A cadmium telluride thin film photovoltaic module and method of making same

Abstract

This invention relates to the field of photovoltaic module technology and discloses a cadmium telluride thin-film photovoltaic module and its preparation method, comprising: providing a cadmium telluride cell layer, including at least a glass substrate, a front electrode layer, and an absorber layer stacked together; forming a contact layer on the side of the cadmium telluride cell layer near the absorber layer to form a first intermediate; stacking two first intermediates with the contact layers facing each other, and forming a sealant layer at the edge between the two glass substrates, the sealant layer being located on the side of the front electrode, cell layer, and contact layer to obtain a second intermediate; chemically thinning the two glass substrates in the second intermediate, the thinned glass substrates serving as the front glass; removing the area corresponding to the sealant layer to separate the second intermediate from the two contact layers to obtain two third intermediates; and forming a cadmium telluride thin-film photovoltaic module. This invention can improve the efficiency and yield of the chemical thinning process and improve the reliability of the cadmium telluride thin-film photovoltaic module.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module technology, specifically to a cadmium telluride thin-film photovoltaic module and its preparation method. Background Technology

[0002] The current main approach for producing flexible cadmium telluride (CdT) thin-film photovoltaic modules involves thinning CdT thin-film cells on a conventional thick glass substrate before bonding them to a flexible substrate. For example, CdT thin-film cells are currently fabricated on 2mm-3mm thick soda-lime glass, followed by chemical thinning of the glass substrate. This method has several problems: 1) Strong acids such as HF used in chemical thinning can damage the CdT thin-film cell layer, requiring additional protective materials and measures (e.g., acid-resistant protective films). This process is complex and costly. More importantly, existing protective films / inks and other materials on the market do not provide adequate long-term protection and cannot meet the requirements for glass thicknesses of 2mm or more. 2) During chemical thinning, the sample used for thinning gradually becomes thinner, increasing the difficulty, complexity, and substrate breakage rate, thus reducing the yield. Furthermore, large-area glass substrates thinned to the target thickness (e.g., 0.5mm) have low strength, exhibiting deformation and fragility, increasing the difficulty of subsequent processing of the thin glass. 3) Chemical etching is expensive, and the time required to thin a single glass substrate is often 10 hours or more, resulting in low process efficiency.

[0003] Therefore, a solution is needed that can effectively protect the cadmium telluride thin-film battery layer from damage during glass substrate thinning, while improving process efficiency and yield, and enhancing the reliability of cadmium telluride thin-film photovoltaic modules. Summary of the Invention

[0004] This invention provides a cadmium telluride thin-film photovoltaic module and its preparation method, which solves the problems in related technologies where chemical thinning of the glass substrate of cadmium telluride thin-film batteries damages the cadmium telluride thin-film battery film layer, and the chemical thinning process is difficult, has a high substrate breakage rate, low process efficiency, and low strength of the thinned glass substrate.

[0005] In a first aspect, the present invention provides a method for preparing a cadmium telluride thin-film photovoltaic module, the method comprising:

[0006] A cadmium telluride (CdTe) battery layer is provided; the CdTe battery layer includes at least a glass substrate, a front electrode layer, and an absorber layer stacked together. A contact layer is provided on the side of the cadmium telluride battery layer near the absorber layer to form a first intermediate; the glass substrate is located on the outermost side of the first intermediate; Two first intermediates are stacked face-to-face with the contact layers facing each other, and a sealant layer is formed at the edge between the two glass substrates. The sealant layer is located on the side of the front electrode layer, the side of the absorption layer and the side of the contact layer to obtain the second intermediate. The two glass substrates in the second intermediate are chemically thinned, and the thinned glass substrates are used as the front glass. Remove the area corresponding to the sealant layer to separate the second intermediate from the two contact layers, and obtain two third intermediates; Cadmium telluride thin-film photovoltaic modules are formed.

[0007] The method for fabricating a cadmium telluride thin-film photovoltaic module provided by this invention firstly involves stacking two first intermediates containing cadmium telluride cell layers and sealing their edges to form a second intermediate, exposing the glass substrates corresponding to the two cadmium telluride cell layers on their opposite outer sides. Next, the two glass substrates in the second intermediate are chemically thinned, and the thinned glass substrates serve as the front glass. Finally, the area corresponding to the sealant layer is removed, naturally separating the two third intermediates containing cadmium telluride cell layers. Firstly, forming the second intermediate after double-glass encapsulation and edge sealing avoids the need for an acid-resistant protective film and its destructive effect, ensuring that the film layers in the cadmium telluride cells are not damaged during chemical etching. Secondly, forming the second intermediate with the two first intermediates facing each other increases the overall thickness of the sample in the chemical thinning process, improving the process yield. Furthermore, simultaneously etching both glass substrates improves the efficiency of the chemical thinning process, doubling the yield. Thirdly, by removing the area corresponding to the sealant layer, the two third intermediates are naturally separated, which simplifies the process and avoids damage to the film layer in the cadmium telluride battery. Therefore, the method for preparing cadmium telluride thin-film photovoltaic modules provided by this invention can improve the efficiency and yield of the chemical thinning process and protect the film layer of the cadmium telluride thin-film battery from damage, thereby improving the reliability of the cadmium telluride thin-film photovoltaic module.

[0008] In one optional embodiment, the cadmium telluride battery layer is a finished cadmium telluride thin-film battery; the finished cadmium telluride thin-film battery includes a glass substrate, a front electrode layer, an absorber layer and a back electrode layer stacked together. The contact layer is a flexible substrate; The step of forming the first intermediate by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer includes: Provide flexible substrates and encapsulating films; An encapsulating film and a flexible substrate are sequentially disposed on the side of the back electrode layer facing away from the absorption layer; After lamination and encapsulation, a first intermediate is formed; the first intermediate includes a flexible substrate, an encapsulating film, and a cadmium telluride battery layer that are sequentially stacked and encapsulated.

[0009] The present invention provides a method for preparing a cadmium telluride thin-film photovoltaic module. The cadmium telluride cell layer is a finished cadmium telluride thin-film battery, and the contact layer is a flexible substrate. First, the finished cadmium telluride thin-film battery and the flexible substrate are laminated and encapsulated. Then, a second semi-finished product is formed for a chemical thinning process on the glass substrate. This means that the lamination and encapsulation process is placed before the chemical thinning process. On the one hand, this avoids the problem of reduced encapsulation yield after subsequent glass substrate thinning, reduces the breakage rate of the glass substrate, and improves the yield of the lamination and encapsulation process, thereby improving the reliability of the cadmium telluride thin-film photovoltaic module. On the other hand, the encapsulation film and the flexible substrate have a certain thickness, which can increase the overall thickness of the sample undergoing the chemical thinning process, providing support for the thinned glass substrate and improving the process yield.

[0010] In one alternative embodiment, the step of forming a cadmium telluride thin-film photovoltaic module includes: The third intermediate forms a cadmium telluride thin-film photovoltaic module; the cadmium telluride thin-film photovoltaic module includes a front glass, a front electrode layer, an absorber layer, a back electrode layer, an encapsulating film, and a flexible substrate stacked in sequence.

[0011] The method for preparing cadmium telluride thin-film photovoltaic modules provided by this invention allows for the natural separation of two flexible substrates after the area corresponding to the sealant layer is removed, thereby obtaining two cadmium telluride thin-film photovoltaic modules. This method simplifies the process, improves production efficiency, and reduces costs. At the same time, the encapsulating film and flexible substrates have good mechanical properties and flexibility, which can protect the thinned front glass during the subsequent transportation of the cadmium telluride thin-film photovoltaic modules.

