Preparation method of thin-film solar cell

Abstract

The invention relates to the field of photovoltaic cell preparation, in particular to a preparation method of a thin-film solar cell, which comprises the following steps: preparing a power generation layer on a substrate to obtain a cell chip; removing a certain width of the edge of the power generation layer; leading out the bus bar from the power generation layer; a rear packaging adhesive film and a back plate are sequentially placed on the side, away from the substrate, of the power generation layer in sequence and are aligned, and a stacked assembly is obtained; laminating the laminated assembly to obtain a laminated assembly; cutting the laminated assembly; and installing a junction box on the cut laminated assembly and communicating the junction box with the bus bar, and then testing. The cutting step is carried out after the laminating step, it is ensured that the fragile power generation layer is protected at the beginning of machining, pollution and damage to the power generation layer caused by follow-up procedures are completely eradicated, and the power generation layer can be prevented from being exposed to the external environment in the cutting process; the technical problems that the power generation layer is easily polluted during cutting and the power generation layer is easily damaged during mechanical cutting are fundamentally solved, so that the product yield and the long-term reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell fabrication, and specifically to a method for fabricating thin-film solar cells. Background Technology

[0002] Thin-film solar cells (such as copper indium gallium selenide (CIGS), cadmium telluride (CdTe), and perovskite) represent the next generation of photovoltaic technology. They form battery chips by depositing multiple layers of thin-film materials on substrates such as glass, flexible stainless steel, or polymers. Compared with traditional crystalline silicon cells, they have advantages such as good performance in low light conditions, low temperature coefficient, the ability to be made into flexible and semi-transparent modules, and a uniform and aesthetically pleasing appearance.

[0003] Current methods for preparing thin-film solar cells employ a "cut-then-laminate" process. After the cell chips are prepared, they are cut and edge-ground to the required dimensions according to the design dimensions of the target product, and then laminated to form a complete module.

[0004] However, the "cut-then-laminate" process has the following drawbacks: 1. Cutting can contaminate battery chips: During the cutting process, the debris and impurities generated can easily adhere to the surface of the power generation layer, affecting battery performance.

[0005] 2. Cutting can damage the power generation layer: During the cutting process, the cutting tool comes into contact with the power generation layer, which can easily cause micro-cracks or damage, reducing the battery conversion efficiency.

[0006] 3. Edge grinding process contaminates the power generation layer: Edge grinding requires grinding the cut edges, which also introduces impurities, contaminates the power generation layer, and further reduces battery performance. Summary of the Invention

[0007] In view of this, the present invention provides a method for preparing thin-film solar cells, aiming to solve the problem that the power generation layer is easily contaminated and damaged during the production process.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for fabricating a thin-film solar cell includes the following steps: fabricating a power generation layer on a substrate to obtain a cell chip; removing a certain width from the edge of the power generation layer; leading a busbar out from the power generation layer; sequentially placing and aligning a post-encapsulation film and a backsheet on the side of the power generation layer away from the substrate to obtain a laminated module; laminating the laminated module to obtain a laminated module; cutting the laminated module; installing a junction box on the cut laminated module and connecting it to the busbar, and then testing.

[0009] In some alternative embodiments, the pre-encapsulation film and cover plate are sequentially placed and aligned on the side of the substrate away from the power generation layer to obtain the laminated assembly; In some alternative implementations, after removing a certain width of the edge of the power generation layer, a sealant is applied to the substrate around the periphery of the power generation layer.

[0010] In some alternative implementations, after the laminated component is cut, the edges of the cut laminated component are ground.

[0011] In some alternative embodiments, the power generation layer includes a conductive layer, a window layer, an absorption layer, a back contact layer, and a back electrode arranged sequentially.

[0012] In some alternative embodiments, the conductive layer is a fluorine-doped tin oxide layer; the window layer is a cadmium sulfide layer or a cadmium selenide layer; the absorption layer is a cadmium telluride layer; the back contact layer is a zinc telluride layer; and the back electrode is a molybdenum layer.

[0013] In some alternative implementations, a power generation layer is prepared on a substrate using a vacuum deposition process, and the power generation layer is laser-etched to form a single-junction or multi-junction battery chip.

