Solar cell cutting edge passivation film layer structure and preparation method and application thereof

Abstract

The invention provides a solar cell cutting edge passive film layer structure and a preparation method and application thereof, and relates to the technical field of solar cells, and the solar cell cutting edge passive film layer structure comprises a tunneling layer, a polycrystalline silicon layer and an aluminum oxide film layer which are sequentially laminated on the cutting edge of a cut cell. According to the solar cell cutting edge passivation film layer structure, the composite film layer structure is adopted, the cutting edge passivation capability is improved, the SiO2 + polycrystalline silicon layer is adopted as the bottom layer structure, the Al2O3 film layer is adopted as the outer layer, the passivation capability of the edge passivation film layer is improved, and the module power is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell cut edge passivation film structure, a preparation method and an application thereof. Background Art

[0002] During the manufacturing process of solar cells, the cutting process inevitably introduces a large number of defect states at the edges of the cells. These defect states become active areas for carrier recombination, thereby affecting the overall efficiency of the cell. To suppress the adverse effects of these defects, the cut edges of the cell are usually passivated to reduce the surface recombination rate of carriers. However, the existing cutting passivation film layer is an Al2O3 film layer produced by atomic layer deposition of H2O and TMA on the cut surface of the cell. This film layer structure is a single Al2O3 film structure, which has insufficient edge passivation ability and the power gain of the component is not obvious.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] One of the objectives of the present invention is to provide a solar cell cut edge passivation film structure to at least solve one of the technical problems existing in the prior art. The present invention improves the passivation capability of the edge passivation film layer and can increase the module power.

[0005] A second object of the present invention is to provide a method for preparing a passivation film structure for cutting edges of solar cells.

[0006] A third object of the present invention is to provide a solar cell cut edge passivation film layer structure or the use of the solar cell cut edge passivation film layer structure prepared by the preparation method in the preparation of solar cell wafers.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: In a first aspect, the present invention provides a solar cell cut edge passivation film layer structure, comprising: a tunneling layer, a polysilicon layer and an aluminum oxide film layer stacked in sequence on the cut edge of the cut cell.

[0008] Furthermore, the thickness of the tunneling layer is 1-2.5 nm; Preferably, the material of the tunneling layer is silicon dioxide.

[0009] Furthermore, the thickness of the polysilicon layer is 10-50 nm; Preferably, the polysilicon layer includes a phosphorus-doped polysilicon layer or a boron-doped polysilicon layer.

[0010] Furthermore, the thickness of the aluminum oxide film layer is 8-30 nm.

[0011] In a second aspect, the present invention provides a method for preparing a passivation film structure at the cut edge of a solar cell, comprising: a tunneling layer, a polysilicon layer and an aluminum oxide film layer stacked in sequence at the cut edge of the cell after cutting.

[0012] Furthermore, the tunneling layer is prepared by a PECVD process; Preferably, the gas used to prepare the tunneling layer includes N2O; the gas flow rate of N2O is 5000-20000 sccm; the deposition time is 80-200 s; and the deposition temperature is 350-500°C.

[0013] Furthermore, the preparation process of the polysilicon layer includes: preparing an amorphous silicon layer by a PECVD process, and then performing an annealing to obtain the polysilicon layer; Preferably, the gases used to prepare the amorphous silicon layer include PH3, SiH4 and H2; the gas flow rate of PH3 is 8000-12000 sccm; the gas flow rate of SiH4 is 1000-5000 sccm; the gas flow rate of H2 is 1000-5000 sccm; the deposition time is 200-1000 s; and the deposition temperature is 350-500° C. Preferably, the temperature of the primary annealing is 800-1000° C.; and the time of the primary annealing is 20-100 min.

[0014] Furthermore, the aluminum oxide film layer is prepared by an atomic layer deposition process; Preferably, the gases used to prepare the aluminum oxide film layer include H2O and TMA; the gas flow ratio of H2O to TMA is 1-5:3-7; and the deposition temperature is 200-300°C.