[0012] In one optional embodiment, the cadmium telluride battery layer is a cadmium telluride thin-film battery semi-finished product; the cadmium telluride thin-film battery semi-finished product includes a glass substrate, a front electrode layer and an absorber layer stacked together; the contact layer is a protective layer. Following the chemical thinning step of the two glass substrates in the second intermediate, the process also includes: The front glass is chemically strengthened to make the surface stress of the front glass greater than or equal to 100MPa; the temperature of the chemical strengthening treatment is 400℃~500℃. The steps for forming cadmium telluride thin-film photovoltaic modules include: Remove the contact layer from each third intermediate; A back electrode layer is formed on one side surface of the absorber layer away from the front electrode layer to obtain a cadmium telluride thin-film battery; the cadmium telluride thin-film battery includes a front plate glass, a front electrode layer, an absorber layer, a back contact layer and a back electrode layer stacked in sequence. An encapsulating film and a flexible substrate are sequentially disposed on the side of the back electrode layer facing away from the absorption layer; After lamination and encapsulation, cadmium telluride thin-film photovoltaic modules are formed.

[0013] The present invention provides a method for preparing a cadmium telluride thin-film photovoltaic module. The cadmium telluride cell layer is a cadmium telluride thin-film cell semi-finished product. First, the two glass substrates in the second intermediate are chemically thinned, then the front glass is chemically strengthened, and finally the back electrode layer is formed to form a complete cadmium telluride thin-film cell. The cell is then laminated and encapsulated with a flexible substrate to form a cadmium telluride thin-film photovoltaic module. On the one hand, placing the formation of the back electrode layer after the chemical strengthening process of the front glass can avoid damage to the back electrode layer caused by the high temperature (400℃~500℃) of the chemical strengthening process. While achieving high-temperature chemical strengthening of the glass substrate, it eliminates the damage to the cadmium telluride thin-film battery material caused by the high temperature and chemical reagents in the chemical strengthening process, thereby improving the reliability of cadmium telluride thin-film photovoltaic modules. On the other hand, the strength of the front glass after chemical strengthening is significantly improved, with a stress of 100MPa or more, making it less prone to breakage. This can avoid the problem of thin front glass breaking during subsequent lamination and encapsulation with flexible substrates, improve the yield of the lamination and encapsulation process, eliminate the risk of breakage during photovoltaic module production, improve the production yield of cadmium telluride thin-film photovoltaic modules, improve the reliability and weather resistance of cadmium telluride thin-film photovoltaic modules, and meet the safety specifications of application scenarios such as buildings and automobiles.

[0014] In one optional embodiment, the cadmium telluride thin-film battery further includes a back contact layer located between the absorber layer and the back electrode layer. The steps for forming a back electrode layer on one side surface of the absorber layer away from the front electrode layer to obtain a cadmium telluride thin-film battery include: The absorption layer is activated. A back contact layer and a back electrode layer are formed on one side surface of the absorber layer away from the front electrode layer to obtain a cadmium telluride thin-film battery; the cadmium telluride thin-film battery includes a front plate glass, a front electrode layer, an absorber layer, a back contact layer and a back electrode layer stacked in sequence.

[0015] The method for preparing cadmium telluride thin-film photovoltaic modules provided by this invention involves chemically strengthening the front glass and removing the protective layer, followed by activating the absorber layer, forming the back contact layer, and forming the back electrode layer. This method avoids damage to the absorber layer, back contact layer, and back electrode layer caused by the high-temperature chemical strengthening process, thereby improving the reliability of the cadmium telluride thin-film battery.

[0016] In one optional embodiment, the chemical enhancement treatment uses a solution comprising potassium nitrate; the chemical enhancement treatment time is 1 to 10 hours. The protective layer comprises a first protective layer and a second protective layer stacked together; The step of forming the first intermediate by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer includes: A first protective layer and a second protective layer are sequentially formed on the side of the absorber layer away from the front electrode layer; the first protective layer is an inorganic oxide film; the second protective layer is a UV adhesive; the inorganic oxide film includes ZnO; The thickness of the first protective layer is 100~1000nm; the thickness of the second protective layer is 1μm~20μm.

[0017] The method for preparing a cadmium telluride thin-film photovoltaic module provided by this invention includes a protective layer that protects the absorber layer in the two cadmium telluride thin-film battery semi-finished products from damage when two first intermediates are forming a second intermediate. Simultaneously, the protective layer comprises a stacked first protective layer and a second protective layer, wherein the first protective layer is relatively closer to the absorber layer. The first protective layer protects the absorber layer from oxidation, while the second protective layer prevents the penetration and diffusion of potassium nitrate during the chemical strengthening process. This improves the reliability of the third intermediate while increasing the surface stress of the front glass, thereby enhancing the reliability and strength of the cadmium telluride thin-film photovoltaic module.

[0018] In one optional embodiment, the encapsulating film is made of PVB, EVA, or SGP, and the thickness of the encapsulating film is 0.1 mm to 1 mm. The flexible substrate is made of PET, PI, stainless steel or Mo, and the thickness of the flexible substrate is 0.1mm~1mm; The lamination and encapsulation temperature is 130℃~150℃.

[0019] In one alternative embodiment, in the cadmium telluride battery layer, each edge of the glass substrate extends beyond the edge of the front electrode layer and the edge of the absorber layer. The sealant layer material includes hot-melt polytetrafluoroethylene adhesive, butyl adhesive, or silicate inorganic adhesive; the width of the sealant layer corresponding to each edge of the glass substrate is 5mm~30mm; The steps for removing the sealant layer in the corresponding area include: The edge areas corresponding to each side of the third intermediate are removed by mechanical cutting or laser cutting, completely removing the area corresponding to the sealant layer; the width of the edge area corresponding to each side is greater than the width of the sealant layer; wherein, the cutting surface is perpendicular to the plane where the front glass is located.

[0020] The method for preparing cadmium telluride thin-film photovoltaic modules provided by this invention relies mainly on the sealing and fixing of the two first intermediates by the edge sealant layer. Therefore, during separation, the sealing layer at the edge is removed by laser and mechanical cutting, thereby separating the middle part. This simplifies the process and avoids damage to the structural layers in the third intermediate, thus improving the yield and reliability of the cadmium telluride thin-film photovoltaic modules.

[0021] In one optional embodiment, the thickness of the glass substrate in the cadmium telluride battery layer is 2 mm to 4 mm; Methods for chemically thinning the two glass substrates in the second intermediate include: Two glass substrates positioned opposite each other in the second intermediate were chemically etched simultaneously for 1 to 10 hours using an HF solution with a concentration of 1% to 30%; the thickness of the glass substrates after chemical thinning was 0.1 mm to 1 mm. The thickness of the front glass is 0.1mm to 1mm.

[0022] In a second aspect, the present invention provides a cadmium telluride thin-film photovoltaic module, which is prepared according to the preparation method of the cadmium telluride thin-film photovoltaic module described in the first aspect above. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic flowchart of a method for preparing a cadmium telluride thin-film photovoltaic module according to an embodiment of the present invention. Figure 2 This is a schematic flowchart illustrating a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the structure of the cadmium telluride battery layer in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the structure of a flexible substrate formed in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the structure of the first intermediate formed in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the structure after chemical thinning of two glass substrates in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention. Figure 7 This is a schematic diagram of the structure of the region corresponding to the removal of the sealant layer in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the structure of two third intermediates obtained in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention; Figure 9This is a schematic diagram of the structure of a cadmium telluride thin-film photovoltaic module in a method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 1 of the present invention. Figure 10 This is a schematic flowchart illustrating another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 11 This is a schematic diagram of the cadmium telluride battery layer in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 12 This is a schematic diagram of the structure forming a protective layer in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention; Figure 13 This is a schematic diagram of the structure of the first intermediate formed in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention; Figure 14 This is a schematic diagram of the structure after chemical thinning of two glass substrates in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 15 This is a schematic diagram of the structure of the region corresponding to the removal of the sealant layer in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 16 This is a schematic diagram of the structure of two third intermediates obtained in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 17 This is a schematic diagram of the structure of each third intermediate in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention; Figure 18 This is a schematic diagram of the structure for removing the protective layer in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention; Figure 19 This is a schematic diagram of the structure of the back electrode layer formed in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 20 This is a schematic diagram of the structure of a cadmium telluride thin-film photovoltaic module formed in another method for preparing a cadmium telluride thin-film photovoltaic module according to Embodiment 2 of the present invention. Figure 21A This is a schematic diagram of the damage to the cadmium telluride thin-film photovoltaic module obtained in Comparative Example 1. Figure 21B This is a schematic diagram of the damage to the cadmium telluride thin-film photovoltaic module obtained in Comparative Example 1. Figure 21C This is a schematic diagram of the damage to the cadmium telluride thin-film photovoltaic module obtained in Comparative Example 1.

