Composite water-blocking conductive front film suitable for flexible CIGS solar cell and preparation method of composite water-blocking conductive front film

Abstract

The invention relates to the technical field of flexible CIGS (Copper Indium Gallium Selenide) solar cells, in particular to a composite water-blocking conductive front film suitable for a flexible CIGS solar cell and a preparation method of the composite water-blocking conductive front film. Specifically, the composite water-blocking conductive front film comprises a substrate, an inorganic water-blocking layer is deposited on the upper surface of the substrate, a copper net is fixed on the lower surface of the substrate through an adhesive film layer, and the inorganic water-blocking layer, the substrate, the adhesive film layer and the copper net are of an integrated composite structure from top to bottom. According to the composite water-blocking conductive front film, the inorganic water-blocking layer and the adhesive film layer are formed on the surface of the substrate in a double-sided alternate processing mode, so that the risk that the water-blocking layer is damaged due to the fact that a water-blocking film is adopted for secondary processing at present is reduced, and when the composite water-blocking conductive front film is used for preparing a solar cell, the use amount of EVA is reduced, and the production cost is reduced. The overall thickness is reduced, the overall weight is reduced, and meanwhile the overall structural stability, bendability, flexibility and photoelectric performance can be improved.

Description

Technical Field

[0001] This invention relates to the field of flexible CIGS solar cell technology, and in particular to a composite water-blocking and conductive front film suitable for flexible CIGS solar cells and its preparation method. Background Technology

[0002] Flexible CIGS solar cells have broad application prospects in distributed photovoltaics and emerging niche markets due to their advantages such as lightweight, high flexibility, and high photoelectric conversion efficiency. However, the environmental adaptability and long-term reliability of flexible CIGS photovoltaic modules are highly dependent on their encapsulation structure. Traditional encapsulation processes typically employ multi-layer film lamination structures, such as sequentially layering EVA (ethylene-vinyl acetate copolymer) film, ETFE (ethylene-tetrafluoroethylene copolymer) protective film, and water-blocking film, to achieve functions such as water vapor resistance, oxidation resistance, corrosion resistance, and mechanical protection.

[0003] Although existing encapsulation technologies are relatively mature, as flexible CIGS modules develop towards lighter weight, higher flexibility, and higher reliability, the limitations of traditional multilayer film encapsulation structures are becoming increasingly apparent, mainly in the following aspects: First, there are issues of process complexity and cost: Traditional packaging requires the layering of multiple functional films (such as water-blocking film, adhesive layer, protective layer, etc.), which is complicated and the production yield is greatly affected by the lamination process parameters (temperature, pressure, time), increasing manufacturing costs and process control difficulties. Second, the contradiction between thickness and flexibility: the stacking of multiple films increases the overall thickness of the component, which not only reduces bending performance (such as limited radius of curvature) but also increases weight, making it difficult to meet the requirements of lightweight application scenarios; Third, loss of optical performance and power generation efficiency: The difference in interface reflection and transmittance of each layer of film material will reduce the effective utilization rate of incident light. The multilayer structure further leads to light loss, affecting the photoelectric conversion efficiency of the battery and indirectly increasing the unit power generation cost. Interface adhesion and long-term reliability risks: The multilayer film structure introduces more interface bonding areas. Under environmental stress such as damp heat and cold cycles, it is easy to cause delamination, debonding and other problems due to the mismatch of material expansion coefficients, thereby reducing the weather resistance and service life of the module.

[0004] The existing CIGS battery module encapsulation scheme consists of ETFE film, EVA, water-blocking film, EVA, ICI film, CIGS battery, EVA and backsheet from top to bottom. This structure has the problem of excessive EVA usage, which not only increases the overall weight but also reduces the light transmittance.

