A large-area CdTe solar cell assembly and a manufacturing method thereof

Abstract

The present invention provides a large-area CdTe solar cell module and a manufacturing method thereof, comprising: providing a transparent flexible substrate coated with an aluminum film, etching the aluminum film into bottom electrode circuits of multiple units through a roll-to-roll etching process, wherein the bottom electrode circuit of each unit includes an edge main grid line and an internal fine grid line; forming multiple through holes, depositing a conductive material in the through holes to form a back electrode; depositing a transparent oxide bottom electrode layer, a window layer, a buffer layer, a CdTe light absorption layer, a back contact layer and a front electrode layer; printing a top electrode grid line; cutting into multiple separated CdTe solar cell units; and bonding with a conductive adhesive to form a CdTe solar cell module in series. The aluminum film and bottom electrode circuit process of the present invention is suitable for continuous production in a roll-to-roll manner, and then a flexible component is formed by cutting and stacking. The shape and size of the single cell can be designed through the etching circuit, and the component area and shape design are highly flexible, and zero "dead zone" can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic cells, and in particular relates to a large-area CdTe solar cell assembly and a manufacturing method thereof. Background Art

[0002] Thin-film solar cells have a place in the field of solar cells due to their advantages such as low cost and weak light effect, and have developed rapidly in recent years. Since CdTe has a high absorption coefficient and an optimal energy gap suitable for solar energy conversion, CdTe has attracted widespread attention and attention as an important photoelectric conversion material in the photovoltaic field. The absorption spectrum of cadmium telluride is very consistent with the solar spectrum, and it can absorb more than 95% of sunlight. It can form a CdS / CdTe heterojunction with CdS (~2.42eV) with a wide energy gap. CdTe solar cells are thin-film solar cells based on the CdS / CdTe heterojunction, with a theoretical conversion efficiency of nearly 30%. Compared with single-crystal silicon solar cells, they have the advantages of easy production, low cost and light weight. At present, the efficiency of small-area cells in the laboratory has exceeded 23%, and the efficiency of commercial components has reached 19%.

[0003] Currently, thin-film solar cells are mainly used in BIPV. Traditional flat-plate thin-film solar cells are solid-state rigid structures, the glass substrate is heavy, and the shape and area of ​​the components are difficult to change according to specific application scenarios, thus affecting the scope of their application.

[0004] Therefore, providing a new large-area CdTe solar cell assembly and a method for manufacturing the same is a problem that needs to be solved by those skilled in the art. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a large-area CdTe solar cell module and a method for manufacturing the same, so as to solve the problem in the prior art that the shape of the single solar cell and the area of ​​the module are difficult to change according to the specific application occasion.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a method for manufacturing a large-area CdTe solar cell module, the manufacturing method at least comprising:

[0007] 1) providing a transparent flexible substrate with an aluminum film on the surface, and etching the aluminum film to form bottom electrode circuits of multiple units through a roll-to-roll etching process, wherein the bottom electrode circuit of each unit includes an edge main grid line and an internal fine grid line electrically connected to the main grid line;

[0008] 2) forming a plurality of through holes in the transparent flexible substrate to expose the main grid lines, and depositing a conductive material in the through holes to form a back electrode;

[0009] 3) depositing a transparent oxide bottom electrode layer, a window layer, a buffer layer, a CdTe light absorption layer, a back contact layer and a front electrode layer covering the bottom electrode circuit on the surface of the transparent flexible substrate in sequence;

[0010] 4) printing the top electrode grid lines on the surface of the front electrode layer to form a whole roll of CdTe solar cells;

[0011] 5) cutting the whole roll of CdTe solar cells into a plurality of separate CdTe solar cell units according to the unit by die-cutting;

[0012] 6) Adhere the back electrode in each CdTe solar cell unit to the top electrode grid line in the next adjacent CdTe solar cell unit with conductive adhesive, thereby forming the CdTe solar cell module connected in series.

[0013] Optionally, the transparent flexible substrate is a polyimide substrate.

[0014] Optionally, the transparent oxide bottom electrode layer is one of ITO, FTO, and AZO, and is formed by a continuous magnetron sputtering method; the window layer is MgZnO or SnO2, and is formed by magnetron sputtering or chemical deposition, with a thickness between 40 and 70 nm.

[0015] Optionally, the buffer layer is CdS / CdSe, with a thickness between 50 and 100 nm, formed by vapor transport deposition; the CdTe light absorption layer has a thickness between 2.0 and 4.0 μm, is formed by vapor transport deposition and is activated by annealing with an activation liquid, the activation liquid is a cadmium chloride or magnesium chloride aqueous solution, the activation annealing temperature is 300 to 400°C, and the time is 5 to 10 minutes.

