阅读说明：本技术 太阳能电池的制备方法与太阳能电池 (Preparation method of solar cell and solar cell ) 是由 王俊 吴坚 于 2020-04-23 设计创作，主要内容包括：本申请提供了一种太阳能电池的制备方法与太阳能电池,所述制备方法包括在硅基底的表面制备保护膜,所述硅基底具有相互间隔的至少两个第一区域、位于相邻所述第一区域之间的第二区域；再去除所述第一区域表面的保护膜,并保留所述第二区域表面的保护膜,然后制结使得各所述第一区域形成相互独立的PN结,且所述第二区域在所述保护膜遮蔽下未形成PN结。本申请通过在所述硅基底的第二区域设置保护膜,以在相互间隔的第一区域制得独立的PN结,所述太阳能电池在沿第二区域进行后续分割时,降低相应的子电池片边缘复合,提高填充因子及转换效率。(The preparation method comprises the steps of preparing a protective film on the surface of a silicon substrate, wherein the silicon substrate is provided with at least two first regions which are mutually spaced and a second region which is positioned between the adjacent first regions; and removing the protective film on the surface of the first area, reserving the protective film on the surface of the second area, and then forming junctions so that the first areas form mutually independent PN junctions, and the second area does not form PN junctions under the shielding of the protective film. This application is through the second region of silicon substrate sets up the protection film to make independent PN junction in the first region of mutual interval, solar cell reduces corresponding sub-battery piece edge recombination when following segmentation along the second region, improves fill factor and conversion efficiency.)

1. A method for manufacturing a solar cell, comprising:

preparing a protective film on the surface of a silicon substrate, wherein the silicon substrate is provided with at least two first areas which are mutually spaced and a second area which is positioned between the adjacent first areas;

removing the protective film on the surface of the first area, and reserving the protective film on the surface of the second area;

and preparing junctions, namely preparing PN junctions which are mutually independent in each first region.

2. The method of claim 1, wherein: the protective film is a silicon oxide film layer, and the thickness of the silicon oxide film layer is set to be 20-40 nm.

3. The method of claim 2, wherein: the preparation process of the silicon oxide film layer comprises the steps of putting a silicon substrate into a reaction chamber, wherein the temperature of the reaction chamber is set to be 800-860 ℃;

introducing O into the reaction chamber₂With POCl₃The gas flow ratio of the two is set to be 30: 1-100: 1, and the reaction time is set to be 60-120 min.

4. The method of claim 1, wherein: the protective film is a silicon nitride film layer, and the thickness of the silicon nitride film layer is set to be 80-120 nm.

5. The method of claim 4, wherein: the preparation process of the silicon nitride film layer comprises the steps of putting a silicon substrate into a reaction chamber, wherein the temperature of the reaction chamber is set to be 460-520 ℃;

introducing SiH into the reaction chamber₄And NH₃The gas flow ratio of the two is set to be 1: 10-3: 10, and the reaction time is set to be 35-60 min.

6. The production method according to claim 2 or 4, characterized in that: and after the junction is manufactured, cleaning by adopting HF (hydrogen fluoride) to remove the protective film on the surface of the second area.

7. The method of claim 1, wherein: the "removing the protective film on the surface of the first region" includes removing the protective film on the surface of the first region using a laser so that the surface of the first region is exposed to the outside.

8. The method of claim 1, wherein: the step of removing the protective film on the surface of the first area and reserving the protective film on the surface of the second area comprises the step of removing the protective film on the surface of the first area by etching with corrosive slurry.

9. The method of claim 1, wherein: the preparation method also comprises the step of texturing the silicon substrate before the preparation of the protective film; and the number of the first and second electrodes,

and after the junction is finished, metalizing the silicon substrate, wherein the metalizing step comprises the step of manufacturing an electrode main grid at the edge of the first area adjacent to the second area.

10. A solar cell comprises a silicon substrate and a metal electrode arranged on the surface of the silicon substrate, and is characterized in that: the silicon substrate comprises at least two first regions and a second region located between the adjacent first regions, and PN junctions are formed in the first regions; the second area is shielded by a protective film in the junction making process, so that a PN junction is not formed in the second area.

Technical Field

The invention relates to the technical field of photovoltaic production, in particular to a solar cell and a preparation method thereof.