[0005] Therefore, there is an urgent need for a new structural design that can integrate water-blocking, electrical conductivity, light transmission, and mechanical protection functions while reducing the number of membrane layers, so as to improve the overall performance and market competitiveness of flexible CIGS modules. Summary of the Invention

[0006] This invention addresses the aforementioned technical problems by proposing a composite water-blocking and conductive front film suitable for flexible CIGS solar cells and its preparation method. Through material optimization and structural innovation, the preparation process is simplified, the preparation difficulty is reduced, the overall weight is decreased, and the thickness of the multi-film structure is reduced, thereby improving flexibility and reducing light loss, thus improving photoelectric conversion efficiency. Furthermore, it can improve the yield rate of product preparation and reduce the number of defective products in the manufacturing process. Achieve efficient, thin, and reliable packaging of flexible CIGS batteries.

[0007] Specifically, the present invention adopts the following technical solution: A composite water-blocking and conductive front film suitable for flexible CIGS solar cells, the composite water-blocking and conductive front film includes a substrate, an inorganic water-blocking layer deposited on the upper surface of the substrate, and a copper mesh fixed on the lower surface of the substrate by an adhesive film layer. The inorganic water-blocking layer, the substrate, the adhesive film layer and the copper mesh are an integral composite structure from top to bottom.

[0008] In the above structure, the present invention uses a copper mesh instead of traditional silver paste grid lines, specifically by printing, etching, electroplating and other methods to prepare the copper mesh circuit.

[0009] Furthermore, the substrate material is polyethylene terephthalate, polyamide, polyethylene naphthalate, or polyimide.

[0010] Furthermore, the material of the adhesive film layer is polyethylene, polypropylene, propylene oxide, thermoplastic polyolefin, polyurethane, or thermoplastic polyurethane elastomer.

[0011] Furthermore, the inorganic water-blocking layer is an inorganic oxide, specifically one of silicon oxide, fluoride, aluminum oxide, titanium dioxide, silicon nitride, silicon carbide, and zinc sulfide.

[0012] Furthermore, the inorganic water-blocking layer is prepared on the substrate by plasma-enhanced atomic layer deposition.

[0013] Furthermore, a camouflage layer is laminated onto the composite water-blocking and conductive front film. The camouflage is mainly prepared by methods such as solution deposition, thermal transfer, and laser printing.

[0014] Furthermore, the material of the copper mesh is a Cu-M alloy, wherein M is at least one metal selected from Zn, Al, Sn, and Ni, and the content of M is 1-2%.

[0015] This invention employs an adhesive film layer such as TPO for bonding, thereby increasing mechanical reliability and effectively preventing interface delamination between the copper mesh circuit and the CIGS battery, ensuring stability during long-term use. Furthermore, it utilizes thermoplastic resin for easy secondary processing, allowing connection to the copper mesh via secondary heating.

[0016] Specifically, using thermoplastic polyolefin (TPO) as an adhesive, TPO can form a high-strength bond with copper mesh circuits and CIGS batteries at relatively low heating temperatures (TPO's melting point is 120-130℃), resulting in lower energy efficiency compared to traditional silver paste. TPO adhesives possess excellent flexibility, UV resistance, and weather resistance, effectively improving module durability. Using TPO spraying or coating technology achieves a uniform adhesive layer, reducing interfacial voids and enhancing the overall structural strength of the flexible module. Similarly, other thermoplastic resin adhesives offer similar advantages.

[0017] The composite water-blocking and conductive front film of the present invention, using thermoplastic resin bonding and other technologies, can improve the problem of excessive film layer usage in traditional methods, reduce the thickness and weight of flexible CIGS photovoltaic cells, improve the curvature and photovoltaic conversion efficiency of photovoltaic modules, and enhance the long-term stability and reliability of flexible CIGS photovoltaic cells.

[0018] This invention creatively deposits an inorganic water-blocking layer on the upper surface of a substrate using plasma-enhanced atomic layer deposition (PEALD), while a copper mesh is fixed to the lower surface of the substrate via an adhesive film layer. This method employs a double-sided alternating processing approach. First, an adhesive layer is coated and formed on the substrate, and then an inorganic water-blocking layer is formed on the other side of the substrate. This processing method effectively avoids the problem of water-blocking layer damage and failure that can easily occur when purchasing existing water-blocking films.