[0016] Optionally, the back contact layer is Cu-doped ZnTe with a thickness between 20 and 30 nm, and is formed by magnetron sputtering.

[0017] Optionally, the material of the front electrode layer includes PEDOT:PSS, which is formed by coating.

[0018] Optionally, the top electrode grid line is formed by screen printing a low-temperature curing paste, and the low-temperature curing conductive paste is one of conductive silver paste, conductive copper paste, conductive nickel paste, conductive silver-coated copper paste, conductive silver-coated nickel paste, and conductive gold paste.

[0019] Optionally, in step 6), the CdTe solar cell units fixed by bonding form an overlapping structure, and the total overlapping area is less than 2% of the total area of ​​the CdTe solar cell assembly.

[0020] Optionally, the conductive adhesive is a solvent-free thermal curing conductive adhesive, and the resistivity after curing is less than 10 -3 Ωcm.

[0021] The present invention also provides a large-area CdTe solar cell module manufactured by using any one of the above-mentioned methods for manufacturing a large-area CdTe solar cell module.

[0022] As described above, the large-area CdTe solar cell assembly and the method for manufacturing the same of the present invention have the following beneficial effects:

[0023] 1) The present invention adopts a roll-to-roll coating process and an etching process to form a bottom electrode circuit on a substrate. The roll-to-roll technology can be produced continuously, greatly improving the production efficiency of the battery and reducing the production cost.

[0024] 2) The substrate of the present invention is a transparent, lightweight and flexible substrate, which can be cut and stacked to form a flexible component. In addition, the shape and size of the single battery can be designed by etching the bottom electrode circuit. The design flexibility of the entire component area shape is higher, there is no dead area, and cutting is convenient, which is suitable for applications in various occasions. The component can receive light on both sides, giving full play to the advantages of good weak light performance and improving power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figures 1 to 9 The schematic diagram of the structure of each step of the method for making a large-area CdTe solar cell module of the present invention is shown in FIG. Fig. 9 It is a schematic diagram of a large-area CdTe solar cell assembly of the present invention.

[0026] Fig.10 It is an overall schematic diagram of the large-area CdTe solar cell assembly of the present invention.

[0027] Component number description

[0028] 1 Aluminum film

[0029] 2 Transparent flexible substrate

[0030] 3 Bottom electrode circuit

[0031] 31 Busbar

[0032] 32 fine lines

[0033] 4 Through holes

[0034] 5 Back electrode

[0035] 6 Transparent oxide bottom electrode layer

[0036] 7 Window Layer

[0037] 8 Buffer layer

[0038] 9 CdTe light absorption layer

[0039] 10 Back contact layer

[0040] 11 Front electrode layer

[0041] 12 Top electrode grid line

[0042] 13 Conductive adhesive

[0043] 100 CdTe solar cells DETAILED DESCRIPTION

[0044] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0045] Please refer to the attached drawings. It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0046] like Figures 1 to 9 As shown, the present invention provides a method for manufacturing a large-area CdTe solar cell module, and the manufacturing method at least comprises the following steps:

[0047] First, execute step 1), such as Figure 1 As shown, a transparent flexible substrate 2 with an aluminum film 1 on its surface is provided, such as Figure 2 As shown, the aluminum film 1 is etched by a roll-to-roll etching process to form bottom electrode circuits 3 of multiple units, and the bottom electrode circuit 3 of each unit includes an edge main grid line 31 and an internal fine grid line 32 electrically connected to the main grid line 31 .

[0048] As an example, the transparent flexible substrate 2 is a polyimide substrate. Of course, the transparent flexible substrate 2 can also be made of other suitable materials, which is not limited here.

[0049] The aluminum film 1 is formed on the transparent flexible substrate 2 by roll-to-roll coating, and the aluminum film 1 is etched by roll-to-roll etching. The roll-to-roll technology can achieve continuous production, greatly improve the production efficiency of the battery, and reduce the production cost.

[0050] The main grid lines 31 are located at the edge of each cell, and the fine grid lines 32 are located inside each cell. The main grid lines 31 and the fine grid lines 32 in the cell are electrically connected, and the bottom electrode lines 3 of adjacent cells are not electrically connected.

[0051] The position, shape and size of the main grid line 31 at the edge can define the area and shape of each solar cell unit, for example, it can be a square, a circle or relatively parallel lines. In this embodiment, the shape of the main grid line 31 is a group of relatively parallel lines, which is more convenient for subsequent cutting. The arrangement of the fine grid lines 32 is not limited, for example, it can be arranged in parallel, or arranged radially with the midpoint as the center, etc., which is not limited here. The fine grid lines 32 are used to collect photocurrent, and the collected photocurrent is collected to the main grid lines 31.

