Thin-film solar cell and edge cleaning method thereof

Abstract

The present application relates to the field of thin-film solar cell modules, and provides a thin-film solar cell and a method for cleaning its edges. The method mainly avoids peeling and curling of the film layer by first covering the pre-planned cleaning area with an insulating isolation tape and laser etching an insulating area along the junction of the insulating isolation tape and the film layer. At the same time, it can also ensure that no film particles remain in the cleaning area. In addition, a thin-film solar cell prepared by the above method is provided, and this thin-film solar cell has excellent insulation properties.

Description

Technical Field

[0001] The present application relates to the field of thin-film solar cell components, and in particular to a thin-film solar cell and an edge cleaning method thereof. Background Art

[0002] With the increasing depletion of energy sources such as coal, oil, and natural gas, and the worsening environmental pollution, there is an urgent need to find clean, renewable energy sources. Solar energy, as an infinitely renewable, pollution-free energy source, is attracting increasing attention, and the development of solar cells that convert solar energy into electricity has rapidly advanced. Currently, commercially available crystalline silicon solar cells offer the highest photoelectric conversion efficiency, but limitations in material purity and manufacturing processes make further improvements in efficiency and cost reduction difficult. Thin-film solar cells, capable of achieving photoelectric conversion with a thickness of only a few microns, offer an ideal material for reducing costs and improving photon recycling.

[0003] In the preparation process of thin-film solar cells, after the film preparation is completed, the edge of the film layer needs to be scribed and insulated. By removing all the film layers in the edge cleaning area, it is ensured that each sub-cell in the subsequent process will not be short-circuited. There are currently three main edge cleaning processes, namely laser edge cleaning, sandblasting edge cleaning and grinding wheel edge cleaning. Among them, the working mode of laser edge cleaning is to remove the film layer around the thin-film solar cell through infrared or ultraviolet laser. Obviously, the power of the laser is an important parameter affecting the edge cleaning area. In actual work, if the power is too large, it will cause the edge of the film layer to produce burnt edges and the surface film layer to peel off, which will cause defects such as curling of the film edge, burrs, craters, etc., and there will be residual film particles in the edge cleaning area, resulting in poor insulation effect and easy leakage during use.

[0004] CN201110370809.X discloses a method for insulating thin-film solar cells. During the cell processing, the coating is removed from the first to the outermost layer of the glass coating by laminating and removing the covering material in the areas where the edges need to be cleaned between the different coating layers, thereby achieving cell insulation. The specific implementation method is described in paragraph

[0024] of the specification as follows: "Insulating tape is applied to the areas around the glass surface to be treated where the edges need to be cleaned. A front electrode is deposited to form conductive glass. After laser and cleaning processes, the conductive glass enters the coating equipment for absorption layer deposition. After laser etching, the back electrode is formed. After a third laser process, the insulating tape is finally removed, removing all film layers at the edge of the thin-film solar cell, including the front electrode, absorption layer, and back electrode. After cleaning, the insulation treatment of the cell is completed."

[0005] The above patent uses insulating tape to cover the edge-clearing area to prevent the film layer from being deposited on the edge-clearing area, and finally removes the insulating tape. Although the above patent can form a clear and clean edge-clearing area, its method of directly tearing off the insulating tape will cause the film layer to peel off, making it difficult to ensure the clarity of the film layer edge.

[0006] Based on this, the technical problem solved in this case is: how to solve the problem of defects at the edge of the film layer caused by the edge cleaning process of thin-film solar cells and the problem of residual film particles in the edge cleaning area. Summary of the Invention

[0007] In order to solve the above technical problems, the present application provides a method for cleaning the edges of thin-film solar cells. This method can avoid film peeling and curling by cutting the film layer through laser etching of the insulating area. At the same time, this method can also ensure that there are no film layer particles remaining in the cleaning area. A thin-film solar cell prepared by the above method is also provided, and this thin-film solar cell has excellent insulation properties.

[0008] The technical solution of this application is:

[0009] A method for cleaning edges of thin-film solar cells comprises the following steps in sequence:

[0010] Step 1: Plan the edge-clearing area and film layer area of the glass substrate, and cover the edge-clearing area with an insulating isolation tape;

[0011] Step 2: Depositing a film layer of a solar cell on the film layer area;

[0012] Step 3: At the junction of the insulating isolation tape and the film layer, an insulating region extending from the film layer to the glass substrate is etched using a laser with a power not exceeding 20W to isolate the film layer and the insulating isolation tape;

[0013] Step 4: Remove the insulating tape.

[0014] This application prevents the film layer from being deposited in the clean-edge area by covering the clean-edge area of the glass substrate with an insulating isolation tape, and then uses a low-power laser to etch the junction between the film layer and the insulating isolation tape. The purpose is to separate the film layer in advance to avoid the subsequent removal of the insulating isolation tape causing the film layer to separate. In addition, the use of low-power laser etching can make the edge of the film layer clearer than traditional high-power clean-edge methods.