[0025] Figure label: 10. Glass substrate; 11. Front electrode layer; 12. Absorber layer; 13. Back contact layer; 14. Back electrode layer; 20. Flexible substrate; 21. Encapsulating film; 30. Protective layer; 31. First protective layer; 32. Second protective layer; 40. Sealant layer; 100. First intermediate; 200. Second intermediate; 300. Third intermediate; 400. Cadmium telluride thin-film photovoltaic module. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the invention and not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] In the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These drawings are not to scale, and some details are enlarged for clarity, and some details may be omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0028] Lightweight, flexible cadmium telluride thin-film photovoltaic modules have numerous applications; however, their manufacturing process presents several challenges. Unlike flexible perovskite thin-film photovoltaic modules, high-efficiency cadmium telluride photovoltaic modules require high-temperature manufacturing processes, with substrate temperatures reaching 400°C. o C~700 oC. Currently used organic substrates such as PET are incompatible with high-temperature processes. Furthermore, unlike flexible CIGS thin-film photovoltaic modules, cadmium telluride (CdT) thin-film photovoltaic cells cannot be deposited on flexible substrates such as stainless steel (CdT cell structure differs from CIGS cell structure; if a similar structure is used, CdT cell efficiency is significantly reduced). Currently, research on lightweight flexible CdT thin-film photovoltaic modules mainly focuses on thin glass substrates, such as 0.01mm~1mm cornic borosilicate glass. However, with the significant increase in module size, such as 1215mm x 2300mm, the easily deformable nature of thin glass, especially the problem of large deformation at high temperatures, hinders its industrialization and development.

[0029] The current main approach for producing flexible cadmium telluride (CdT) thin-film photovoltaic modules involves thinning CdT thin-film cells on a conventional thick glass substrate before bonding them to a flexible substrate. For example, CdT thin-film cells are currently fabricated on 2mm-3mm thick soda-lime glass, followed by chemical thinning of the glass substrate. This method has several problems: 1) Strong acids such as HF used in chemical thinning can damage the CdT thin-film cell layer, requiring additional protective materials and measures (e.g., acid-resistant protective films). This process is complex and costly. More importantly, existing protective films / inks and other materials on the market do not provide adequate long-term protection and cannot meet the requirements for glass thicknesses of 2mm or more. 2) During chemical thinning, the sample used for thinning gradually becomes thinner, increasing the difficulty, complexity, and substrate breakage rate, thus reducing the yield. Furthermore, large-area glass substrates thinned to the target thickness (e.g., 0.5mm) have low strength, exhibiting deformation and fragility, increasing the difficulty of subsequent processing of the thin glass. 3) Chemical etching is expensive, and the time required to thin a single glass substrate is often 10 hours or more, resulting in low process efficiency.

[0030] Therefore, a solution is needed that can effectively protect the cadmium telluride thin-film battery layer from damage during glass substrate thinning, while improving process efficiency and yield, and enhancing the reliability of cadmium telluride thin-film photovoltaic modules.

[0031] like Figure 1 As shown, this embodiment provides a method for preparing a cadmium telluride thin-film photovoltaic module, which includes, but is not limited to, steps S101 to S106. The following references... Figures 2-20 Please provide a detailed explanation.

[0032] Step S101, providing a cadmium telluride battery layer; the cadmium telluride battery layer includes at least a stacked glass substrate 10, a front electrode layer 11, and an absorber layer 12, such as... Figure 3 or Figure 11 As shown.

[0033] In step S102, a contact layer is formed on the side of the cadmium telluride battery layer near the absorber layer 12, thus forming a first intermediate 100; the glass substrate 10 is located on the outermost side of the first intermediate 100, such as... Figure 4 or Figure 12 As shown.

[0034] Step S103: Two first intermediates 100 are stacked face-to-face with their contact layers facing each other, and a sealant layer 40 is formed at the edge between the two glass substrates 10. The sealant layer 40 is located on the side of the front electrode layer 11, the side of the absorber layer 12, and the side of the contact layer, thus obtaining the second intermediate 200. Figure 5 or Figure 13 As shown.

[0035] Step S104 involves chemically thinning the two glass substrates 10 in the second intermediate 200. The thinned glass substrates 10 serve as the front glass, such as... Figure 6 or Figure 14 As shown.

[0036] Step S105: Remove the area corresponding to the sealant layer 40, separate the second intermediate 200 from the two contact layers, and obtain two third intermediates 300, as shown. Figure 8 or Figure 16 As shown.

[0037] Step S106, forming a cadmium telluride thin-film photovoltaic module 400, such as Figure 9 or Figure 20 As shown.

[0038] The method for fabricating a cadmium telluride thin-film photovoltaic module provided in this embodiment firstly involves stacking two first intermediates containing cadmium telluride cell layers and sealing their edges to form a second intermediate, exposing the glass substrates corresponding to the two cadmium telluride cell layers on their opposite outer sides. Next, the two glass substrates in the second intermediate are chemically thinned, and the thinned glass substrates serve as the front glass. Finally, the area corresponding to the sealant layer is removed, naturally separating the two third intermediates containing cadmium telluride cell layers. Firstly, forming the second intermediate after double-glass encapsulation and edge sealing avoids the need for an acid-resistant protective film and its damaging effect, ensuring that the film layers in the cadmium telluride cells are not damaged during chemical etching. Secondly, forming the second intermediate with the two first intermediates facing each other as contact layers before thinning increases the overall thickness of the sample in the chemical thinning process, improving the process yield. Furthermore, simultaneously etching both glass substrates improves the efficiency of the chemical thinning process, doubling the yield. Thirdly, by removing the area corresponding to the sealant layer, the two third intermediates can be naturally separated, simplifying the process and avoiding damage to the film layer in the cadmium telluride battery. Therefore, the method for preparing cadmium telluride thin-film photovoltaic modules provided in this embodiment can improve the efficiency and yield of the glass substrate thinning process and protect the film layer of the cadmium telluride thin-film battery from damage, thereby improving the reliability of the cadmium telluride thin-film photovoltaic module.

[0039] In practice, the sealant layer 40 is located between the edges of the two glass substrates 10; a sealed space is formed between the two glass substrates 10 and the sealant layer 40, and the front electrode, the absorption layer 12 and the contact layer are located in the sealed space.

[0040] In some alternative embodiments, the sealant layer 40 covers the sides of the front electrode layer 11, the sides of the absorber layer 12, and the sides of the contact layer. In other alternative embodiments, there is a gap between the sealant layer 40 and the sides of the front electrode / absorber layer 12 / contact layer.

[0041] In some alternative implementations, such as Figure 3 As shown, the cadmium telluride battery layer is a finished cadmium telluride thin-film battery; the finished cadmium telluride thin-film battery includes a glass substrate 10, a front electrode layer 11, an absorber layer 12 and a back electrode layer 14 stacked together. The contact layer is a flexible substrate 20; The step of forming the first intermediate 100 by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer 12 includes: A flexible substrate 20 and an encapsulating film 21 are provided; An encapsulating film 21 and a flexible substrate 20 are sequentially disposed on the side of the back electrode layer 14 facing away from the absorption layer 12, such as Figure 4 As shown; After lamination and encapsulation, a first intermediate 100 is formed; the first intermediate 100 includes a flexible substrate 20, an encapsulating film 21, and a cadmium telluride battery layer that are sequentially laminated and encapsulated, such as... Figure 4 As shown.