[0019] The specific advantages of this process are as follows: Currently available commercially available base films with water-blocking layers (such as PET films) inevitably suffer damage to the surface water-blocking layer during lamination, leading to its failure. Specifically, during the preparation of the TPO layer, temperature differences can cause uneven stress on both sides of the water-blocking layer, resulting in cracking, damage, and other risks that cause the water-blocking layer to fail. The double-sided alternating processing technology of this invention allows for coating after TPO, avoiding the heating problem of the inorganic water-blocking layer during TPO processing. This prevents stress concentration during the current preparation process from causing cracking of the inorganic water-blocking layer.

[0020] A method for preparing a composite water-blocking and conductive front film suitable for flexible CIGS solar cells includes the following steps: First, an adhesive film layer is applied to one side of the substrate using a casting coating machine, and then an inorganic water-blocking layer is deposited using plasma-enhanced atomic layer deposition. Then, a copper mesh is prepared by etching or electroplating, and the copper mesh is combined with the side of the substrate coated with an adhesive film layer to obtain a composite water-blocking and conductive front film.

[0021] The specific steps of the above method are as follows: Step 1: An adhesive film layer is coated on one side of the substrate using a double-sided alternating processing method, and an inorganic water-blocking layer is deposited on the other side. Specifically, the substrate is passed through the roll-to-roll equipment chamber of a casting coating machine at a temperature of 160-200℃ to coat one side of the substrate with an adhesive film layer. Then, the substrate is passed through the plasma-enhanced atomic layer deposition equipment chamber at a temperature of 20-120℃ to deposit an inorganic water-blocking layer. The inorganic water-blocking layer is deposited through multiple reciprocating cycles. After the inorganic water-blocking layer is prepared, the roll is removed. Step 2: Prepare a copper mesh by etching or electroplating according to the design scheme, and then laminate the copper mesh to the side of the product with the adhesive film layer in a roll-to-roll manner to form a copper mesh circuit; Step 3: The product completed in Step 2 is used to prepare a camouflage layer with a pre-designed pattern on the inorganic water-blocking layer by means of nanoimprinting or thermal transfer, so as to obtain a composite water-blocking and conductive front film.

[0022] Furthermore, cooling rollers and extrusion rollers are installed after the roll-to-roll equipment chamber of the casting coating machine and before plasma-enhanced atomic layer deposition.

[0023] The substrate pre-film of this invention employs a PEALD (Plasma Enhanced Atomic Layer Deposition) method to prepare an inorganic water-blocking layer on one side of the substrate, and a TPO (Tissue Polymer Oxide) layer (adhesive film layer) on the other side using a cast-coating method. The two layers are processed in two chambers of a single device. In one chamber, the PEALD process is used to prepare the inorganic water-blocking layer, while in the other chamber, the cast-coating method is used to prepare the TPO layer. Since PEALD requires multiple cycles (precursor A injection-purge-precursor B injection-purge), while cast-coating of the TPO layer only requires a single cycle, after the first roll-to-roll process, the casting head in the TPO layer preparation chamber is closed, and the rolls are then repeatedly rolled-to-roll for PEALD preparation. This process simplifies the steps and reduces processing time, and the roll-to-roll format is more suitable for large-scale production.

[0024] A flexible CIGS solar cell is prepared using the aforementioned composite water-blocking and conductive front film; The preparation steps are as follows: The cut CIGS solar cells are placed on the side of the composite water-blocking and conductive front film with copper mesh. CIGS cells are welded together with a composite water-blocking and conductive front film using a continuous laser with a power of 100-150W. Then, the lamination process is carried out through a lamination equipment. Specifically, the laser-welded product is placed in the lamination equipment. At a temperature of 110℃, the upper chamber is kept under pressure and the lower chamber is evacuated for 60 seconds, the upper and lower chambers are evacuated for 480 seconds, the upper chamber is filled with gas and the lower chamber is evacuated for 180 seconds, the upper chamber is kept under pressure and the lower chamber is evacuated for 60 seconds, the upper chamber is kept under pressure and the lower chamber is evacuated for 360 seconds, the upper chamber is evacuated and the lower chamber is filled with gas for 50 seconds. This process effectively combines the battery cell and the copper mesh to prepare the module. The components are stacked in the following order: encapsulation protective film, adhesive film, composite water-blocking and conductive front film, CIGS battery and backsheet, and then laminated using a lamination device. The laminated product is cut into its final size using a laser cutting device. The cut product is then installed in a junction box to obtain a flexible CIGS solar cell.