[0015] Furthermore, a secondary annealing is performed after the tunneling layer, the polysilicon layer and the aluminum oxide film layer are formed; Preferably, the temperature of the secondary annealing is 200-400°C; Preferably, the secondary annealing time is 30-150 min.

[0016] In a third aspect, the present invention provides a solar cell cut edge passivation film layer structure or an application of the solar cell cut edge passivation film layer structure prepared by the preparation method in the preparation of solar cell wafers.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The solar cell cut edge passivation film layer structure provided by the present invention forms a multi-layer composite passivation structure by sequentially depositing a tunneling layer, a polysilicon layer, and an aluminum oxide film layer on the cut edge of the cell. The passivation film layer adopts a composite film layer structure, combining the passivation mechanisms of different materials: the tunneling layer provides good interface passivation, the polysilicon enhances the charge transfer capability, and the aluminum oxide film layer provides a strong electric field passivation effect. The solar cell cut edge passivation film layer structure provided by the present invention significantly improves the edge passivation capability, effectively reduces the carrier recombination caused by surface and interface defects, and can improve the conductivity of the cell edge area, thereby improving the overall component power; compared with a single Al2O3 passivation layer, the composite structure has a more comprehensive and stable passivation effect. DETAILED DESCRIPTION

[0018] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, the use of "or" means "and / or" unless otherwise stated. In addition, the use of the term "including" and other forms is non-limiting.

[0019] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] A first aspect of the present invention provides a solar cell cut edge passivation film layer structure, comprising: a tunneling layer, a polysilicon layer and an aluminum oxide film layer stacked in sequence on the cut edge of a cut cell.

[0021] In the present invention, the passivation film layer adopts a composite film structure to enhance the passivation capability of the cut edge. The bottom structure is a SiO2 + polysilicon layer prepared by PECVD deposition process, and the outer layer is an Al2O3 film layer prepared by atomic layer deposition. The SiO2 tunneling layer is located between the cut edge of the cell and the polysilicon layer. It serves as the first interface passivation layer and has good chemical stability, effectively passivating the dangling bonds on the silicon surface. The polysilicon layer is located above the SiO2 layer, forming an intermediate conductive and passivation layer. Together with the SiO2, it forms an interface state passivation layer, enhancing the overall structural stability of the passivation layer. The Al2O3 layer covers the polysilicon layer and serves as the outermost passivation protection layer. It forms an electric field-interface synergistic passivation with the internal SiO2 / polysilicon.

[0022] In some preferred embodiments, the thickness of the tunneling layer is 1-2.5 nm, for example, 1 nm, 1.5 nm, 2 nm, 2.5 nm, etc.; Preferably, the material of the tunneling layer is silicon dioxide.

[0023] In some preferred embodiments, the thickness of the polysilicon layer is 10-50 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc. Preferably, the polysilicon layer includes a phosphorus-doped polysilicon layer or a boron-doped polysilicon layer.

[0024] In some preferred embodiments, the thickness of the aluminum oxide film layer is 8-30 nm, for example, it can be 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, etc.

[0025] The second aspect of the present invention provides a method for preparing a passivation film structure at the cut edge of a solar cell, comprising: sequentially stacking a tunneling layer, a polysilicon layer, and an aluminum oxide film layer at the cut edge of a cut cell.

[0026] In some preferred embodiments, the tunneling layer is prepared by a PECVD process; Preferably, the gas used to prepare the tunneling layer includes N2O; the gas flow rate of N2O is 5000-20000sccm, for example, it can be 5000sccm, 10000sccm, 15000sccm, 20000sccm, etc.; the deposition time is 80-200s, for example, it can be 80s, 140s, 200s, etc.; the deposition temperature is 350-500℃, for example, it can be 300℃, 350℃, 400℃, 450℃, 500℃, etc.

