behavior of the melt on the roller surface, inducing the formation of a micron-level rough texture, i.e., a locking agent microporous structure. This structure is used to physically lock the precipitated additive molecules and increase the friction coefficient of the adhesive film surface. After the local texture on the roller surface is formed, the area is cooled and shaped by the cooling water circuit, allowing the adhesive film surface to solidify and form the locking agent microporous structure. In the next production cycle, the surface precipitation data is collected again to determine the actual locking effect of the locking agent micropores. If the precipitation still exceeds the target range, the above adjustment process is repeated until it converges to within the target range.

[0047] V. Overall Preparation Method:

[0048] The raw materials for the first EVA layer, POE layer, and second EVA layer are respectively added to their respective extruders for plasticizing and melting. The three melt streams are then conveyed to the corresponding melt channels inside the co-extrusion die, where they converge and are extruded through the lip to form a three-layer composite film with the first EVA layer, POE layer, and second EVA layer stacked sequentially along the thickness direction. The three-layer composite film is first scanned and monitored online using a first monitoring component to obtain the spectral and dielectric response signals corresponding to the initial concentration distribution of each additive layer. The estimated concentration of the POE layer additive at the lip exit of the co-extrusion die is calculated. The three-layer composite film then enters the casting and cooling unit, where it is cooled and shaped by an adaptive micro / nano textured casting roller. The three-layer composite film is then scanned and monitored online a second time using a second monitoring component to obtain the final additive concentration. The spectral and dielectric response signals corresponding to the agent migration state and surface additive precipitation amount are used to calculate the estimated values ​​of POE layer additive concentration and surface additive precipitation amount at the outlet of the casting cooling unit. Based on the difference between the two estimated values ​​of POE layer additive concentration and the residence time of the film between the two monitoring points, the cross-layer migration rate of the additive is calculated. Based on this, the local temperature of the corresponding zone of the co-extrusion die head and the extrusion pressure of the corresponding extruder are adjusted in a closed loop. Based on the estimated value of surface additive precipitation amount, the heating array power and the stationary electrode voltage of the corresponding area of ​​the casting roller are adjusted in a closed loop to induce the formation of a micron-level rough texture on the film surface. The three-layer composite film is pulled, trimmed and wound by the traction device to obtain the finished photovoltaic film. The monitoring data of the whole process is uploaded to the digital twin platform in real time for storage, visualization and periodic iterative training of the concentration inversion model.

[0049] VI. Other implementation methods:

[0050] In other embodiments, the means of monitoring the migration and concentration of additives can be to use online ultrasonic detection instead of near-infrared hyperspectral imaging. That is, ultrasonic transmitting and receiving probes are arranged at the outlet of the co-extrusion die head and the outlet of the casting cooling unit. By monitoring the changes in the ultrasonic propagation speed and attenuation coefficient in the melt or film, the additive concentration distribution and interlayer migration state can be indirectly reflected, so as to achieve non-contact, online monitoring.

[0051] In other embodiments, the surface texture of the casting roll may not be formed by coordinating the electromagnetic induction heating array and the electrostatic stationary electrode. Instead, a micro-nano texture with a fixed pattern may be pre-processed on the surface of the casting roll. Combined with the feedback signal of the amount of additive precipitation monitored online, the production line running speed and the overall cooling temperature of the casting roll are adjusted to achieve a similar anti-slip effect.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art should understand that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be covered within the protection scope of the present invention.