[0052] Then execute step 2), such as Figure 3 As shown, a plurality of through holes 4 exposing the main grid lines 31 are formed in the transparent flexible substrate 2. Figure 4 As shown, a conductive material is deposited in the through hole 4 to form a back electrode 5.

[0053] As an example, a laser may be used to punch holes in the transparent flexible substrate 2 to form a plurality of continuously distributed through holes 4, and the shapes of the through holes 4 are set according to specific requirements, including but not limited to circular, square, triangular, etc. The positions of the through holes 4 correspond to the positions of the main grid lines 31. The conductive material deposited in the through holes 4 forms an electrical connection with the main grid lines 31.

[0054] As an example, the conductive material includes but is not limited to a combination of one or more of silver, aluminum, gold, copper and nickel. In this embodiment, the conductive material is electroplated copper.

[0055] Then execute step 3), such as Figure 5 As shown, a transparent oxide bottom electrode layer 6 covering the bottom electrode circuit 3 , a window layer 7 , a buffer layer 8 , a CdTe light absorption layer 9 , a back contact layer 10 and a front electrode layer 11 are sequentially deposited on the surface of the transparent flexible substrate 2 .

[0056] As an example, the transparent oxide bottom electrode layer 6 is one of ITO, FTO, and AZO, and is formed by continuous magnetron sputtering; the window layer 7 is MgZnO or SnO2, and is formed by magnetron sputtering or chemical deposition, and has a thickness between 40 and 70 nm. In this embodiment, the transparent oxide bottom electrode layer 6 is ITO, the window layer is MgZnO, and the thickness of the window layer 7 is 50 nm.

[0057] As an example, the buffer layer 8 is CdS / CdSe, with a thickness between 50 and 100 nm, formed by vapor transport deposition; the CdTe light absorption layer 9 has a thickness between 2.0 and 4.0 μm, formed by vapor transport deposition and activated by an activation liquid for annealing, the activation liquid is a cadmium chloride or magnesium chloride aqueous solution, the activation annealing temperature is 300 to 400°C, and the time is 5 to 10 minutes. In this embodiment, the thickness of the buffer layer 8 is 80 nm, and the thickness of the CdTe light absorption layer 9 is 3.0 μm.

[0058] As an example, the back contact layer 10 is Cu-doped ZnTe, has a thickness between 20 and 30 nm, and is formed by magnetron sputtering. In this embodiment, the thickness of the back contact layer 10 is 280 nm.

[0059] As an example, the material of the front electrode layer 11 includes PEDOT:PSS, which is formed by coating.

[0060] Then execute step 4), such as Figure 6 As shown, the top electrode grid line 12 is printed on the surface of the front electrode layer 11 to form a whole roll of CdTe solar cells.

[0061] As an example, the top electrode grid line 12 is formed by screen printing a low-temperature curing paste, and the low-temperature curing conductive paste is one of conductive silver paste, conductive copper paste, conductive nickel paste, conductive silver-coated copper paste, conductive silver-coated nickel paste, and conductive gold paste. In this embodiment, the low-temperature curing conductive paste is conductive silver paste.

[0062] Then execute step 5), such as Figure 7 and Figure 8 As shown, the whole roll of CdTe solar cells is cut into a plurality of separate CdTe solar cell units 100 by unit by die cutting.

[0063] In this step, follow the Figure 7 The entire roll of CdTe solar cells can be cut into a plurality of separate CdTe solar cell units 100 by cutting the dotted line portion shown in the figure. Figure 8 .

[0064] Based on the flexible characteristics of the components, the present invention adopts a die-cutting method to cut the CdTe solar cells, which is simple and convenient to operate and suitable for large-scale production.

[0065] Finally, execute step 6), such as Fig. 9As shown, the back electrode 5 in each CdTe solar cell unit 100 is bonded and fixed to the top electrode grid line 12 in the next adjacent CdTe solar cell unit 100 by using a conductive adhesive 13, thereby forming the CdTe solar cell module connected in series.

[0066] The CdTe solar cell units 100 are stacked to form an overlapping structure. Under the premise of ensuring the bonding strength, the overlapping area of ​​the overlapping structure should be as small as possible to achieve no dead zone. As an example, in this step, the CdTe solar cell units 100 fixed by bonding form an overlapping structure, and the total overlapping area is less than 2% of the total area of ​​the CdTe solar cell module.

[0067] like Fig.10 It is a schematic diagram of the whole assembly, and it can be clearly seen that the CdTe solar cell assembly with an overlapping structure is formed by connecting CdTe solar cell units 100 in series.