[0015] In the above-mentioned method for edge cleaning of thin-film solar cells, in step 3, the power of the laser is 1 to 20 W, including but not limited to 1 W, 2 W, 3 W, 4 W, 5 W, 6 W, 7 W, 8 W, 9 W, 10 W, 11 W, 12 W, 13 W, 14 W, 15 W, 16 W, 17 W, 18 W, 19 W, and 20 W.

[0016] In the above-mentioned thin-film solar cell edge cleaning method, in step 3, the width of the insulating area is 20 to 30 μm, including but not limited to 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and 30 μm.

[0017] In the above-mentioned method for edge cleaning of a thin-film solar cell, when the thin-film solar cell is a perovskite solar cell, step 2 includes the following steps:

[0018] Step 21: depositing a bottom electrode layer on the glass substrate and performing a first laser scribing to form a plurality of P1 lines extending from the bottom electrode layer to the glass substrate;

[0019] Step 22: depositing an intermediate film layer on the bottom electrode layer and performing a second laser scribing to form a plurality of P2 lines extending from the intermediate film layer to the bottom electrode layer;

[0020] Step 23: Deposit a top electrode layer on the intermediate film layer and perform a third laser scribing to form a plurality of P3 lines extending from the top electrode layer to the bottom electrode layer, thereby dividing the plurality of sub-cells.

[0021] When the thin film solar cell is a cadmium telluride solar cell, step 2 includes the following steps:

[0022] Step 21: depositing a bottom electrode layer on the glass substrate;

[0023] Step 22: Depositing an intermediate film layer on the bottom electrode layer, performing a first laser scribing to form a plurality of P1 lines extending from the bottom electrode layer to the glass substrate; then performing a second laser scribing to form a plurality of P2 lines extending from the intermediate film layer to the bottom electrode layer;

[0024] Step 23: Deposit a top electrode layer on the intermediate film layer and perform a third laser scribing to form a plurality of P3 lines extending from the top electrode layer to the bottom electrode layer, thereby dividing the plurality of sub-cells.

[0025] In the above-mentioned thin-film solar cell edge cleaning method, in step 21, the deposition method used is any one of PVD and CVD, in step 22, the deposition method used is any one of PVD, VTD, and CSS, and in step 23, the deposition method used is PVD.

[0026] In the technical solution of the present invention, the P1 line, the P2 line, and the P3 line are commonly defined by those skilled in the art and can be obtained through existing technologies, so they will not be described in detail here; for example, the P1 line, the P2 line, and the P3 line disclosed in the patent publication number CN113257928A.

[0027] In the above-mentioned thin-film solar cell edge cleaning method, the insulating isolation tape is an insulating adhesive tape.

[0028] In the above-mentioned thin-film solar cell edge cleaning method, step 4 uses a scraper to remove the insulating isolation tape.

[0029] Also disclosed is a thin-film solar cell, which is manufactured by using any of the above-mentioned thin-film solar cell edge cleaning methods.

[0030] One of the above technical solutions of this application has at least one of the following advantages or beneficial effects:

[0031] The edge cleaning method of the present application prevents the subsequent deposited film layer from being contaminated on the glass substrate by first covering the pre-planned edge cleaning area with an insulating isolation tape. Compared with the traditional method, the present application can ensure that there are no film layer particles remaining in the edge cleaning area, thereby improving the insulation effect; at the same time, before removing the insulating isolation tape, the present application uses laser etching to form an insulating area along the junction of the insulating isolation tape and the film layer. This process can not only modify the edge of the film layer, but also prevent the edge of the film layer from being damaged during the removal of the insulating isolation tape, and even cause the film layer to peel off.

[0032] The thin-film solar cell prepared by the edge cleaning method of the present application has the characteristic of excellent insulation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A top view of the lamination edge cleaning of Example 1 of the present application;

[0034] Figure 2 This is a cross-sectional view of the lamination edge cleaning of Example 1 of the present application;

[0035] Figure 3 This is a rendering of the film edge of Example 2 of the present application;

[0036] Figure 4 This is a rendering of the film edge of Comparative Example 1 of the present application;

[0037] Figure 5 This is the effect diagram of the edge cleaning area of comparative example 4 of this application.

[0038] Wherein, the reference numerals are respectively:

[0039] 1. Glass substrate; 2. Bottom electrode layer; 3. Intermediate film layer; 4. Top electrode layer; A. Clear edge area; B. Insulating area; C. Film layer area. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0041] In the technical solution of the present invention, the P1 line, the P2 line, and the P3 line are commonly defined by those skilled in the art and can be obtained through existing technologies. Therefore, they are not described in detail in the following embodiments and comparative examples; for example, the P1 line, the P2 line, and the P3 line disclosed in the patent publication number CN113257928A.