Background

The crystalline silicon solar cell and the photovoltaic module are still products with the most mature technical development and the most extensive application at present. In recent years, in order to reduce the resistance loss of a photovoltaic module and improve the utilization rate of a light receiving area, novel photovoltaic module products such as a half-chip module and a laminated tile module are receiving more and more attention. The half-piece assembly and the laminated tile assembly need to divide the whole piece of battery piece to obtain the corresponding half-piece battery piece or strip-shaped battery piece, and specifically, the battery piece can be sliced by adopting modes such as laser cutting and mechanical cutting, or the half-piece battery piece or strip-shaped battery piece can be obtained by firstly adopting laser cutting and then adopting a splitting mode.

Generally, the whole cut battery piece is basically consistent with the preparation process of the conventional battery piece, and only certain design adjustment is made according to the electrode pattern. When the whole battery piece is divided, the space charge area recombination at the PN junction position leads to obvious loss of the battery efficiency, and the severe recombination of the space charge area also leads to the reduction of the low-light performance of the battery piece. In other words, the PN junction damage caused by cutting the battery piece will limit the efficiency improvement of the half-chip module and the laminated module to some extent.

In view of the above, it is desirable to provide a novel method for manufacturing a solar cell and a solar cell.

Disclosure of Invention

The invention aims to provide a solar cell and a preparation method thereof, which effectively avoid the recombination of space charge regions caused by the division of the solar cell, are suitable for the manufacture of half-chip components and laminated components and can improve the filling factor and the conversion efficiency.

In order to achieve the above object, the present application provides a method for manufacturing a solar cell, which mainly includes:

preparing a protective film on the surface of a silicon substrate, wherein the silicon substrate is provided with at least two first areas which are mutually spaced and a second area which is positioned between the adjacent first areas;

removing the protective film on the surface of the first area, and reserving the protective film on the surface of the second area;

and preparing junctions, namely preparing PN junctions which are mutually independent in each first region.

As a further improvement of this application, the protection film sets up to the silicon oxide rete, the thickness of silicon oxide rete sets up to 20 ~ 40 nm.

As a further improvement of the application, the preparation process of the silicon oxide film layer comprises the steps of putting a silicon substrate into a reaction chamber, wherein the temperature of the reaction chamber is set to be 800-860 ℃;

introducing O into the reaction chamber₂With POCl₃The gas flow ratio of the two is set to be 30: 1-100: 1, and the reaction time is set to be 60-120 min.

As a further improvement of this application, the protection film sets up to the silicon nitride rete, the thickness of silicon nitride rete sets up to 80 ~ 120 nm.

As a further improvement of the method, the preparation process of the silicon nitride film layer comprises the steps of putting a silicon substrate into a reaction chamber, wherein the temperature of the reaction chamber is set to be 460-520 ℃;

introducing SiH into the reaction chamber₄And NH₃The gas flow ratio of the two is set to be 1: 10-3: 10, and the reaction time is set to be 35-60 min.

As a further improvement of the application, the preparation method further comprises the step of removing the protective film on the surface of the second area by using HF cleaning after the junction is formed.

As a further improvement of the present application, the "removing the protective film on the surface of the first region" includes removing the protective film on the surface of the first region with a laser, so that the surface of the first region is exposed to the outside.

As a further improvement of the present application, the "removing the protective film on the surface of the first region and retaining the protective film on the surface of the second region" includes etching and removing the protective film on the surface of the first region with an etching slurry.

As a further improvement of the present application, the preparation method further comprises texturing the silicon substrate before the preparation of the protective film; and the number of the first and second electrodes,

and after the junction is finished, metalizing the silicon substrate, wherein the metalizing step comprises the step of manufacturing an electrode main grid at the edge of the first area adjacent to the second area.

The application also provides a solar cell, which comprises a silicon substrate and a metal electrode arranged on the surface of the silicon substrate, wherein the silicon substrate comprises at least two first regions and a second region positioned between the adjacent first regions, and PN junctions are formed in the first regions; the second area is shielded by a protective film in the junction making process, so that a PN junction is not formed in the second area.

The beneficial effect of this application is: by adopting the preparation method and the solar cell, the second region is shielded by the protective film in the junction preparation process, and the silicon substrate forms mutually independent PN junctions only in each first region; when the solar cell is divided from the second region, the composition of the space charge region can not be generated, the filling factor and the conversion efficiency of the corresponding sub-cell can be effectively improved, and the solar cell is suitable for the production and the manufacture of half-chip assemblies and laminated assemblies.