[0042] In some optional embodiments, after forming the first intermediate 100, two first intermediates 100 are stacked face-to-face with the flexible substrate 20, and a sealant layer 40 is formed at the edge between the two glass substrates 10. The sealant layer 40 is located on the side of the front electrode layer 11, the side of the absorber layer 12, the side of the back electrode layer 14, the side of the encapsulating film 21, and the side of the flexible substrate 20, to obtain the second intermediate 200, such as... Figure 5 As shown.

[0043] In some alternative implementations, after obtaining the second intermediate 200, such as Figure 6 As shown, the two glass substrates 10 in the second intermediate 200 are chemically thinned, and the thinned glass substrates 10 serve as the front glass.

[0044] In some alternative embodiments, after chemical thinning, the area corresponding to the sealant layer 40 is removed along the cutting line L, such as... Figure 7 As shown; the two flexible substrates 20 will naturally separate, resulting in two third intermediates 300, as... Figure 8 As shown.

[0045] The method for preparing a cadmium telluride thin-film photovoltaic module provided in this embodiment uses a finished cadmium telluride thin-film battery as the cadmium telluride cell layer and a flexible substrate as the contact layer. First, the finished cadmium telluride thin-film battery and the flexible substrate are laminated and encapsulated. Then, a second semi-finished product is formed for a chemical thinning process on the glass substrate. This means that the lamination and encapsulation process is placed before the chemical thinning process. On the one hand, this avoids the problem of reduced encapsulation yield after subsequent glass substrate thinning, improving the yield of the lamination and encapsulation process and thus improving the reliability of the cadmium telluride thin-film photovoltaic module. On the other hand, the encapsulation film and the flexible substrate have a certain thickness, which can increase the overall thickness of the sample undergoing the chemical thinning process, providing support for the thinned glass substrate and improving the process yield.

[0046] In some alternative embodiments, the steps of forming the cadmium telluride thin-film photovoltaic module 400 include: as follows Figure 9 As shown, each third intermediate 300 is a cadmium telluride thin-film photovoltaic module 400; the cadmium telluride thin-film photovoltaic module 400 includes a front panel glass, a front electrode layer 11, an absorber layer 12, a back electrode layer 14, an encapsulating film 21 and a flexible substrate 20 stacked in sequence.

[0047] The method for preparing cadmium telluride thin-film photovoltaic modules provided in this embodiment allows for the natural separation of two flexible substrates after the area corresponding to the sealant layer is removed, resulting in two cadmium telluride thin-film photovoltaic modules. This method simplifies the process, improves production efficiency, and reduces costs. At the same time, the encapsulating film and flexible substrates possess good mechanical properties and flexibility, which can protect the thinned front glass during the subsequent transportation of the cadmium telluride thin-film photovoltaic modules.

[0048] In some alternative embodiments, the thickness of the glass substrate 10 in the cadmium telluride battery layer is 2 mm to 4 mm; the thickness of the front glass obtained after chemical thinning is 0.1 mm to 1 mm. In some optional embodiments, the thickness of the glass substrate 10 in the cadmium telluride battery layer is 2mm to 4mm; the thickness of the front glass obtained after chemical thinning is 0; that is, the glass substrate 10 is completely removed by chemical thinning; the final third intermediate 300, namely the cadmium telluride thin-film photovoltaic module 400, includes a front electrode layer 11, an absorber layer 12, a back electrode layer 14, an encapsulating film 21, and a flexible substrate 20 stacked sequentially.

[0049] In some optional embodiments, the cadmium telluride battery layer is a cadmium telluride thin-film battery semi-finished product; the cadmium telluride thin-film battery semi-finished product includes a glass substrate 10, a front electrode layer 11, and an absorber layer 12 stacked together, such as... Figure 11 As shown; in some optional embodiments, a contact layer is provided on the side of the cadmium telluride battery layer near the absorber layer 12. The contact layer is a protective layer 30, forming a first intermediate 100, such as... Figure 12 As shown.

[0050] In some alternative embodiments, after forming the first intermediate 100, two first intermediates 100 are stacked face-to-face with the protective layer 30, and a sealant layer 40 is formed at the edge between the two glass substrates 10. The sealant layer 40 is located on the side of the front electrode layer 11, the side of the absorber layer 12, and the side of the protective layer 30, to obtain the second intermediate 200, such as... Figure 13 As shown.

[0051] In some alternative implementations, after obtaining the second intermediate 200, such as Figure 14 As shown, the two glass substrates 10 in the second intermediate 200 are chemically thinned, and the thinned glass substrates 10 serve as the front glass.

[0052] In some optional embodiments, after the step of chemically thinning the two glass substrates 10 in the second intermediate 200, the method further includes: chemically strengthening the front glass so that the surface stress of the front glass is greater than or equal to 100 MPa; the temperature of the chemical strengthening treatment is 400°C to 500°C.

[0053] In some alternative embodiments, after chemical strengthening treatment, the area corresponding to the sealant layer 40 is removed along the cutting line L, such as... Figure 15 As shown; the two protective layers 30 will naturally separate, resulting in two third intermediates 300, as... Figure 16 As shown.

[0054] In some alternative embodiments, the steps of forming the cadmium telluride thin-film photovoltaic module 400 include: Remove the contact layer in each third intermediate 300, such as Figure 17 and Figure 18 As shown; A back electrode layer 14 is formed on the side surface of the absorber layer 12 opposite to the front electrode layer 11, resulting in a cadmium telluride thin-film battery. The cadmium telluride thin-film battery comprises a front glass panel, a front electrode layer 11, an absorber layer 12, a back contact layer 13, and a back electrode layer 14, sequentially stacked. Figure 19 As shown; An encapsulating film 21 and a flexible substrate 20 are sequentially disposed on the side of the back electrode layer 14 facing away from the absorption layer 12. After lamination and encapsulation, a cadmium telluride thin-film photovoltaic module 400 is formed, such as... Figure 20 As shown.

[0055] In related technologies, in the fabrication process of cadmium telluride thin-film batteries, if the glass substrate 10 is chemically strengthened before the cadmium telluride thin-film battery is formed, the glass substrate 10 will be susceptible to damage during high-temperature battery processes (e.g., the temperature during the deposition of the absorber layer is 500-600°C). o C) After that, there is basically no strengthening effect. If the cadmium telluride thin-film battery is formed first, and then chemical strengthening treatment is performed, the chemical strengthening treatment temperature (400~500) will be reduced. o C) and chemical reagents (KNO3) can affect and damage the performance of cadmium telluride thin-film batteries.

[0056] Since the high-temperature chemical strengthening after the deposition of the absorber layer 12 has little impact on the absorber layer 12 and the preceding processes and film layers, that is, the temperature of chemical strengthening has little impact on the semi-finished product, but has a significant impact on subsequent processes such as the activation of the absorber layer 12 and the formation of the back electrode layer 14, the cadmium telluride thin-film battery semi-finished product is formed first, then the glass substrate is thinned and strengthened, and finally the back electrode layer 14 is formed.

[0057] Furthermore, it is currently difficult to fabricate cadmium telluride thin-film batteries using large-area ultrathin glass because ultrathin glass is prone to deformation and breakage. If a thicker glass is used for strengthening before thinning, the chemical strengthening of the glass is mainly concentrated at a depth of 10-20 μm on the glass surface. Strengthening before thinning will remove the strengthened portion, resulting in the thinned glass substrate having no strengthening effect.