[0014] In some alternative implementations, a laser is used to plan a path along the edge of the power generation layer to remove a certain width of the edge.

[0015] In some alternative implementations, the laminated assembly is laminated in a vacuum and heated environment to obtain a laminated assembly.

[0016] In some alternative implementations, the laminated components are cut by water jet cutting, laser cutting, or mechanical cutting.

[0017] In summary, compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention places the cutting step after the lamination step, ensuring that the fragile power generation layer is protected from the beginning of processing, fundamentally eliminating the pollution and physical damage to the power generation layer caused by subsequent processes, and avoiding the power generation layer from being exposed to the external environment during the cutting process. This fundamentally solves the technical problems of the power generation layer being easily contaminated during cutting and easily damaged by mechanical cutting, thereby improving product yield and long-term reliability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the preparation method described in this invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, while "above," "below," "within," etc. are understood to include the stated number. If terms such as "first," "second," etc., are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] This invention introduces a method for preparing thin-film solar cells, such as... Figure 1 As shown, the main steps include S10 chip fabrication, S20 edge cleaning, S30 busbar laying, S40 wafer assembly, S50 lamination, S60 dicing, and S70 testing. Examples of each step are provided below.

[0024] S10 chip fabrication: A power generation layer is fabricated on a substrate to obtain a battery chip.

[0025] Optionally, in the S10 chip fabrication step, a vacuum deposition process can be used to sequentially deposit a conductive layer, a window layer, an absorption layer, a back contact layer, and a back electrode on, for example, a glass substrate. The glass substrate and the conductive layer together form a conductive glass, and the conductive layer, the window layer, the absorption layer, the back contact layer, and the back electrode together form a power generation layer.

[0026] Among them, single-junction or multi-junction battery chips can be formed on the power generation layer by means of laser etching, and standard large-area whole battery chips of 1.2m×1.6m can be produced.

[0027] Vacuum coating processes can employ methods such as close-spaced sublimation (CSS), vapor transport deposition (VTD), magnetron sputtering, vacuum evaporation, or chemical bath deposition.

[0028] The conductive layer can be a fluorine-doped tin oxide (FTO) layer.

[0029] The window layer can be a cadmium sulfide (CdS) layer or a cadmium selenide (CdSe) layer.

[0030] The absorber layer can be a cadmium telluride (CdTe) layer.

[0031] The back contact layer can be a zinc telluride (ZnTe) layer.

[0032] The back electrode can be a molybdenum (Mo) layer.

[0033] S20 edge clearing: Removes a certain width of the edge of the power generation layer.

[0034] A high-precision laser system (such as a green laser or an ultraviolet picosecond laser) can be used to travel along a planned path along the edge of the power generation layer to remove a certain width of the edge. The laser can vaporize or peel off 3mm to 15mm of the edge of the power generation layer, which can remove process defects and short-circuit channels at the edge of the power generation layer, improve the reliability of the finished product, and prepare for overall lamination.

[0035] The S20 edge clearing step deals with the outer part of the power generation layer and does not involve internal segmentation, thus avoiding debris contamination of the core power generation area of ​​the power generation layer.

[0036] S30 Busbar Installation: The busbar is led out from the power generation layer.

[0037] Busbars (usually tinned copper strips) are pressed or soldered onto the power generation layer and led out to provide a path for subsequent current extraction.

[0038] Optionally, during the S30 busbar laying step, a sealant (e.g., strip butyl rubber) can be precisely applied to the periphery of the power generation layer using, for example, automated adhesive applicator, to provide pre-sealing protection for the edges of the power generation layer.

[0039] S40 lamination: On the side of the power generation layer away from the substrate, the encapsulating film and backsheet are placed sequentially and aligned to obtain a laminated module.

[0040] Specifically, the backsheet, post-encapsulation film, and battery chips can be placed sequentially on a stacking worktable, so that the backsheet, post-encapsulation film, power generation layer, and substrate are arranged in sequence. This structure can produce a "double-glass photovoltaic module".