[0025] The solar cell prepared in this invention uses a composite water-blocking and conductive front film layer prepared by PEALD (plasma-enhanced atomic layer deposition) to create a water-blocking layer (inorganic oxides, such as silicon oxide and aluminum oxide). PEALD technology can precisely deposit ultra-thin water-blocking films with uniformity and high sealing performance, effectively blocking moisture penetration and improving surface anti-fouling properties. This effectively prevents moisture from entering the photovoltaic module, preventing moisture from affecting cell performance and extending module lifespan. This layer replaces the original water-blocking film layer, ensuring the water and oxygen barrier function of the CIGS cell module to guarantee its long-term stability. It also reduces the use of the two layers (water-blocking film + EVA + ICI film) in the original structure, reducing the risk of composite failure between multilayer films (water-blocking film + EVA + ICI film) and increasing the long-term stability of the CIGS module. The single-layer film replacing the multilayer structure further reduces light reflection loss, thereby improving the photoelectric conversion efficiency and output power of the CIGS cell module.

[0026] The technical solution of the present invention is described in detail below.

[0027] First, this invention employs a composite water-blocking and conductive front film, and pre-assembles the composite water-blocking and conductive front film and CIGS battery into one unit; then, it is bonded to the encapsulation protective film and backsheet separately using adhesive films. This operation changes the traditional use of multiple adhesive films in the encapsulation protective film, water-blocking film, ICI film, CIGS battery and backsheet, thereby reducing the amount of adhesive film used. Given the relatively large weight of the adhesive film, this not only reduces the thickness and lightens the overall weight, but also increases the flexibility. The component thickness is reduced from 1200-1300μm in the original structure to 900-1000μm, and the cost can be reduced to meet the needs of new application markets such as portable devices.

[0028] Secondly, the technical solution of the present invention first prepares a composite water-blocking and conductive front film, and then laminates and encapsulates it with CIGS cells and backsheets, which reduces the adhesive film between the ICI film and the EVA layer in the original structure. Since the light transmittance of the two reduced film layers is about 90%, the light transmittance of the module is increased by 10%-15% by reducing them, and the photoelectric performance of the module is improved by about 3-10%.

[0029] Third, this invention abandons the traditional water-blocking membrane form and instead uses a composite water-blocking layer within a composite water-blocking conductive front film layer, reducing subsequent processes. At the same time, laser welding is used to combine the composite water-blocking conductive front film layer with the copper mesh circuit, which utilizes the adhesive properties of TPO to improve the long-term stability of photovoltaics.

[0030] Fourth, a composite anti-counterfeiting layer is constructed using nanoimprint technology. This process allows for pattern customization, providing personalized appearance designs, improving the appearance issues of traditional photovoltaic modules, and making them more aesthetically pleasing.

[0031] Fifth, the pre-film substrate employs a double-sided alternating processing technique, thereby simplifying the process and reducing time. Specifically, the TPO and water-blocking layer are processed simultaneously, improving work efficiency.