[0027] In some preferred embodiments, the preparation process of the polysilicon layer includes: preparing an amorphous silicon layer by a PECVD process, and then performing an annealing to obtain the polysilicon layer; Preferably, the gases used to prepare the amorphous silicon layer include PH3, SiH4 and H2; the gas flow rate of PH3 is 8000-12000 sccm, for example, 8000 sccm, 10000 sccm, 12000 sccm, etc.; the gas flow rate of SiH4 is 1000-5000 sccm, for example, 1000 sccm, 2000 sccm, 3000 sccm, 4000 sccm, 5000 sccm, etc.; the gas flow rate of H2 is 1000-5000 sccm, for example, 1000 sccm, 2000 sccm, 3000 sccm, 4000 sccm, 5000 sccm, etc.; the deposition time is 200-1000 s, for example, 200 s, 600 s, 1000 s, etc.; the deposition temperature is 350-500°C, for example, 300°C, 350°C, 400°C, 450°C, 500°C, etc.; Preferably, the primary annealing temperature is 800-1000°C, for example, 800°C, 900°C, 1000°C, etc.; the primary annealing time is 20-100min, for example, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, etc.

[0028] In some preferred embodiments, the aluminum oxide film layer is prepared by an atomic layer deposition process; Preferably, the gases used to prepare the aluminum oxide film layer include H2O and TMA; the gas flow ratio of H2O and TMA is 1-5:3-7, where "1-5" can be, for example, 1, 2, 3, 4, 5, etc., and "3-7" can be, for example, 3, 4, 5, 6, 7, etc., preferably 3:4; the deposition temperature is 200-300°C, for example, 200°C, 250°C, 300°C, etc.

[0029] In some preferred embodiments, a secondary annealing is performed after forming the tunneling layer, the polysilicon layer and the aluminum oxide film layer; Preferably, the temperature of the secondary annealing is 200-400°C, for example, 200°C, 250°C, 300°C, 350°C, 400°C, etc.; Preferably, the secondary annealing time is 30-150 min, for example, 30 min, 90 min, 150 min, etc.

[0030] In this invention, a secondary annealing step after Al2O3 deposition improves interfacial stress, enhances interlayer bonding, and improves overall structural stability. This further optimizes interfacial properties between passivation layers, improving long-term reliability. It also helps release thermal stress, preventing interlayer cracking or shedding. It also enhances the stability of the passivation structure in high-temperature and high-humidity environments, extending component life.

[0031] A third aspect of the present invention provides a solar cell cut edge passivation film layer structure or an application of the solar cell cut edge passivation film layer structure prepared by the preparation method in the preparation of solar cells.

[0032] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0033] Example 1 This embodiment provides a solar cell cut edge passivation film structure, the preparation process of which is as follows: Step 1: Prepare a SiO2 layer and a polysilicon layer on the cut edge of the cut cell using the PECVD method; The thickness of the SiO2 tunneling layer is 2 nm, the gas introduced is N2O, the gas flow rate is 8000 sccm, the deposition time is 130 s, and the deposition temperature is 400°C. The thickness of the deposited amorphous silicon layer was 30 nm. PH3, SiH4, and H2 gases were introduced with gas flow rates of PH3: 9000 sccm, SiH4: 3000 sccm, and H2: 2000 sccm, respectively. The deposition time was 500 s and the deposition temperature was 400°C. Step 2: The cell treated in step 1 is annealed at 900°C for 60 minutes to form a 30 nm polysilicon layer. Step 3: After the treatment in step 2, an Al2O3 layer is deposited on the edge of the cell by atomic layer deposition. The thickness of the Al2O3 layer is 20 nm. The gas flow rate is 3:4 with H2O and TMA. The deposition temperature is 250°C. Step 3: The cell processed in step 2 is annealed at a temperature of 300°C for 90 minutes.