[0058] The method for preparing a cadmium telluride thin-film photovoltaic module provided in this embodiment involves using a cadmium telluride cell layer as a semi-finished cadmium telluride thin-film cell. First, the two glass substrates in the second intermediate are chemically thinned, then the front glass is chemically strengthened, and finally a back electrode layer is formed to form a complete cadmium telluride thin-film cell. The cell is then laminated and encapsulated with a flexible substrate to form a cadmium telluride thin-film photovoltaic module. On the one hand, placing the formation of the back electrode layer after the chemical strengthening process of the front glass can avoid damage to the back electrode layer caused by the high temperature (400℃~500℃) of the chemical strengthening process. While achieving high-temperature chemical strengthening of the glass substrate, it eliminates the damage to the cadmium telluride thin-film battery material caused by the high temperature and chemical reagents in the chemical strengthening process, thereby improving the reliability of cadmium telluride thin-film photovoltaic modules. On the other hand, the strength of the front glass after chemical strengthening is significantly improved, with a stress of 100MPa or more, making it less prone to breakage. This can avoid the problem of thin front glass breaking during subsequent lamination and encapsulation with flexible substrates, improve the yield of the lamination and encapsulation process, eliminate the risk of breakage during photovoltaic module production, improve the production yield of cadmium telluride thin-film photovoltaic modules, improve the reliability and weather resistance of cadmium telluride thin-film photovoltaic modules, and meet the safety specifications of application scenarios such as buildings and automobiles.

[0059] In some alternative embodiments, the cadmium telluride thin-film battery further includes a back contact layer 13 located between the absorber layer 12 and the back electrode layer 14, such as... Figure 19 As shown.

[0060] In some alternative embodiments, the step of forming a back electrode layer 14 on the side surface of the absorber layer 12 opposite to the front electrode layer 11 to obtain a cadmium telluride thin-film battery includes: The absorption layer 12 is activated. A back contact layer 13 and a back electrode layer 14 are formed on the side surface of the absorber layer 12 opposite to the front electrode layer 11, resulting in a cadmium telluride thin-film battery. The cadmium telluride thin-film battery comprises a front glass panel, a front electrode layer 11, an absorber layer 12, a back contact layer 13, and a back electrode layer 14, sequentially stacked. Figure 19 As shown.

[0061] In specific implementation, in the fabrication process of cadmium telluride thin-film batteries, the absorption layer 12 is activated, the back contact layer 13 is formed, and the back electrode layer 14 is formed. After these three processes are completed, none of them can withstand the 400-500°C chemical strengthening treatment. o Temperature degradation, i.e., chemical strengthening treatment, has a significant adverse effect on subsequent processes such as activation of the absorber layer 12, formation of the back contact layer 13, and formation of the back electrode layer 14. Therefore, after the chemical strengthening treatment of the front glass, the processes of activating the absorber layer 12, forming the back contact layer 13, and forming the back electrode layer 14 are carried out.

[0062] The method for preparing cadmium telluride thin-film photovoltaic modules provided in this embodiment involves chemically strengthening the front glass and removing the protective layer, followed by activating the absorber layer, forming the back contact layer, and forming the back electrode layer. This avoids damage to the absorber layer, back contact layer, and back electrode layer caused by the high-temperature chemical strengthening process, thereby improving the reliability of the cadmium telluride thin-film battery.

[0063] In some optional embodiments, the solution used in the chemical enhancement treatment includes potassium nitrate; the chemical enhancement treatment time is 1 to 10 hours. The protective layer 30 includes a first protective layer 31 and a second protective layer 32 stacked together, wherein the first protective layer 31 is relatively closer to the absorber layer 12, such as Figure 12 As shown; The step of forming the first intermediate 100 by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer 12 includes: A first protective layer 31 and a second protective layer 32 are sequentially formed on the side of the absorber layer 12 opposite to the front electrode layer 11; the first protective layer 31 is an inorganic oxide film; the second protective layer 32 is a modified high-temperature resistant UV adhesive; the inorganic oxide film includes ZnO; The thickness of the first protective layer 31 is 100nm~1000nm; the thickness of the second protective layer 32 is 1μm~20μm.

[0064] In some alternative embodiments, the chemically enhanced treatment uses a 100% potassium nitrate solution.

[0065] In practice, since chemical strengthening is a high-temperature process that involves air oxidation, and the cadmium telluride absorber layer 12 is easily oxidized in a high-temperature air atmosphere, the first protective layer 31 is an inorganic oxide film (e.g., ZnO). ZnO can be used as an oxide protective layer material, which can effectively prevent the oxidation of the cadmium telluride absorber layer 12.

[0066] Meanwhile, the second protective layer 32 is a modified high-temperature resistant UV adhesive. This modified high-temperature resistant UV adhesive is an organic material that undergoes carbonization and decomposition at high temperatures. The carbonization and decomposition temperature of the second protective layer 32 is greater than 400°C. o C; Modified high-temperature resistant UV adhesive can prevent the penetration and diffusion of KNO3 during the chemical strengthening process.

[0067] The method for preparing a cadmium telluride thin-film photovoltaic module provided in this embodiment involves a protective layer that protects the absorber layer in the two cadmium telluride thin-film battery semi-finished products from damage during the formation of the second intermediate from the two first intermediates. Simultaneously, the protective layer comprises a stacked first protective layer and a second protective layer, wherein the first protective layer is relatively closer to the absorber layer. The first protective layer protects the absorber layer from oxidation, while the second protective layer prevents the penetration and diffusion of potassium nitrate during the chemical strengthening process. This improves the reliability of the third intermediate while increasing the surface stress of the front glass, thereby enhancing the reliability and strength of the cadmium telluride thin-film photovoltaic module.

[0068] In some optional embodiments, the material of the encapsulating film 21 is PVB, EVA or SGP, and the thickness of the encapsulating film 21 is 0.1mm to 1mm. The flexible substrate 20 is made of PET, PI, stainless steel or Mo, and the thickness of the flexible substrate 20 is 0.1mm to 1mm; The lamination and encapsulation temperature is 130℃~150℃.

[0069] In some alternative embodiments, the absorber layer 12 is a cadmium telluride absorber layer 12; the front electrode layer 11 is a transparent conductive layer.

[0070] In some alternative embodiments, in the cadmium telluride battery layer, each edge of the glass substrate 10 extends beyond the edge of the front electrode layer 11 and the edge of the absorber layer 12. The material of the sealant layer 40 includes any one of hot melt polytetrafluoroethylene adhesive, butyl adhesive, and silicate inorganic adhesive; the width of the sealant layer 40 corresponding to each side of the glass substrate 10 is 5mm to 30mm. The steps for removing the sealant layer 40 in the corresponding area include: The edge areas corresponding to each side of the third intermediate 300 are removed by mechanical cutting or laser cutting, and the corresponding areas of the sealant layer 40 are completely removed; the width of the edge area corresponding to each side is greater than the width of the sealant layer 40; wherein, the cutting surface is perpendicular to the plane where the front glass is located.

[0071] In practice, the sealant layer 40 is a corrosion-resistant and high-temperature-resistant layer. The width of the sealant layer 40 corresponding to each edge of the glass substrate 10 is 5mm to 30mm, which ensures the sealing of the second intermediate body 200 and avoids removing too much of the glass substrate 10 during subsequent cutting. At the same time, the width of the edge area corresponding to each edge is greater than or equal to the width of the sealant layer 40, which ensures that the corresponding area of ​​the sealant layer 40 can be completely removed.

[0072] The method for preparing cadmium telluride thin-film photovoltaic modules provided in this embodiment relies mainly on the sealing and fixing of the two first intermediates by the edge sealant layer. Therefore, during separation, the edge sealant layer is removed by laser and mechanical cutting, thereby separating the middle part. This simplifies the process and avoids damage to the structural layers in the third intermediate, thus improving the yield and reliability of the cadmium telluride thin-film photovoltaic modules.