[0032] Sixth, in the double-sided preparation process of the substrate front film, due to the large temperature difference between plasma-enhanced atomic layer deposition of the water-blocking layer and cast coating of TPO, the plasma deposition temperature is 20-120℃, while the TPO layer is prepared by cast coating on one side at a temperature of 160-200℃. Since the two preparation methods require different temperatures, a cooling roller and an extrusion roller are added between the two chambers. This achieves the cooling and curing of the TPO layer while making the temperatures on both sides closer, and the unevenness on the front film substrate such as PET can be eliminated by extrusion.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) A composite water-blocking and conductive front film was prepared by alternating processing on both sides. This method of first composite bonding layer and then preparing inorganic water-blocking layer avoids the risk of damage to inorganic water-blocking layer caused by heating bonding layer. (2) Improve reliability. By assembling the inorganic water-blocking layer onto the substrate, not only can moisture penetration and oxidation be effectively prevented, and damage to photovoltaic modules caused by moisture, corrosion and environmental factors be prevented, but the use of encapsulation film (water-blocking film + EVA + ICI film) is also reduced, which reduces the risk of failure caused by the bonding of multiple encapsulation film layers (water-blocking film + EVA + ICI film). (3) Enhanced flexibility and portability: The composite water-blocking and conductive front film layer is prepared by using PEALD (plasma-enhanced atomic layer deposition) to replace the water-blocking film on the top of the original structure, thereby enhancing the lightness and flexibility of the module. This makes the photovoltaic module suitable for application scenarios with multiple bends and deformations, and meets the portability requirements. The low weight and high flexibility of the module make this technology widely applicable to mobile power systems, portable energy devices, building-integrated photovoltaics (BIPV) and other fields. (4) Reduce costs by adopting a composite water-blocking and conductive front film encapsulation scheme, using copper mesh instead of silver paste, and using PEALD (plasma-enhanced atomic layer deposition) to prepare a surface water-blocking layer instead of the original separate water-blocking film layer, which greatly reduces material and production costs, especially in large-scale production. At the same time, surface nanoimprinting replaces the traditional high-cost printing or coating process, further reducing the appearance design cost; (5) Optimize photoelectric performance. The nano-imprinted pattern used in the anti-counterfeiting layer not only enhances the appearance effect, but also reduces some light loss. The use of composite water-blocking and conductive front film reduces the light reflection loss caused by the use of encapsulation film (water-blocking film + EVA + ICI film), thereby improving the photoelectric conversion efficiency of CIGS module after encapsulation. (6) The double-sided alternating processing method simplifies the process and reduces working time. PEALD (plasma-enhanced atomic layer deposition) and casting coating equipment are combined and carried out simultaneously, thereby realizing double-sided processing, reducing energy consumption, and thus increasing efficiency. Attached Figure Description

[0034] Figure 1 The diagram shown is a schematic representation of the overall structure of the composite water-blocking and conductive front membrane of the present invention.

[0035] Figure 2 The following is a partial process diagram of the preparation of the composite water-blocking and conductive front film in this invention.

[0036] Figure 1 The structure consists of: 1. base layer, 2. inorganic water-blocking layer, 3. adhesive film layer, 4. copper mesh, and 5. anti-counterfeiting layer. Figure 2 In the middle: 6. Cast coating machine roll-to-roll equipment chamber, 7. Plasma-enhanced atomic layer deposition equipment chamber, 8. Cooling roller, 9. Extrusion roller. Detailed Implementation

[0037] The representative embodiments shown in the accompanying drawings will now be further refined. It should be understood that the following description is not intended to limit the embodiments to a single preferred embodiment. Rather, it is intended to cover alternatives, modifications, and equivalents that may be included within the substance and scope of the embodiments defined by the appended claims.

[0038] Based on the current problems of traditional flexible CIGS solar cells, our company provides a composite water-blocking and conductive front film suitable for flexible CIGS solar cells, the structure of which is as follows: Figure 1 As shown, the composite water-blocking and conductive front film includes a substrate, an inorganic water-blocking layer deposited on the upper surface of the substrate, and a copper mesh fixed to the lower surface of the substrate by an adhesive film layer. The inorganic water-blocking layer, the substrate, the adhesive film layer, and the copper mesh form an integral composite structure from top to bottom. In addition, a camouflage layer is also composited on the upper surface of the inorganic water-blocking layer.

[0039] The substrate is PET, PA, or PEN, and the adhesive film layer is TPO, PU, ​​or TPU. The inorganic water-blocking layer is prepared on the PET substrate by plasma-enhanced atomic layer deposition. The inorganic water-blocking layer is an inorganic oxide, specifically silicon oxide or aluminum oxide.