[0068] As an example, the conductive adhesive 13 is a solvent-free thermal curing conductive adhesive, and the resistivity after curing is less than 10 -3 Ωcm.

[0069] This embodiment also provides a large-area CdTe solar cell module manufactured using any of the above-mentioned methods for manufacturing a large-area CdTe solar cell module.

[0070] In summary, the present invention provides a large-area CdTe solar cell module and a manufacturing method thereof, including: 1) providing a transparent flexible substrate coated with an aluminum film, etching the aluminum film into multiple bottom electrode circuits of each unit through a roll-to-roll etching process, and the bottom electrode circuit of each unit includes an edge main grid line and an internal fine grid line; 2) forming multiple through holes, depositing a conductive material in the through holes to form a back electrode; 3) sequentially depositing a transparent oxide bottom electrode layer, a window layer, a buffer layer, a CdTe light absorption layer, a back contact layer and a front electrode layer; 4) printing a top electrode grid line; 5) cutting into multiple separated CdTe solar cell units; 6) using a conductive adhesive to form a series CdTe solar cell module. The present invention adopts a roll-to-roll coating process and an etching process to form a bottom electrode circuit on a substrate. The roll-to-roll technology can be produced continuously, greatly improving the production efficiency of the battery and reducing the production cost. Since the substrate is a transparent flexible substrate, a flexible component can be formed by cutting and stacking. In addition, the shape and size of the single battery can be designed by etching the bottom electrode line. In this way, the entire component is a flexible and lightweight structure with higher flexibility in design of area and shape, no dead zone and easy cutting, which is suitable for applications in various occasions.

[0071] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a large-area CdTe solar cell module, characterized in that: The production method at least comprises: 1) providing a transparent flexible substrate with an aluminum film on the surface, and etching the aluminum film to form bottom electrode circuits of multiple units through a roll-to-roll etching process, wherein the bottom electrode circuit of each unit includes an edge main grid line and an internal fine grid line electrically connected to the main grid line; 2) forming a plurality of through holes in the transparent flexible substrate to expose the main grid lines, and depositing a conductive material in the through holes to form a back electrode; 3) depositing a transparent oxide bottom electrode layer, a window layer, a buffer layer, a CdTe light absorption layer, a back contact layer and a front electrode layer covering the bottom electrode circuit on the surface of the transparent flexible substrate in sequence; 4) printing the top electrode grid lines on the surface of the front electrode layer to form a whole roll of CdTe solar cells; 5) cutting the whole roll of CdTe solar cells into a plurality of separate CdTe solar cell units according to the unit by die-cutting; 6) Adhere the back electrode in each CdTe solar cell unit to the top electrode grid line in the next adjacent CdTe solar cell unit with conductive adhesive, thereby forming the CdTe solar cell module connected in series.

2. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The transparent flexible substrate is a polyimide substrate.

3. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The transparent oxide bottom electrode layer is one of ITO, FTO, and AZO, and is formed by a continuous magnetron sputtering method; the window layer is MgZnO or SnO2, and is formed by magnetron sputtering or chemical deposition, with a thickness between 40 and 70 nm.

4. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The buffer layer is CdS / CdSe, with a thickness between 50 and 100 nm, formed by vapor transport deposition; the CdTe light absorption layer has a thickness between 2.0 and 4.0 μm, is formed by vapor transport deposition and is activated by annealing with an activation liquid, the activation liquid is a cadmium chloride or magnesium chloride aqueous solution, the activation annealing temperature is 300 to 400° C., and the time is 5 to 10 minutes.

5. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The back contact layer is Cu-doped ZnTe with a thickness between 20 and 30 nm, and is formed by magnetron sputtering.

6. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The material of the front electrode layer includes PEDOT:PSS and is formed by coating.

7. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The top electrode grid line is formed by screen printing a low-temperature curing paste, and the low-temperature curing conductive paste is one of conductive silver paste, conductive copper paste, conductive nickel paste, conductive silver-coated copper paste, conductive silver-coated nickel paste, and conductive gold paste.

8. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: In step 6), the CdTe solar cell units fixed by bonding form an overlapping structure, and the total overlapping area is less than 2% of the total area of ​​the CdTe solar cell assembly.

9. The method for manufacturing a large-area CdTe solar cell assembly according to claim 1, characterized in that: The conductive adhesive is a solvent-free thermal curing conductive adhesive, and the resistivity after curing is less than 10 -3 Ωcm.

10. A large-area CdTe solar cell module manufactured by the method for manufacturing a large-area CdTe solar cell module according to any one of claims 1 to 9.

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