[0073] In some alternative embodiments, the thickness of the glass substrate 10 in the cadmium telluride battery layer is 2 mm to 4 mm; The method for chemically thinning the two glass substrates 10 in the second intermediate 200 includes: Two glass substrates 10 positioned opposite each other in the second intermediate 200 were chemically etched simultaneously for 1 to 10 hours using an HF solution with a concentration of 1% to 30%; the thickness of the glass substrates 10 after chemical thinning was 0.1 mm to 1 mm. The thickness of the front glass is 0.1mm to 1mm.

[0074] In some alternative embodiments, the thickness of the glass substrate 10 in the cadmium telluride battery layer is 3.2 mm; the thickness of the glass substrate 10 (i.e., the front glass) after chemical thinning is 0.5 mm.

[0075] Example 1 like Figure 2 As shown, the present invention also provides a detailed flowchart of a method for preparing a cadmium telluride thin-film photovoltaic module, including but not limited to steps S201 to S207.

[0076] Step S201: Provide a cadmium telluride (CdT) battery layer; the CdT battery layer is a finished CdT thin-film battery; the finished CdT thin-film battery includes a glass substrate 10, a front electrode layer 11, an absorber layer 12, and a back electrode layer 14 stacked together, such as... Figure 3 As shown.

[0077] In a specific implementation, the thickness of the glass substrate 10 is 2mm to 4mm. The absorption layer 12 is a cadmium telluride absorption layer 12; the front electrode layer 11 is a transparent conductive layer. In some examples, a back contact layer 13 is also included between the absorption layer 12 and the back electrode layer 14.

[0078] Step S202: Provide a flexible substrate 20 and an encapsulating film 21; An encapsulating film 21 and a flexible substrate 20 are sequentially disposed on the side of the back electrode layer 14 of each cadmium telluride battery layer facing away from the absorber layer 12, such as... Figure 4 As shown.

[0079] In practice, the flexible substrate 20 serves as the contact layer. The encapsulating film 21 is made of PVB, EVA, or SGP, and its thickness is 0.1mm to 1mm. The flexible substrate 20 is made of PET, PI, stainless steel, or Mo, and its thickness is 0.1mm to 1mm.

[0080] Step S203: After lamination and encapsulation, a first intermediate 100 is formed; the first intermediate 100 includes a flexible substrate 20, an encapsulating film 21, and a cadmium telluride battery layer that are sequentially laminated and encapsulated; wherein, the glass substrate 10 is located on the outermost side of the first intermediate 100, such as... Figure 4 As shown.

[0081] In practice, the lamination and encapsulation temperature is 130℃~150℃.

[0082] In step S204, two first intermediate bodies 100 are stacked face-to-face with their contact layers facing each other, and a sealant layer 40 is formed at the edge between the two glass substrates 10. The sealant layer 40 is located on the side of the front electrode layer 11, the side of the absorber layer 12, the side of the encapsulation film 21, and the side of the flexible substrate 20, thus obtaining the second intermediate body 200. Figure 5 As shown.

[0083] In practice, the flexible substrate 20 serves as the contact layer, and the two first intermediate bodies 100 are stacked face-to-face with the flexible substrate 20 on top of each other. The material of the sealant layer 40 includes hot-melt polytetrafluoroethylene adhesive, butyl adhesive, or silicate inorganic adhesive; the width of the sealant layer 40 corresponding to each side of the glass substrate 10 is 5mm to 30mm.

[0084] Step S205 involves chemically thinning the two glass substrates 10 in the second intermediate 200. The thinned glass substrates 10 serve as the front glass, such as... Figure 6 As shown.

[0085] In practice, a HF solution with a concentration of 1% to 30% is used to chemically etch two glass substrates 10 that are positioned opposite each other in the second intermediate 200 for 1 to 10 hours; the thickness of the glass substrate 10 after chemical thinning is 0.1 mm to 1 mm; the thickness of the front glass is 0.1 mm to 1 mm.

[0086] Step S206: Using mechanical or laser cutting, remove the edge regions corresponding to each side of the second intermediate body 200 along the cutting line L, completely removing the regions corresponding to the sealant layer 40; the width of the edge region corresponding to each side is greater than or equal to the width of the sealant layer 40; wherein, the cutting surface is perpendicular to the plane of the front glass, such as... Figure 7 As shown.

[0087] Step S207: Separate the second intermediate 200 from the two contact layers to obtain two third intermediates 300, as follows: Figure 8 As shown; each third intermediate 300 forms a cadmium telluride thin-film photovoltaic module 400; the cadmium telluride thin-film photovoltaic module 400 includes a front panel glass, a front electrode layer 11, an absorber layer 12, a back electrode layer 14, an encapsulating film 21, and a flexible substrate 20 stacked sequentially, as shown. Figure 9 As shown.

[0088] In practice, since there is no bonding or fixation between the two flexible substrates 20, after the area corresponding to the sealant layer 40 is cut and removed, the two flexible substrates 20 will naturally separate to obtain two third intermediates 300, that is, two cadmium telluride thin-film photovoltaic modules 400.

[0089] Example 2 like Figure 10 As shown, the present invention also provides a specific flowchart of another method for preparing a cadmium telluride thin-film photovoltaic module, including but not limited to steps S301 to S311.

[0090] Step S301: Provide a cadmium telluride (CdTe) battery layer; the CdTe battery layer is a CdTe thin-film battery semi-finished product; the CdTe thin-film battery semi-finished product includes a glass substrate 10, a front electrode layer 11, and an absorber layer 12 stacked together, such as... Figure 11 As shown.

[0091] In step S302, a first protective layer 31 and a second protective layer 32 are sequentially formed on the side of the absorber layer 12 opposite to the front electrode layer 11, forming a first intermediate body 100; the contact layer is a protective layer 30, which includes the stacked first protective layer 31 and second protective layer 32; the glass substrate 10 is located on the outermost side of the first intermediate body 100, such as... Figure 12 As shown.

[0092] In specific implementation, the first protective layer 31 is an inorganic oxide film; the second protective layer 32 is a modified high-temperature resistant UV adhesive; the inorganic oxide film includes ZnO; the thickness of the first protective layer 31 is 100nm~1000nm; the thickness of the second protective layer 32 is 1μm~20μm.

[0093] In step S303, two first intermediate bodies 100 are stacked face-to-face with their contact layers facing each other, and a sealant layer 40 is formed at the edge between the two glass substrates 10. The sealant layer 40 is located on the side of the front electrode layer 11, the side of the absorber layer 12, and the side of the protective layer 30, thus obtaining the second intermediate body 200. Figure 13 As shown.

[0094] In practice, the contact layer is a protective layer 30, and the two first intermediate bodies 100 are stacked face-to-face with the second protective layer 32. The sealant layer 40 is made of hot-melt polytetrafluoroethylene adhesive, butyl adhesive, or silicate inorganic adhesive; the width of the sealant layer 40 corresponding to each side of the glass substrate 10 is 5mm to 30mm.

[0095] Step S304: Chemically thin the two glass substrates 10 in the second intermediate 200. The thinned glass substrates 10 serve as the front glass, such as... Figure 14 As shown.

[0096] In practice, a HF solution with a concentration of 1% to 30% is used to chemically etch two glass substrates 10 that are positioned opposite each other in the second intermediate 200 for 1 to 10 hours; the thickness of the glass substrate 10 after chemical thinning is 0.1 mm to 1 mm; the thickness of the front glass is 0.1 mm to 1 mm.

[0097] Step S305: The front glass is chemically strengthened to ensure that the surface stress of the front glass is greater than or equal to 100 MPa; the chemical strengthening temperature is 400℃~500℃. Figure 14 As shown.

[0098] Step S306: Using mechanical or laser cutting, remove the edge regions corresponding to each side of the third intermediate body 300 along the cutting line L, completely removing the corresponding areas of the sealant layer 40; the width of the edge region corresponding to each side is greater than the width of the sealant layer 40; wherein, the cutting surface is perpendicular to the plane of the front glass, such as... Figure 15 As shown.