[0041] Alternatively, the front encapsulation film and cover plate can be placed sequentially and aligned on the side of the substrate away from the power generation layer to obtain the laminated module. Specifically, the back sheet, rear encapsulation film, battery chip, front encapsulation film, and cover plate can be placed sequentially and aligned on the lamination worktable, so that the back sheet, rear encapsulation film, power generation layer, substrate, front encapsulation film, and cover plate are arranged in sequence. This structure can obtain a "triple-glass photovoltaic module".

[0042] The back panel can be a glass plate or a polymer plate.

[0043] The materials used for the post-encapsulation film and the pre-encapsulation film are the same, such as polyethylene vinylacetate (EVA), polyolefin elastomer (POE), or polyvinyl butyral (PVB).

[0044] The cover is usually made of glass.

[0045] All materials maintain standard large-area dimensions, which is highly conducive to automated equipment (such as robotic arms and conveyor belts) grasping, conveying and precisely positioning them.

[0046] S50 lamination: Laminating stacked components to obtain laminated components.

[0047] The laminated assembly is fed into, for example, a large laminator. Under vacuum, heating melts the post-encapsulation film / pre-encapsulation film and sealant, while pressure is applied to force the molten film (post-encapsulation film / pre-encapsulation film and sealant) to fill all gaps and expel air bubbles. It is then cooled and cured to form a laminated assembly with extremely high mechanical strength, using the film as an adhesive to completely seal and protect the power generation layer. This laminated assembly is a robust, sealed, and weather-resistant whole, which can be stored or transported long distances as a stable semi-finished product.

[0048] This invention successfully decouples battery chip manufacturing from subsequent customized processes by producing stable, robust, and easily transportable "standardized laminated semi-finished products," making off-site and near-customer processing possible, thereby optimizing the supply chain layout, reducing overall costs, and rapidly responding to market demands.

[0049] S60 Cut: Cutting the laminated components.

[0050] The laminated components are cut into individual components of customized sizes and shapes according to customer requirements. For example, the laminated components are fixed on a CNC cutting platform, the customer's customized size and shape parameters or customer drawings are input, and the cutting head is controlled to precisely cut the laminated components.

[0051] In the S60 cutting process, the object being cut is a robust, sealed, and weather-resistant monolaminated module, not just the fragile, exposed power generation layer. The power generation layer is always protected between the substrate and the backsheet, so debris and impurities generated during cutting do not adhere to it. Because the power generation layer is supported on both sides by the substrate and backsheet, the cutting head is less likely to cause microcracks or damage during cutting. After cutting, when disassembling individual modules, the power generation layer is also less likely to develop microcracks or damage due to the support of the substrate and backsheet on both sides.

[0052] CNC cutting platforms can perform precision cutting of laminated components using methods such as water jet cutting, laser cutting, and mechanical cutting.

[0053] Waterjet cutting uses ultra-high pressure water jets (mixed with abrasives such as garnet sand) for cutting. Its advantages include cold cutting, no thermal stress, no damage to the performance of the power generation layer, high cut quality, avoidance of subsequent edge grinding, further reducing potential impact on the power generation layer, and applicability to any shape.

[0054] Laser cutting uses a high-power laser beam to scan and cut, which is fast and precise.

[0055] Mechanical cutting uses diamond grinding wheels or dicing wheels for cutting, which is less expensive.

[0056] As an optional implementation, an edge grinding step S61 can also be performed after the S60 cutting step.

[0057] S61 Edge Grinding: Using a CNC edge grinding machine equipped with grinding wheels of different grit sizes, the edges of the cut laminated components are chamfered and smoothed. This removes burrs, beautifies the cut edges, and improves safety and aesthetics. The dust generated in this step exists only at the edges of the laminated components, and since the power generation layer is firmly encapsulated by the post-encapsulation film and sealant, it cannot contaminate the power generation layer.

[0058] S70 test: Install the junction box on the cut laminated assembly and connect it to the busbar, then perform the test.

[0059] The S70 testing procedure completes the final electrical connections and final product inspection of the laminated assembly.