Drawings

FIG. 1 is a schematic main flow chart of a method for manufacturing a solar cell according to the present application;

FIG. 2 is a schematic cross-sectional view of a preferred embodiment of the solar cell of the present application;

FIG. 3 is a schematic plan view of the solar cell of FIG. 2;

FIG. 4 is a schematic structural diagram of a process of preparing a protective film on the surface of a silicon substrate;

FIG. 5 is a schematic view showing the case where the protective film on the surface of the first region of the silicon substrate in FIG. 4 is removed;

fig. 6 is a schematic cross-sectional view of another preferred embodiment of the solar cell of the present application.

Detailed Description

The present invention will be described in detail below with reference to embodiments shown in the drawings. The present invention is not limited to the embodiment, and structural, methodological, or functional changes made by one of ordinary skill in the art according to the embodiment are included in the scope of the present invention.

Referring to fig. 1 to 5, the present application provides a method for manufacturing a solar cell and a solar cell 100 manufactured by the method.

The preparation method mainly comprises the following steps:

texturing a silicon substrate 1, wherein the silicon substrate 1 is a monocrystalline or polycrystalline silicon wafer with a given specification, and the silicon substrate 1 is provided with at least two first areas 11 which are mutually spaced and a second area 12 which is positioned between the adjacent first areas 11;

preparing a protective film 5 on the surface of the silicon substrate 1;

removing the protective film 5 on the surface of the first area 11 and reserving the protective film 5 on the surface of the second area 12;

preparing junctions, namely preparing PN junctions which are mutually independent in each first region 11;

etching the edge, and removing the PN junction at the edge of the silicon substrate 1;

coating;

and (4) metalizing, and preparing a metal electrode on the surface of the silicon substrate 1.

The first region 11 of the silicon substrate 1 corresponds to a sub-cell region obtained by subsequently dividing the solar cell 100, and the second region 12 corresponds to a dividing region adjacent to the first region 11. The protective film 5 can prevent doping elements such as phosphorus and boron from entering the second region 12 and prevent the second region 12 from forming a PN junction in the process of carrying out integral diffusion and junction making on the silicon substrate 1, so that the solar cell 100 does not generate the composition of a space charge region after being divided, and the filling factor and the conversion efficiency of the corresponding sub-cell are effectively improved.

In the embodiment, taking a P-type silicon wafer as an example, after the silicon substrate 1 is subjected to texturing by an acid solution or an alkali solution, a silicon oxide film layer is prepared on the surface of the silicon substrate and serves as a protective film 5, and the thickness of the silicon oxide film layer is set to be 20-40 nm.

The preparation process of the silicon oxide film layer comprises the steps of putting the silicon substrate 1 into a reaction chamber, wherein the temperature of the reaction chamber is set to be 800-860 ℃;

introducing O into the reaction chamber₂With POCl₃The gas flow ratio of the two is set to be 30: 1-100: 1, and the reaction time is set to be 60-120 min.

Specifically, the reaction chamber can adopt a tubular diffusion furnace, namely, the existing tubular diffusion furnace is used for carrying out thermal oxidation on the surface of a silicon wafer to generate a corresponding silicon oxide film layer, and a small amount of POCl is introduced into the reaction chamber₃And is beneficial to generating a silicon oxide film with stable performance and improving the reaction speed. Particularly, if the silicon substrate 1 is an N-type silicon wafer, oxygen may be directly introduced after the reaction chamber is evacuated, and a corresponding silicon oxide film layer is prepared by thermal oxidation, and the thickness of the silicon oxide film layer may be appropriately increased due to the relatively high temperature of the subsequent boron diffusion of the N-type silicon wafer.

In other embodiments of the present invention, the protective film 5 may also be a silicon nitride film layer, and the thickness of the silicon nitride film layer is set to be 80 to 120 nm.

The preparation process of the silicon nitride film layer comprises the steps of putting a silicon substrate 1 into a reaction chamber, wherein the temperature of the reaction chamber is set to be 460-520 ℃, and the reaction chamber can be a deposition chamber of PECVD equipment;

introducing SiH into the reaction chamber₄And NH₃The gas flow ratio of the two is set to be 1: 10-3: 10, and the reaction time is set to be 35-60 min.

The "removing the protective film 5 on the surface of the first region 11" may be performed by removing the protective film 5 on the surface of the first region 11 with laser, so that the surface of the first region 11 is exposed outwards, or removing the protective film 5 on the surface of the first region 11 by etching with etching slurry, where the etching slurry may be accurately printed on the surface of the first region 11 by using a screen printing method, and then cleaning is performed after the etching is completed, so that the surface of the first region 11 is exposed outwards. Specifically, deionized water and an ultrasonic device can be adopted to effectively clean the silicon substrate 1, so that surface residues can be removed.