[0099] Step S307: Separate the second intermediate 200 from the two contact layers to obtain two third intermediates 300, as follows: Figure 16 As shown.

[0100] Step S308, remove the contact layer in each third intermediate 300, such as Figure 17 and Figure 18 As shown.

[0101] In practical implementation, the structure of each third intermediate 300 is as follows: Figure 17 As shown. Remove the first protective layer 31 and the second protective layer 32 from each third intermediate 300, as follows: Figure 18 As shown.

[0102] Step S309: Activate the absorber layer 12; form a back contact layer 13 and a back electrode layer 14 on the side of the absorber layer 12 opposite to the front electrode layer 11 to obtain a cadmium telluride thin-film battery; the cadmium telluride thin-film battery includes a front glass panel, a front electrode layer 11, an absorber layer 12, a back contact layer 13, and a back electrode layer 14 stacked sequentially, as shown below. Figure 19 As shown.

[0103] Step S310: An encapsulating film 21 and a flexible substrate 20 are sequentially disposed on the side of the back electrode layer 14 facing away from the absorption layer 12, such as... Figure 20 As shown.

[0104] In specific implementation, the encapsulating film 21 is made of PVB, EVA or SGP, and the thickness of the encapsulating film 21 is 0.1mm to 1mm; the flexible substrate 20 is made of PET, PI, stainless steel or Mo, and the thickness of the flexible substrate 20 is 0.1mm to 1mm.

[0105] Step S311: After lamination and encapsulation, a cadmium telluride thin-film photovoltaic module 400 is formed.

[0106] In practice, the lamination and encapsulation temperature is 130℃~150℃.

[0107] To verify the effectiveness of the cadmium telluride thin-film photovoltaic module preparation method provided by this invention, this application provides Example 1, Example 2, and Comparative Example 1 to prepare different cadmium telluride thin-film photovoltaic modules. Example 1 is prepared by... Figure 2 Prepared by the method shown. Figure 9 This is a schematic diagram of the cadmium telluride thin-film photovoltaic module obtained through Example 1. Example 2 is obtained through... Figure 10 Prepared by the method shown. Figure 20 This is a schematic diagram of the cadmium telluride thin-film photovoltaic module obtained through Example 2. Comparative Example 1 shows a scheme for directly thinning the glass substrate of a single glass-based cadmium telluride cell using an acid-resistant protective film.

[0108] The preparation method provided in Comparative Example 1 includes: (1) providing a glass-based cadmium telluride battery; the glass-based cadmium telluride battery includes a glass substrate, a front electrode layer, an absorber layer and a back electrode layer, and the thickness of the glass substrate is 3.2 mm; (2) applying a special anti-acid protective film to the surface of the glass-based cadmium telluride battery (i.e., the surface of the back electrode layer); (3) chemically thinning the glass substrate in a 1%~30% HF solution for about 1 hour to 10 hours, reducing the thickness of the glass substrate from 3.2 mm to 0.5 mm, and using the thinned glass substrate as the front glass to obtain the cadmium telluride battery; (4) removing the anti-acid protective film; (5) removing the non-flat area of ​​5~10 mm at the edge by laser cutting; (6) sequentially stacking the cadmium telluride battery, a 0.5 mm thick PVB film and a 0.2 mm thick PET substrate, and performing 130°C treatment. o C~150 o C-laminated encapsulation.

[0109] The challenges and problems encountered in Comparative Example 1 include: ensuring that the thickness of the hot-bent hyperbolic glass is significantly greater than that of the 3.2 mm glass-based cadmium telluride thin-film battery, so that the 3.2 mm thick cadmium telluride thin-film battery can achieve hyperbolic molding along with the hot-bent hyperbolic glass during the encapsulation and shaping process, while the shape of the hyperbolic mold remains unaffected. The final double-glass photovoltaic module has a thickness of 3.2 mm + 0.76 mm + 10 mm, resulting in a significant increase in both thickness and weight.

[0110] Example 1 provides a preparation method including: (1) providing a cadmium telluride thin-film battery product, including a glass substrate, a front electrode layer, an absorber layer and a back electrode layer stacked together; the thickness of the glass substrate is 3.2 mm; (2) sequentially laying a cadmium telluride thin-film battery product, a PVB film with a thickness of 0.5 mm and a PET substrate with a thickness of 0.2 mm, and performing 130°C treatment. o C~150 o C-layer encapsulation to obtain the first intermediate; (3) stack the two first intermediates face to face with the flexible substrate, wherein anti-corrosion and high-temperature resistant adhesives are provided at the 10mm wide edge, including hot melt polytetrafluoroethylene adhesive, butyl adhesive and silicate inorganic adhesive, to achieve edge sealing and protection between the two first intermediates, and obtain the second intermediate; (4) simultaneously perform chemical etching of the glass substrates on both sides of the second intermediate with a concentration of 1%~30%HF for 1~10 hours, reducing the thickness of the glass substrate from 3.2mm to 0.5mm, and the thinned glass substrate is used as the front glass; (5) use laser cutting to remove the area with an edge width of 10mm, and separate the two third intermediates. Each third intermediate includes the front glass, front electrode layer, absorption layer, back electrode layer, PVB film and flexible substrate stacked in sequence, and each third intermediate is a cadmium telluride thin film photovoltaic module.

[0111] Example 2 provides a preparation method including: (1) providing a glass-based cadmium telluride thin-film battery semi-finished product, including a glass substrate, a front electrode layer and an absorption layer stacked together; (2) preparing a ZnO layer with a thickness of 200~500nm as a first protective layer and a high-temperature resistant UV adhesive with a thickness of 1~10μm as a second protective layer on the absorption layer to obtain a first intermediate; (3) stacking two first intermediates face to face in the manner of the second protective layer, wherein a sealing adhesive layer is provided at a position with a width of 10mm at the four edges, including hot-melt polytetrafluoroethylene adhesive, butyl adhesive and silicate inorganic adhesive, to achieve edge sealing and protection between the two first intermediates to obtain a second intermediate; (4) simultaneously performing 1%~30% HF and 1 hour~10 hours of chemical etching on both sides of the glass, reducing the thickness of the glass substrate from 3.2mm to 0.5mm, and using the thinned glass substrate as the front plate glass; (5) performing 400~500 oC and chemical strengthening treatment for 1~10 hours to make the surface stress of the front glass greater than or equal to 100MPa; (6) use laser cutting to remove the area with an edge width of 10 mm, separate the two third intermediates, each of which includes the front glass, front electrode layer, absorption layer, first protective layer and second protective layer stacked in sequence; (7) remove the first protective layer and the second protective layer; (8) activate the cadmium telluride thin film battery semi-finished product, form the back contact layer and deposit the back electrode layer; (9) sequentially lay the thinned and strengthened cadmium telluride thin film battery semi-finished product, a 0.5 mm thick PVB film and a 0.2 mm thick PET flexible substrate, and perform 130 o C-150 o C-lamination encapsulation forms a cadmium telluride thin-film photovoltaic module.

[0112] Disadvantages of Comparative Example 1: 1) A special acid-resistant protective film needs to be pasted onto the surface of the cadmium telluride battery film and removed after chemical thinning. However, existing special acid-resistant protective films have poor long-term resistance to HF corrosion, and HF can still penetrate the acid-resistant protective film, thereby corroding the cadmium telluride battery layer. Figure 21A As shown; simultaneously, the acid-resistant protective film can also damage the cadmium telluride film layer during subsequent removal. For example, due to the adhesive properties of the acid-resistant protective film, the cadmium telluride battery layer may be damaged during film peeling. Figure 21B As shown. 2) Glass substrates chemically thinned to 0.5 mm are fragile and may break during transportation, such as... Figure 21C As shown; in addition, the lamination and encapsulation of large-area 0.5mm glass-based cadmium telluride batteries / PVB film / PET flexible substrate is also a challenge, as it is prone to breakage and has a low yield.