[0042] Example 1

[0043] A method for cleaning edges of thin-film solar cells comprises the following steps in sequence:

[0044] Step 1: Plan the edge-clearing area A and the film layer area C of the glass substrate 1, and cover the edge-clearing area A with a layer of insulating tape;

[0045] Step 2: Depositing a film layer of a solar cell on the film layer area C;

[0046] Specifically, step 2 of this embodiment includes the following steps:

[0047] Step 21: Depositing a 500 nm thick layer of indium tin oxide as the bottom electrode layer 2 on the glass substrate 1 by PVD, and performing a first laser scribing to form a plurality of P1 lines extending from the bottom electrode layer 2 to the glass substrate 1;

[0048] Step 22: A nickel oxide layer with a thickness of 1 μm and a perovskite layer are sequentially coated on the bottom electrode layer 2, and a PCBM layer is deposited by PVD to form an intermediate film layer 3. A second laser scribing is performed to form a plurality of P2 lines extending from the intermediate film layer 3 to the bottom electrode layer 2;

[0049] Step 23: Deposit a 500 nm thick TCO thin film as the top electrode layer 4 on the intermediate film layer 3 by PVD, and perform a third laser scribing to form multiple P3 lines extending from the top electrode layer 4 to the bottom electrode layer 2, thereby dividing multiple sub-cells.

[0050] It should be noted that the laser power for etching the P1 line, P2 line, and P3 line is 10W.

[0051] Step 3: Using a 10W laser, an insulating region B is etched at the junction of the insulating isolation tape and the film layer, extending from the film layer to the glass substrate 1, to isolate the film layer and the insulating isolation tape. In this embodiment, the width of the insulating region B is 20 μm.

[0052] Step 4: Use a scraper to remove the insulating tape.

[0053] Example 2

[0054] The process is basically the same as that of Example 1, except that in step 3, a 5W laser power is used to etch the insulating region B.

[0055] Example 3

[0056] The process is basically the same as that of Example 1, except that in step 3, a 3W laser power is used to etch the insulating region B.

[0057] Example 4

[0058] The process is basically the same as that of Example 1, except that in step 3, a 20W laser power is used to etch the insulating region B.

[0059] Example 5

[0060] A method for cleaning edges of thin-film solar cells comprises the following steps in sequence:

[0061] Step 1: Plan the edge-clearing area A and the film layer area C of the glass substrate 1, and cover the edge-clearing area A with a layer of insulating tape;

[0062] Step 2: Depositing a film layer of a solar cell on the film layer area C;

[0063] Specifically, step 2 of this embodiment includes the following steps:

[0064] Step 21: depositing a layer of indium tin oxide with a thickness of 500 nm as the bottom electrode layer 2 on the glass substrate 1 by PVD;

[0065] Step 22: On the bottom electrode layer 2, a 1 μm thick CdS film and a CdTe film are sequentially deposited using VTD, and a 40 nm thick ZnTe film is deposited using PVD to form the intermediate film layer 3. A first laser scribing is performed to form a plurality of P1 lines extending from the bottom electrode layer 2 to the glass substrate 1. Then, the P1 scribe grooves are filled with photoresist and exposed to light to prevent the film layer 4 from penetrating and causing short circuits between sub-cells. A second laser scribing is performed to form a plurality of P2 lines extending from the intermediate film layer 3 to the bottom electrode layer 2.

[0066] Step 23: Deposit a 500nm thick layer of Cu, Al or other metal material on the intermediate film layer 3 by PVD as the top electrode layer 4, and perform a third laser scribing to form multiple P3 lines extending from the top electrode layer 4 to the bottom electrode layer 2, thereby dividing multiple sub-cells.

[0067] Step 3: Using a 10W laser to etch an insulating region B extending from the film layer to the glass substrate 1 at the junction of the insulating isolation tape and the film layer, the insulating region B is used to isolate the film layer and the insulating isolation tape. In this embodiment, the line width of the insulating region B is 30 μm.

[0068] In order to maximize the effective utilization rate of the battery and avoid removing the effective power generation area formed by the P1 line and the P3 line when laser etching the insulating area B, in this embodiment, the insulating area B is set on the edge of the dead zone formed by the P1 line and the P3 line, that is, the junction of the insulating isolation zone and the film layer is the dead zone.

[0069] Step 4: Use a scraper to remove the insulating tape.

[0070] Example 6

[0071] It is basically the same as Example 5, except that in step 3, a 5W power laser is used to etch the insulating area B.