[0053] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A photovoltaic module encapsulant film preparation system, characterized in that, It includes an extrusion unit, a co-extrusion die, a casting and cooling unit, and a control unit; The extrusion unit includes a first extruder, a second extruder, and a third extruder, which are used to plasticize and melt the first EVA layer material, the POE layer material, and the second EVA layer material, respectively. The screw speeds of the first extruder, the second extruder, and the third extruder are independently controlled by their respective frequency converters. The co-extrusion die is provided with three independent melt channels that are respectively connected to the first extruder, the second extruder and the third extruder. The three melt channels converge inside the co-extrusion die and are extruded through the lip to form a three-layer composite film with a first EVA layer, a POE layer and a second EVA layer stacked sequentially along the thickness direction. A first monitoring component is provided at the lip exit of the co-extrusion die along the width direction of the film. The first monitoring component includes a first near-infrared hyperspectral camera and a first dielectric spectrum sensor, which are used to collect the spectral signals and dielectric response signals corresponding to the concentration distribution of each layer of additives when the three-layer composite film is just formed. The casting cooling unit includes a casting roller, and the inside of the casting roller is provided with a heating array, stationary electrodes and cooling water channels arranged along the axial and circumferential directions. The casting roller is used to cool and shape the three-layer composite film extruded through the co-extrusion die. A second monitoring component is provided at the outlet of the casting cooling unit. The second monitoring component includes a second near-infrared hyperspectral camera and a second dielectric spectrum sensor, which are used to collect the spectral signals and dielectric response signals corresponding to the migration state of the additives and the amount of surface additives precipitated on the three-layer composite film after cooling and shaping. The control unit is electrically connected to the first monitoring component, the second monitoring component, the first extruder, the second extruder, the third extruder, the co-extrusion die, and the casting roll. Based on signals collected by the first and second monitoring components, the control unit calculates estimated POE layer additive concentrations at the lip outlet of the co-extrusion die and at the outlet of the casting cooling unit. Based on the difference between the two estimated POE layer additive concentrations and the residence time of the three-layer composite film between the lip outlet of the co-extrusion die and the outlet of the casting cooling unit, the control unit calculates the additive cross-layer migration rate. Based on the additive cross-layer migration rate, the control unit adjusts the local temperature of the corresponding zone of the co-extrusion die and the extrusion pressure of the corresponding extruder. Based on signals collected by the second monitoring component, the control unit calculates an estimated amount of surface additive precipitation. Based on the correlation between the additive cross-layer migration rate and the estimated amount of surface additive precipitation, the control unit determines whether surface precipitation is caused by insufficient cross-layer migration. Accordingly, it coordinately adjusts the heating array power and stationary electrode voltage of the corresponding area of ​​the casting roll to achieve coordinated control of cross-layer migration suppression and surface micron-level rough texture induction.

2. The photovoltaic module encapsulant film preparation system according to claim 1, characterized in that: The co-extrusion die is divided into multiple temperature zones along the width of the film. Each temperature zone is equipped with an independent heating belt. The control unit calculates the local temperature adjustment amount of the temperature zone corresponding to the POE layer using a proportional-integral-derivative control algorithm based on the deviation between the cross-layer migration rate of the additive and the preset upper limit of the migration rate. The control unit then controls the power of the corresponding heating belt and the extrusion pressure of the corresponding extruder based on the local temperature adjustment amount.

3. The photovoltaic module encapsulant film preparation system according to claim 1, characterized in that: A sapphire window is installed on the outer side of the lip of the co-extrusion die, and a cooling air curtain nozzle is disposed on the outer side of the sapphire window. The first near-infrared hyperspectral camera scans and images the film width direction through the sapphire window.

4. The photovoltaic module encapsulant film preparation system according to claim 1, characterized in that: The heating array is an electromagnetic induction micro-heating array, which is arranged in sections along the axial and circumferential directions of the casting roll body. The stationing electrode is an electrostatic stationing electrode, which is independently set on the surface of the casting roll body and is used to apply local electrostatic adsorption force to the melt.

5. The photovoltaic module encapsulant film preparation system according to claim 4, characterized in that: The control unit calculates the heating power adjustment of the electromagnetic induction micro-heating array in the corresponding area of ​​the casting roller according to the proportional control law based on the deviation between the estimated value of the surface additive precipitation and the preset target precipitation threshold, and simultaneously adjusts the applied voltage of the electrostatic stationary electrode in the corresponding area.