[0040] The above-mentioned composite water-blocking and conductive front film suitable for flexible CIGS solar cells is prepared by the following process: First, an adhesive film layer is applied to one side of the substrate using a casting coating machine, and then an inorganic water-blocking layer is deposited using plasma-enhanced atomic layer deposition. Then, a copper mesh is prepared by etching or electroplating, and the copper mesh is combined with the side of the substrate coated with an adhesive film layer to obtain a composite water-blocking and conductive front film.

[0041] Specifically, the steps for the above-mentioned composite water-blocking and conductive pre-film are as follows: Figure 2 As shown, the details are as follows: Step 1: An adhesive film layer is coated on one side of the substrate using a double-sided alternating processing method, while an inorganic water-blocking layer is deposited on the other side. Specifically, the substrate is passed through the roll-to-roll equipment chamber of a casting coating machine, where an adhesive film layer is coated on one side at a temperature of 160-200℃. Then, the substrate passes through the plasma-enhanced atomic layer deposition (PEA) chamber, where an inorganic water-blocking layer is deposited at a temperature of 20-120℃. This process is repeated multiple times. After the inorganic water-blocking layer is prepared, the roll is removed. Cooling rollers and extrusion rollers are installed after the roll-to-roll equipment chamber of the casting coating machine and before the PEA. The cooling rollers and extrusion rollers can reduce the temperature of the substrate to prevent it from affecting the coating during plasma deposition. Step 2: Prepare a copper mesh by etching or electroplating according to the design scheme, and then laminate the copper mesh to the side of the product with the adhesive film layer in a roll-to-roll manner to form a copper mesh circuit; Step 3: The product completed in Step 2 is used to prepare a camouflage layer with a pre-designed pattern on the inorganic water-blocking layer by means of nanoimprinting or thermal transfer, so as to obtain a composite water-blocking and conductive front film.

[0042] A flexible CIGS solar cell is fabricated using the aforementioned composite water-blocking and conductive front film. The fabrication steps are as follows: The cut CIGS solar cells are placed on the side of the composite water-blocking and conductive front film with copper mesh. CIGS cells are welded together with a composite water-blocking and conductive front film using a continuous laser with a power of 100-150W. Then, the lamination process is carried out through a lamination equipment. Specifically, the laser-welded product is placed in the lamination equipment. At a temperature of 110℃, the upper chamber is kept under pressure and the lower chamber is evacuated for 60 seconds, the upper and lower chambers are evacuated for 480 seconds, the upper chamber is filled with gas and the lower chamber is evacuated for 180 seconds, the upper chamber is kept under pressure and the lower chamber is evacuated for 60 seconds, the upper chamber is kept under pressure and the lower chamber is evacuated for 360 seconds, the upper chamber is evacuated and the lower chamber is filled with gas for 50 seconds. This process effectively combines the battery cell and the copper mesh to prepare the module. The components are stacked in the following order: encapsulation protective film, adhesive film, composite water-blocking and conductive front film, CIGS battery and backsheet, and then laminated using a lamination device. The laminated product is cut into its final size using a laser cutting device. The cut product is then installed in a junction box to obtain a flexible CIGS solar cell.

[0043] Compared with the prior art, which consists of ETFE film, EVA, water-blocking film, EVA, ICI film, CIGS battery, EVA and backsheet, the structure of the CIGS battery module prepared by the present invention is as follows: protective film (ETFE film), adhesive film (EVA), composite water-blocking and conductive front film, CIGS battery, adhesive film (EVA) and backsheet.

[0044] As can be seen from the comparison, the present invention obviously eliminates the EVA layer and directly composites the copper mesh with the substrate, thus eliminating the resin substrate layer of the ICI film.