[0072] Example 7

[0073] It is basically the same as Example 5, except that in step 3, a 3W power laser is used to etch the insulating area B.

[0074] Example 8

[0075] It is basically the same as Example 5, except that in step 3, a 20W power laser is used to etch the insulating area B.

[0076] Comparative Example 1

[0077] The process is basically the same as that of Example 1, except that in step 3, a 30W laser power is used to etch the insulating region B.

[0078] Comparative Example 2

[0079] The method is basically the same as Example 1, except that in step 3, a 500W laser power is used to etch the insulating area B.

[0080] Comparative Example 3

[0081] The method is basically the same as Example 1, except that in step 3, a 1000W power laser is used to etch the insulating area B.

[0082] Comparative Example 4

[0083] A layer of indium tin oxide with a thickness of 500 nm is deposited on the glass substrate 1 by PVD as the bottom electrode layer 2, and a first laser scribing is performed to form a plurality of P1 lines extending from the bottom electrode layer 2 to the glass substrate 1;

[0084] A nickel oxide layer and a perovskite layer with a thickness of 1 μm are sequentially coated on the bottom electrode layer 2, and PCBM is deposited by PVD to form an intermediate film layer 3. A second laser scribing is performed to form multiple P2 lines extending from the intermediate film layer 3 to the bottom electrode layer 2.

[0085] A 500 nm thick TCO thin film is deposited on the intermediate film layer 3 by PVD as the top electrode layer 4. A third laser scribing is performed to form multiple P3 lines extending from the top electrode layer 4 to the bottom electrode layer 2, thereby dividing multiple sub-cells.

[0086] Finally, a 1000W power laser is used to complete the edge cleaning process.

[0087] Test: The methods of Examples 1 to 8 and Comparative Examples 1 to 4 were used to prepare corresponding solar thin-film batteries and perform a 3600V insulation withstand voltage test.

[0088] Table 1: Edge states and test leakage current values of solar thin film cells prepared in Examples 1 to 8 and Comparative Examples 1 to 4

[0089]

[0090]

[0091] Result analysis:

[0092] Combine Figures 3 to 5 In practical applications, Examples 1 to 8 can all achieve the effect of smoothing the edge of the film layer, among which the edge of the film layer of Example 2 is the smoothest. Figure 3 .

[0093] Figure 4 The edge of the film layer of comparative example 1 is obviously affected by heat, which is manifested as the top electrode layer 4 rolling up. Similarly, the edges of the film layers of comparative examples 2 and 3 also show obvious heat effects, and the edge of the film layer of comparative example 3 is seriously burnt. Figure 5 In comparative example 4, a large amount of film particles remain in the edge cleaning area A, and the film particles are electrostatically adsorbed on the glass substrate and are difficult to remove, which can easily cause poor insulation between the sub-cells or even short circuits.

[0094] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for cleaning the edge of a thin-film solar cell, characterized in that: The following steps are included in sequence: Step 1: Plan the edge-clearing area and film layer area of the glass substrate, and cover the edge-clearing area with an insulating isolation tape; Step 2: Depositing a film layer of a solar cell on the film layer area; Step 3: Use a 1-20W laser to etch an insulating region extending from the film layer to the glass substrate at the junction of the insulating isolation tape and the film layer to isolate the film layer and the insulating isolation tape; Step 4: Remove the insulating tape.

2. The thin-film solar cell edge cleaning method according to claim 1, characterized in that: In step 3, the width of the insulating region is 20-30 μm.

3. The thin-film solar cell edge cleaning method according to claim 1, characterized in that: The step 2 comprises the following steps: Step 21: depositing a bottom electrode layer on the glass substrate and performing a first laser scribing to form a plurality of P1 lines extending from the bottom electrode layer to the glass substrate; Step 22: depositing an intermediate film layer on the bottom electrode layer and performing a second laser scribing to form a plurality of P2 lines extending from the intermediate film layer to the bottom electrode layer; Step 23: Deposit a top electrode layer on the intermediate film layer and perform a third laser scribing to form a plurality of P3 lines extending from the top electrode layer to the bottom electrode layer, thereby dividing the plurality of sub-cells.

4. The thin-film solar cell edge cleaning method according to claim 3, characterized in that: In step 21, the deposition method used is any one of PVD and CVD. In step 22, the deposition method used is any one of PVD, VTD, and CSS. In step 23, the deposition method used is PVD.

5. The thin-film solar cell edge cleaning method according to claim 1, characterized in that: The insulating isolation tape is an insulating adhesive tape.

6. The thin-film solar cell edge cleaning method according to claim 1, characterized in that: In step 4, a scraper is used to remove the insulating isolation tape.

7. A thin film solar cell, characterized in that: The thin-film solar cell is manufactured by the edge cleaning method according to any one of claims 1 to 6.

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