[0034] Example 2 This embodiment provides a solar cell cut edge passivation film structure, the preparation process of which is as follows: Step 1: Prepare a SiO2 layer and a polysilicon layer on the cut edge of the cut cell using the PECVD method; The thickness of the SiO2 tunneling layer is 1 nm, the inlet gas is N2O, the gas flow rate is 6000 sccm, the deposition time is 100 s, and the deposition temperature is 350°C. The thickness of the deposited amorphous silicon layer was 10 nm. PH3, SiH4, and H2 gases were introduced at flow rates of 8000 sccm for PH3, 2000 sccm for SiH4, and 2000 sccm for H2, respectively. The deposition time was 300 s and the deposition temperature was 350°C. Step 2: After the treatment in step 1, the cell is annealed at 800°C for 100 minutes to form a 10 nm polysilicon layer. Step 3: After the treatment in step 2, an Al2O3 layer is deposited on the edge of the cell by atomic layer deposition. The thickness of the Al2O3 layer is 30 nm. The gas flow rate of H2O and TMA is 3:4, and the deposition temperature is 200°C. Step 3: The cell treated in step 2 is annealed at a temperature of 200° C. for 150 minutes.

[0035] Example 3 This embodiment provides a solar cell cut edge passivation film structure, the preparation process of which is as follows: Step 1: Prepare a SiO2 layer and a polysilicon layer on the cut edge of the cut cell using the PECVD method; The thickness of the SiO2 tunneling layer was 2.5 nm, the inlet gas was N2O, the gas flow rate was 16000 sccm, the deposition time was 180 s, and the deposition temperature was 500°C. The thickness of the deposited amorphous silicon layer was 50 nm. PH3, SiH4, and H2 gases were introduced with gas flow rates of PH3: 11000 sccm, SiH4: 4000 sccm, and H2: 4000 sccm, respectively. The deposition time was 900 s and the deposition temperature was 500°C. Step 2: After the treatment in step 1, the cell is annealed at a temperature of 1000°C for 20 minutes to form a 50 nm polysilicon layer. Step 3: After the treatment in step 2, an Al2O3 layer is deposited on the edge of the cell by atomic layer deposition. The thickness of the Al2O3 layer is 8 nm. The gas flow rate ratio of H2O and TMA is 3:4, and the deposition temperature is 300°C. Step 3: The cell treated in step 2 is annealed at a temperature of 400°C for 30 minutes.

[0036] Example 4 This embodiment provides a solar cell cut edge passivation film structure, which differs from the first embodiment in that: The thickness of the SiO2 tunneling layer is 0.5 nm, the inlet gas is N2O, the gas flow rate is 5000 sccm, the deposition time is 80 s, and the deposition temperature is 400°C.

[0037] Example 5 This embodiment provides a solar cell cut edge passivation film structure, which differs from the first embodiment in that: The thickness of the SiO2 tunneling layer is 3 nm, the inlet gas is N2O, the gas flow rate is 20000 sccm, the deposition time is 200s, and the deposition temperature is 400℃.

[0038] Example 6 This embodiment provides a solar cell cut edge passivation film structure, which differs from the first embodiment in that: The thickness of the deposited amorphous silicon layer is 5 nm. PH3, SiH4, and H2 gases are introduced with gas flow rates of PH3: 8000 sccm, SiH4: 1000 sccm, and H2: 1000 sccm, respectively; the deposition time is 200 s, and the deposition temperature is 350°C; after annealing, a 5 nm polycrystalline silicon layer is obtained.

[0039] Example 7 This embodiment provides a solar cell cut edge passivation film structure, which differs from the first embodiment in that: The thickness of the deposited amorphous silicon layer is 55 nm. PH3, SiH4, and H2 gases are introduced with gas flow rates of PH3: 12000 sccm, SiH4: 5000 sccm, and H2: 5000 sccm, respectively; the deposition time is 1000 s, and the deposition temperature is 350°C; after annealing, a 55 nm polycrystalline silicon layer is obtained.

[0040] Comparative Example 1 This comparative example provides a solar cell cut edge passivation film structure, which differs from Example 1 in that no tunneling layer is prepared.

[0041] Comparative Example 2 This comparative example provides a solar cell cut edge passivation film structure, which differs from Example 1 in that no polysilicon layer is prepared.