[0045] The solar cell product prepared through the above steps has the following advantages: It has high reliability. The water-blocking layer is composited to the front film of the substrate, which effectively prevents moisture penetration and oxidation, reduces the use of encapsulation film layers, and reduces the risk of failure caused by the bonding of multiple encapsulation film layers. With better flexibility and portability, it replaces the original water-blocking film while reducing the use of encapsulation film (EVA film), reducing thickness, and enhancing the lightness and flexibility of the component, making the photovoltaic module suitable for applications with multiple bends and deformations. Costs were reduced by using copper mesh instead of silver paste and depositing a water-blocking layer instead of the original water-blocking film layer, which greatly reduced material and production costs, especially in large-scale production. Optimizing photoelectric performance reduces light reflection loss caused by the use of encapsulation layers (water-blocking film + EVA + ICI film), thereby improving the photoelectric conversion efficiency of the encapsulated CIGS module. It improves efficiency and increases benefits. Double-sided processing simplifies the process and reduces working time. PEALD (Plasma Enhanced Atomic Layer Deposition) and casting coating equipment are combined and carried out simultaneously, thereby achieving double-sided processing, reducing energy consumption, and thus increasing benefits.

[0046] It will be apparent to those skilled in the art that modifications, combinations, and variations can be made to the teachings described above.

Claims

1. A composite water-blocking and conductive front film suitable for flexible CIGS solar cells, characterized in that: The composite water-blocking and conductive front film includes a substrate, an inorganic water-blocking layer deposited on the upper surface of the substrate, and a copper mesh fixed on the lower surface of the substrate by an adhesive film layer. The inorganic water-blocking layer, the substrate, the adhesive film layer and the copper mesh are an integral composite structure from top to bottom.

2. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The substrate is made of polyethylene terephthalate, polyamide, polyethylene naphthalate, or polyimide.

3. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The adhesive film layer is made of polyethylene, polypropylene, propylene oxide, thermoplastic polyolefin, polyurethane, or thermoplastic polyurethane elastomer.

4. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The inorganic water-blocking layer is an inorganic oxide, specifically one of silicon oxide, fluoride, aluminum oxide, titanium dioxide, silicon nitride, silicon carbide, and zinc sulfide.

5. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The inorganic water-blocking layer is prepared on the substrate by plasma-enhanced atomic layer deposition.

6. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The composite water-blocking and conductive front film is coated with a camouflage layer.

7. The composite water-blocking and conductive front film suitable for flexible CIGS solar cells according to claim 1, characterized in that: The copper mesh is made of Cu-M alloy, wherein M is at least one metal selected from Zn, Al, Sn, and Ni, and the content of M is 1-2%.

8. A method for preparing a composite water-blocking and conductive front film suitable for flexible CIGS solar cells, characterized in that: Includes the following steps: First, a thermoplastic resin adhesive layer is coated on one side of the substrate using a casting coating machine, and then an inorganic water-blocking layer is deposited using plasma-enhanced atomic layer deposition. Then, a copper mesh is prepared by etching or electroplating, and the copper mesh is combined with the side of the substrate coated with a thermoplastic resin adhesive layer to obtain a composite water-blocking and conductive front film.

9. The preparation method according to claim 8, characterized in that: The specific steps are as follows: Step 1: A thermoplastic resin adhesive layer is coated on one side of the substrate using a double-sided alternating processing method, while an inorganic water-blocking layer is deposited on the other side. Specifically, the substrate is passed through the roll-to-roll equipment chamber of a casting coating machine, where a thermoplastic resin adhesive layer is coated on one side of the substrate at a temperature of 160-200℃. Then, the substrate is passed through the plasma-enhanced atomic layer deposition equipment chamber, where an inorganic water-blocking layer is deposited at a temperature of 20-120℃. The inorganic water-blocking layer is deposited through multiple reciprocating cycles. After the inorganic water-blocking layer is prepared, the roll is removed. Step 2: Prepare a copper mesh by etching or electroplating according to the design scheme, and then laminate the copper mesh to the side of the product with the thermoplastic resin adhesive layer in a roll-to-roll manner to form a copper mesh circuit. Step 3: The product completed in Step 2 is used to prepare a camouflage layer with a pre-designed pattern on the inorganic water-blocking layer by means of nanoimprinting or thermal transfer, so as to obtain a composite water-blocking and conductive front film.

10. The preparation method according to claim 9, characterized in that: Cooling rollers and extrusion rollers are installed after the roll-to-roll equipment chamber of the casting coating machine and before plasma-enhanced atomic layer deposition.

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