6. The photovoltaic module encapsulant film preparation system according to claim 5, characterized in that: It also includes a digital twin platform connected to the control unit, which is used to store the data collected by the first monitoring component and the second monitoring component, and to iteratively update the parameters of the adjuvant concentration inversion model based on the periodically acquired offline calibration data.

7. A method for preparing an encapsulant film for photovoltaic modules, characterized in that, include: The raw materials for the first EVA layer, the POE layer, and the second EVA layer are respectively added to the corresponding extruders for plasticizing and melting. Three melts are transported to the corresponding melt channels inside the co-extrusion die, where they converge and are extruded through the lip to form a three-layer composite film. The three-layer composite film consists of a first EVA layer, a POE layer, and a second EVA layer stacked sequentially along the thickness direction. The three-layer composite film is monitored online for the first time by a first monitoring component set at the lip outlet of the co-extrusion die, and the spectral signal and dielectric response signal corresponding to the initial concentration distribution of each layer of additives in the three-layer composite film are obtained. The estimated value of the POE layer additive concentration at the lip outlet of the co-extrusion die is calculated based on the spectral signal and the dielectric response signal. The three-layer composite film enters the casting and cooling unit, where the casting rollers cool and shape the three-layer composite film. The three-layer composite film after cooling and shaping is monitored online for the second time by a second monitoring component set at the outlet of the casting cooling unit. The spectral signal and dielectric response signal corresponding to the final auxiliary migration state and surface auxiliary precipitation amount of the three-layer composite film are obtained. The estimated value of POE layer auxiliary concentration and estimated value of surface auxiliary precipitation amount at the outlet of the casting cooling unit are calculated based on the spectral signal and the dielectric response signal. The additive cross-layer migration rate is calculated based on the difference between the estimated POE layer additive concentration at the co-extrusion die lip outlet and the estimated POE layer additive concentration at the casting cooling unit outlet, and the residence time of the three-layer composite film between the co-extrusion die lip outlet and the casting cooling unit outlet. Based on the deviation between the cross-layer migration rate of the additive and the preset upper limit of the migration rate target, the local temperature of the corresponding zone of the co-extrusion die and the extrusion pressure of the corresponding extruder are adjusted. Based on the deviation between the estimated amount of surface additive precipitation and the preset target precipitation threshold, the heating array power and stationary electrode voltage of the corresponding area of ​​the casting roller are adjusted to induce the formation of a micron-level rough texture on the surface of the three-layer composite film during the cooling and shaping process. The three-layer composite film is traction, trimming, and winding to obtain the finished adhesive film.

8. The method for preparing a photovoltaic module encapsulant film according to claim 7, characterized in that: The steps for adjusting the local temperature of the corresponding zone of the co-extrusion die and the extrusion pressure of the corresponding extruder include: using a proportional-integral-derivative control algorithm to calculate the temperature adjustment amount of the corresponding die zone of the POE layer based on the deviation; determining whether the melt viscosity adjustment amount of the POE layer interface reaches the preset viscosity threshold based on the temperature adjustment amount combined with the correspondence between melt viscosity and temperature; converting the temperature adjustment amount into a power adjustment signal for the heating belt of the corresponding die zone and an extrusion pressure adjustment signal for the corresponding extruder and sending them for execution.

9. A method for preparing a photovoltaic module encapsulant film according to claim 7, characterized in that: The steps of adjusting the heating array power and the stationary electrode voltage of the corresponding area of ​​the casting roller include: calculating the heating power adjustment amount of the heating array of the corresponding area of ​​the casting roller according to the proportional control law, synchronously adjusting the applied voltage of the stationary electrode of the corresponding area of ​​the casting roller, and cooling and shaping the area through the cooling water circuit after the texture of the corresponding area is formed.

10. A method for preparing a photovoltaic module encapsulant film according to claim 7, characterized in that, Also includes: The data collected by the first monitoring component and the second monitoring component are uploaded to the digital twin platform for storage, and the periodically acquired offline calibration data are added to the training set to iteratively update the parameters of the adjuvant concentration inversion model.

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