[0113] Compared to Comparative Example 1, Example 1, by employing double glass and edge sealing, and a first intermediate consisting of a 3.2mm thick cadmium telluride thin-film battery product / PVB film / PET substrate, avoids the need for an acid-resistant protective film and its destructive effects, ensuring that the cadmium telluride battery film layer remains undamaged during chemical etching. It also allows for simultaneous etching of both sides of the glass, doubling the yield. Furthermore, Example 1, by using a first intermediate formed after laminating the cadmium telluride thin-film battery product / PVB film / PET substrate, moves the lamination and encapsulation process forward, avoiding the yield reduction problem associated with subsequent thinning to 0.5mm glass encapsulation. Finally, a third intermediate is laser-removed. This third intermediate includes the thinned cadmium telluride thin-film battery product / PVB film / PET substrate. The PVB film and PET substrate possess good mechanical properties and flexibility, protecting the thin glass substrate during transportation.

[0114] Example 2 achieves high-temperature chemical strengthening while eliminating the damage to cadmium telluride thin-film battery materials caused by high temperatures and chemical reagents; the front glass with a thickness of 0.5 mm after chemical strengthening has a stress of 100 MPa or more, increasing the material strength, eliminating the risk of breakage during the production of lightweight components, and meeting the safety specifications for applications such as buildings and automobiles.

[0115] This invention also provides a cadmium telluride thin-film photovoltaic module, prepared according to the above-described method for preparing a cadmium telluride thin-film photovoltaic module, such as... Figure 9 and Figure 20 As shown.

[0116] In the description of this specification, the references to terms such as "this embodiment," "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0117] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0118] The above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of protection of the present invention is determined by the scope of the appended claims.

Claims

1. A method for preparing a cadmium telluride thin-film photovoltaic module, characterized in that, The preparation method includes: A cadmium telluride battery layer is provided; the cadmium telluride battery layer includes at least a glass substrate, a front electrode layer, and an absorber layer stacked together. A contact layer is provided on the side of the cadmium telluride battery layer near the absorber layer to form a first intermediate; the glass substrate is located on the outermost side of the first intermediate. Two first intermediates are stacked face-to-face with the contact layer, and a sealant layer is formed at the edge between the two glass substrates. The sealant layer is located on the side of the front electrode layer, the side of the absorption layer and the side of the contact layer to obtain the second intermediate. The two glass substrates in the second intermediate are chemically thinned, and the thinned glass substrates are used as the front glass. Remove the area corresponding to the sealant layer, separate the second intermediate from the two contact layers, and obtain two third intermediates; Cadmium telluride thin-film photovoltaic modules are formed.

2. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 1, characterized in that, The cadmium telluride battery layer is a finished cadmium telluride thin-film battery; the finished cadmium telluride thin-film battery includes a glass substrate, a front electrode layer, an absorber layer and a back electrode layer stacked together; The contact layer is a flexible substrate; The step of forming the first intermediate by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer includes: Provide flexible substrates and encapsulating films; An encapsulating film and a flexible substrate are sequentially disposed on the side of the back electrode layer opposite to the absorption layer; After lamination and encapsulation, a first intermediate is formed; the first intermediate includes a flexible substrate, an encapsulating film, and a cadmium telluride battery layer that are sequentially stacked and encapsulated.

3. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 2, characterized in that, The steps for forming the cadmium telluride thin-film photovoltaic module include: The third intermediate forms a cadmium telluride thin-film photovoltaic module; the cadmium telluride thin-film photovoltaic module includes a front glass, a front electrode layer, an absorber layer, a back electrode layer, an encapsulating film, and a flexible substrate stacked in sequence.

4. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 1, characterized in that, The cadmium telluride battery layer is a cadmium telluride thin-film battery semi-finished product; the cadmium telluride thin-film battery semi-finished product includes a glass substrate, a front electrode layer and an absorption layer stacked together; the contact layer is a protective layer; Following the step of chemically thinning the two glass substrates in the second intermediate, the method further includes: The front glass is chemically strengthened to make the surface stress of the front glass greater than or equal to 100 MPa; the temperature of the chemical strengthening treatment is 400℃~500℃. The steps for forming the cadmium telluride thin-film photovoltaic module include: Remove the contact layer from each of the third intermediates; A back electrode layer is formed on the side surface of the absorber layer opposite to the front electrode layer to obtain a cadmium telluride thin-film battery; the cadmium telluride thin-film battery includes a front plate glass, a front electrode layer, an absorber layer, a back contact layer and a back electrode layer stacked in sequence. An encapsulating film and a flexible substrate are sequentially disposed on the side of the back electrode layer opposite to the absorption layer; After lamination and encapsulation, cadmium telluride thin-film photovoltaic modules are formed.

5. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 4, characterized in that, The cadmium telluride thin-film battery further includes a back contact layer located between the absorber layer and the back electrode layer; The step of forming a back electrode layer on the side surface of the absorber layer opposite to the front electrode layer to obtain a cadmium telluride thin-film battery includes: The absorption layer is activated. A back contact layer and a back electrode layer are formed on the side surface of the absorber layer opposite to the front electrode layer to obtain a cadmium telluride thin-film battery; the cadmium telluride thin-film battery includes a front plate glass, a front electrode layer, an absorber layer, a back contact layer and a back electrode layer stacked in sequence.

6. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 4, characterized in that, The chemical enhancement treatment uses a solution containing potassium nitrate; the chemical enhancement treatment time is 1 to 10 hours. The protective layer comprises a first protective layer and a second protective layer stacked together; The step of forming the first intermediate by setting a contact layer on the side of the cadmium telluride battery layer near the absorber layer includes: A first protective layer and a second protective layer are sequentially formed on the side of the absorber layer opposite to the front electrode layer; the first protective layer is an inorganic oxide film; the second protective layer is a UV adhesive; the inorganic oxide film includes ZnO; The thickness of the first protective layer is 100~1000nm; the thickness of the second protective layer is 1μm~20μm.

7. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 2 or 4, characterized in that, The encapsulating film is made of PVB, EVA or SGP, and the thickness of the encapsulating film is 0.1mm to 1mm. The flexible substrate is made of PET, PI, stainless steel or Mo, and the thickness of the flexible substrate is 0.1mm to 1mm. The lamination and encapsulation temperature is 130℃~150℃.

8. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 1, characterized in that, In the cadmium telluride battery layer, each edge of the glass substrate extends beyond the edge of the front electrode layer and the edge of the absorption layer; The sealant layer is made of hot melt polytetrafluoroethylene adhesive, butyl rubber, or silicate inorganic adhesive. The width of the sealant layer corresponding to each side of the glass substrate is 5mm to 30mm; The step of removing the corresponding area of ​​the sealant layer includes: The edge regions corresponding to each side of the third intermediate are removed by mechanical cutting or laser cutting, completely removing the corresponding regions of the sealant layer; the width of the edge region corresponding to each side is greater than the width of the sealant layer; wherein, the cutting surface is perpendicular to the plane where the front glass is located.

9. The method for preparing a cadmium telluride thin-film photovoltaic module according to claim 1, characterized in that, The thickness of the glass substrate in the cadmium telluride battery layer is 2mm~4mm; The method for chemically thinning the two glass substrates in the second intermediate includes: The two glass substrates positioned opposite each other in the second intermediate are chemically etched simultaneously for 1 to 10 hours using an HF solution with a concentration of 1% to 30%; the thickness of the glass substrates after chemical thinning is 0.1 mm to 1 mm. The thickness of the front glass panel is 0.1mm to 1mm.

10. A cadmium telluride thin-film photovoltaic module, characterized in that, The cadmium telluride thin-film photovoltaic module is prepared according to any one of claims 1 to 9.

Images