Here, the step of forming a junction is specifically carried out using POCl₃Performing whole-surface diffusion on the front surface of the silicon substrate 1 as a phosphorus source, wherein the first region 11 forms a corresponding PN junction (shown by a dotted line in FIG. 2); and the second region 12 is shielded by the protective film 5, and a PN junction is not formed.

After the junction is formed, the edge PN junction formed in the silicon substrate 1 during the junction forming process is removed by etching through the edge etching step, and after the edge etching is completed, the surface of the silicon substrate 1 is cleaned by using HF to remove residual phosphosilicate glass (PSG), and generally, the two steps are integrated into the same device to process the silicon substrate 1. Here, in order to remove the protective film 5 on the surface of the second region 12, the HF cleaning process may be adjusted accordingly, and the concentration of the HF solution and the surface cleaning time may be increased appropriately, so that the protective film 5 on the surface of the second region 12 may be effectively removed. By way of illustration, we can increase the concentration of the HF solution from 4% to 8% while extending the cleaning time from 10s to 60 s. The surface of the silicon substrate 1 treated by the cleaning step has no residual protective film 5, so that the surface color of the silicon substrate 1 after subsequent film coating is more uniform, and the product attractiveness is improved.

The coating step comprises the steps of preparing an antireflection film 2 on the front surface of the silicon substrate 1 in a deposition mode, and preparing a back passivation film 3 on the back surface of the silicon substrate 1 in a deposition mode. For a P-type silicon wafer, the anti-reflection film 2 can be a silicon nitride film or a silicon oxide film or a composite film layer composed of a silicon nitride film and a silicon oxide film, and is generally deposited by using a PECVD method; the back passivation film 3 may be set to Al₂O₃Film layer of Al₂O₃The film layer is suitable for passivation of the back surface of the P-type silicon substrate 1 and can be deposited by using an ALD process. The thicknesses and specific film layer structures of the antireflection film 2 and the back passivation film 3 can be adjusted through gas flow, reaction time, temperature and the like. Of course, in other embodiments of the present invention, only the first embodiment may be usedAnd arranging an antireflection film 2 on the front surface of the silicon substrate 1.

The metallization step is mainly to prepare metal electrodes on the surface of the coated silicon substrate 1, wherein the metal electrodes include a front electrode and a back electrode (not shown) obtained by screen printing and sintering. Specifically, the front electrode includes an electrode main grid 4 disposed at the edge of the first region 11 adjacent to the second region 12, and the cell main grid 4 of the first region 11 may also be disposed along the edge of the solar cell 100. For the back electrode, a groove penetrating through the back passivation film 3 may be formed on the back surface of the silicon substrate 1 by laser, so that the corresponding paste may form a good ohmic contact with the silicon substrate 1 after sintering. The metal electrodes of each first region 11 can be communicated with each other to facilitate the cell test; the metal electrodes corresponding to the first regions 11 may be provided independently of each other.

Referring to fig. 6, another embodiment of the solar cell 100 of the present invention is shown, which is different from the previous embodiment in that: after the junction is formed, the protective film 5 on the surface of the second region 12 is not completely cleaned and removed, which does not substantially affect the performance of the solar cell 100, but after the antireflective film 2 is deposited on the silicon substrate 1, a certain color difference exists between the first region 11 and the second region 12, which affects the appearance of the solar cell 100 and the sub-cell slices obtained by dividing the solar cell 100 to a certain extent.

It should be noted that, in the above embodiment, the solar cell 100 includes two first regions 11 and a second region disposed between the two first regions 11, in other words, the solar cell 100 can be divided into corresponding half-chip cells. Obviously, the solar cell 100 may include a plurality of strip-shaped first regions 11 arranged in sequence to obtain corresponding strip-shaped cells through division, which is not described in detail herein.

In summary, in the preparation method of the present application, the second region 12 is shielded by the protective film 5 during the junction preparation process, the silicon substrate 1 forms the PN junction independent of each other only in each first region 11, and the PN junction is not formed in the second region 12. When the solar cell 100 is divided by the second region 12, the recombination of space charge regions is not generated, the filling factor and the conversion efficiency of the corresponding sub-cell sheet are effectively improved, and the solar cell is suitable for the production and the manufacture of half-sheet assemblies and laminated assemblies.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.