[0060] The junction box can be installed and connected to the busbar by adhesive or welding to discharge the current drawn from the busbar. Then, standard electrical performance tests are performed, including voltage and current tests, to verify that the power output is up to standard.

[0061] Once qualified, the products can be packaged according to specifications.

[0062] The method described in this invention has the following significant advantages over the existing "cut-then-laminate" process: 1. By placing the cutting step after the lamination step, the fragile power generation layer is protected and supported by the substrate and backplate from the very beginning of processing. This fundamentally eliminates the contamination and physical damage to the power generation layer caused by subsequent processes. It also prevents the power generation layer from being exposed to the external environment during the cutting process, thus fundamentally solving the technical problems of the power generation layer being easily contaminated during cutting and easily damaged by mechanical cutting, thereby improving product yield and long-term reliability.

[0063] By placing the cutting step after the lamination step and performing it in a concentrated manner, it can efficiently and accurately meet the order requirements of various sizes and shapes. It is particularly suitable for the needs of irregular products (including different sizes) in Building Integrated Photovoltaic (BIPV) applications, achieving efficient, high-quality, and low-cost production. It solves the technical problem that traditional processes cannot meet the needs of irregular products in BIPV, and is especially suitable for small-batch, diversified customized production modes.

[0064] 2. The existing "cut-then-laminate" process requires handling battery chips of various sizes, and the lamination and assembly processes are difficult to automate, resulting in low production efficiency and high labor costs.

[0065] This invention integrates and laminates the components of a thin-film solar cell in a standard large-area whole-cell size, enabling the core processes (assembly and lamination) to handle uniform large-area whole-cell sizes. This allows it to be adapted to efficient and continuous automated production lines, overcoming the problems of production interruptions, low efficiency, and high costs caused by orders for multiple sizes and irregular shapes. It also solves the technical problem of automating the assembly and lamination processes.

[0066] 3. In the existing "cut-then-laminate" process, the cut battery chips are difficult to store and transport because their surfaces are easily contaminated and their structures are fragile. They must be produced locally, and the battery chips and packaging are integrated, which limits the scale of production and the speed of market response.

[0067] The thin-film solar cell products prepared by the method described in this invention have a stable structure and are not easily contaminated. This solves the technical problem of storage and transportation difficulties that necessitate localized production, and supports standardized and streamlined production processes as well as off-site processing.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, various improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a thin-film solar cell, characterized in that, Includes the following steps: A power generation layer is fabricated on a substrate to obtain a battery chip; Remove a certain width from the edge of the power generation layer; Lead the busbars from the power generation layer; On the side of the power generation layer away from the substrate, the encapsulating film and the backplate are placed sequentially and aligned to obtain a stacked module; The laminated components are laminated to obtain a laminated component; Cut the laminated components; Install a junction box on the cut laminated assembly and connect it to the busbar, then test it.

2. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: The pre-encapsulation film and cover plate are placed sequentially and aligned on the side of the substrate away from the power generation layer to obtain the stacked assembly.

3. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: After removing a certain width of the edge of the power generation layer, a sealant is applied to the substrate around the perimeter of the power generation layer.

4. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: After cutting the laminated components, the edges of the cut laminated components are ground.

5. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: The power generation layer includes a conductive layer, a window layer, an absorption layer, a back contact layer, and a back electrode arranged in sequence.

6. The method for preparing a thin-film solar cell as described in claim 5, characterized in that: The conductive layer is a fluorine-doped tin oxide layer; The window layer is a cadmium sulfide layer or a cadmium selenide layer; The absorber layer is a cadmium telluride layer; The back contact layer is a zinc telluride layer; The back electrode is a molybdenum layer.

7. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: A power generation layer is prepared on a substrate using a vacuum deposition process, and then a single-junction or multi-junction battery chip is formed by laser etching of the power generation layer.

8. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: The laser travels along a planned path along the edge of the power generation layer to remove a certain width of the edge.

9. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: Laminated components are obtained by laminating stacked components under vacuum and heating conditions.

10. The method for preparing a thin-film solar cell as described in claim 1, characterized in that: Laminated components are cut using water jet cutting, laser cutting, or mechanical cutting.

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