[0042] Comparative Example 3 This comparative example provides a solar cell cut edge passivation film structure, which differs from Example 1 in that no tunneling layer and polysilicon layer are prepared.

[0043] Test Case Test samples: The passivated cells prepared in Examples 1-7 and Comparative Examples 1-3 were used as samples for testing.

[0044] Test method: Use HALM test machine to test battery electrical performance data.

[0045] The test results are shown in Table 1.

[0046] Table 1

[0047] As can be seen from the data in Table 1, through Examples 1-3 and 4-7, it can be seen that the use of a tunneling layer, a polysilicon layer, and an aluminum oxide film layer of a specific thickness, the synergistic effect of the three layers is most conducive to the passivation effect, improving battery efficiency and yield. The thickness of the SiO2 tunneling layer has a significant effect on the passivation effect. Too thin or too thick will affect the interface passivation effect. The thickness of the polysilicon layer plays a key role in charge transfer and passivation synergistic effect. Too thin or too thick may affect carrier transport and interface stability. It can be seen from Example 1 and Comparative Examples 1-3 that a single-structure passivation structure will lead to a decrease in battery efficiency and yield.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solar cell cut edge passivation film structure, characterized in that: include: A tunneling layer, a polysilicon layer and an aluminum oxide film layer are sequentially stacked on the cut edge of the cut solar cell.

2. The solar cell cut edge passivation film structure according to claim 1, wherein: The thickness of the tunneling layer is 1-2.5 nm; Preferably, the material of the tunneling layer is silicon dioxide.

3. The solar cell cut edge passivation film structure according to claim 1, wherein: The thickness of the polysilicon layer is 10-50 nm; Preferably, the polysilicon layer includes a phosphorus-doped polysilicon layer or a boron-doped polysilicon layer.

4. The solar cell cut edge passivation film structure according to claim 1, characterized in that: The thickness of the aluminum oxide film is 8-30 nm.

5. The method for preparing a passivation film structure for cutting edges of a solar cell according to any one of claims 1 to 4, characterized in that: include: The tunneling layer, polysilicon layer and aluminum oxide film layer are stacked in sequence on the cut edge of the cut solar cell.

6. The preparation method according to claim 5, characterized in that The tunneling layer is prepared by a PECVD process; Preferably, the gas used to prepare the tunneling layer includes N2O; the gas flow rate of N2O is 5000-20000 sccm; and the deposition time is 80-200 s; The deposition temperature is 350-500°C.

7. The preparation method according to claim 5, characterized in that The preparation process of the polysilicon layer includes: preparing an amorphous silicon layer by a PECVD process, and then performing an annealing to obtain the polysilicon layer; Preferably, the gases used to prepare the amorphous silicon layer include PH3, SiH4 and H2; the gas flow rate of PH3 is 8000-12000 sccm; the gas flow rate of SiH4 is 1000-5000 sccm; the gas flow rate of H2 is 1000-5000 sccm; the deposition time is 200-1000 s; and the deposition temperature is 350-500° C. Preferably, the temperature of the primary annealing is 800-1000° C.; and the time of the primary annealing is 20-100 min.

8. The preparation method according to claim 5, characterized in that The aluminum oxide film layer is prepared by an atomic layer deposition process; Preferably, the gases used to prepare the aluminum oxide film layer include H2O and TMA; the gas flow ratio of H2O to TMA is 1-5:3-7; and the deposition temperature is 200-300°C.

9. The preparation method according to claim 5, characterized in that Performing secondary annealing after forming the tunneling layer, the polysilicon layer and the aluminum oxide film layer; Preferably, the temperature of the secondary annealing is 200-400°C; Preferably, the secondary annealing time is 30-150 min.

10. Use of the solar cell cut edge passivation film structure according to any one of claims 1 to 4 or the solar cell cut edge passivation film structure prepared by the preparation method according to any one of claims 5 to 9 in preparing solar cells.

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