WO2020211207A1 - Bifacial solar cell and preparation method therefor - Google Patents

Abstract

A bifacial solar cell and a preparation method therefor. The bifacial solar cell comprises a P-type substrate layer; a first doping layer located on a first surface of the P-type substrate layer, with the first doping layer comprising a first heavily-doped region and a first lightly-doped region surrounding an outer edge of the first heavily-doped region; a first passivation layer located on an upper surface of the first doping layer; a first electrode located on an upper surface of the first passivation layer, with the first electrode being in contact with the first heavily-doped region; a second doping layer located on a second surface of the P-type substrate layer, with the second doping layer comprising a second heavily-doped region and a second lightly-doped region; a second passivation layer located on a lower surface of the second doping layer; and a second electrode located on a lower surface of the second passivation layer, wherein the first surface is opposite the second surface. According to the bifacial solar cell in the present application, selective emitter technology is used on both a first surface and a second surface of the cell, such that the photoelectric conversion efficiency is further improved.

Description

Double-sided solar cell and preparation method thereof

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on April 18, 2019, the application number is 201910313303.1, and the invention title is "a double-sided solar cell and its preparation method", the entire content of which is incorporated by reference In this application.

Technical field

This application relates to the technical field of solar cells, in particular to a double-sided solar cell and a preparation method thereof.

Background technique

With the development of society, energy consumption has increased sharply, and the energy crisis is the focus of attention of all countries in the world. In order to alleviate the energy crisis, making full use of renewable energy is an effective measure. Solar energy is a kind of green and environmentally friendly renewable energy with unlimited reserves and will not produce any pollutants such as waste water and waste residue. Therefore, the photovoltaic industry has developed rapidly in recent years.

Improving the photoelectric conversion efficiency of solar cells has always been the goal pursued by the photovoltaic industry. In recent years, by improving the quality of silicon wafers and the performance of the slurry, the photoelectric conversion efficiency of solar cells has been improved. However, the efficiency improvement of single-sided solar cells has reached a bottleneck period. The appearance of double-sided solar cells has further improved the photoelectric conversion efficiency of solar cells.

PERT battery (Passivated Emitter and Rear Totally-diffused cell, a fully diffused cell on the back surface of the passivated emitter), is a typical double-sided solar cell. By using selective emitter technology on the back of the battery, the photoelectric conversion of the battery is achieved. The efficiency is improved, but the degree of improvement in photoelectric conversion efficiency is limited.

Summary of the invention

The purpose of this application is to provide a double-sided solar cell and a preparation method thereof to improve the photoelectric conversion efficiency of the double-sided solar cell.

To solve the above technical problems, this application provides a double-sided solar cell, including:

P-type substrate layer;

A first doped layer located on the first surface of the P-type substrate layer, the first doped layer including a first heavily doped region and a first lightly doped layer surrounding the outer edge of the first heavily doped region Area;

A first passivation layer located on the upper surface of the first doped layer;

A first electrode located on the upper surface of the first passivation layer, and the first electrode is in contact with the first heavily doped region;

A second doped layer located on the second surface of the P-type substrate layer, the second doped layer including a second heavily doped region and a second lightly doped region;

A second passivation layer located on the lower surface of the second doped layer;

A second electrode located on the lower surface of the second passivation layer;

Wherein, the first surface is opposite to the second surface.

Optionally, the second electrode is an electrode formed of silver aluminum paste.

Optionally, the first passivation layer includes:

A first silicon oxide layer located on the upper surface of the first doped layer;

A first silicon nitride layer located on the upper surface of the first silicon oxide layer.

Optionally, the second passivation layer includes:

A second silicon dioxide layer located on the lower surface of the second doped layer;

An aluminum oxide layer located on the lower surface of the second silicon dioxide layer;

A second silicon nitride layer located on the lower surface of the aluminum oxide layer.

Optionally, the thickness of the first silicon nitride layer ranges from 65 nm to 90 nm, inclusive.

Optionally, the thickness of the aluminum oxide layer ranges from 4 nm to 20 nm, inclusive.

Optionally, the thickness of the second silicon nitride layer ranges from 65 nm to 140 nm, inclusive.

Optionally, the length of the second heavily doped region in a direction parallel to the second surface of the P-type substrate layer ranges from 100 μm to 160 μm, inclusive.

This application also provides a method for preparing a double-sided solar cell, including:

Forming a first doped layer on the first surface of the P-type substrate layer, the first doped layer including a first heavily doped region and a first lightly doped region surrounding an outer edge of the first heavily doped region;

Forming a first passivation layer on the upper surface of the first doped layer;

Forming a first electrode on the upper surface of the first passivation layer, and the first electrode is in contact with the first heavily doped region;

Forming a second doped layer on the second surface of the P-type substrate layer, the second doped layer including a second heavily doped region and a second lightly doped region;

Forming a second passivation layer on the lower surface of the second doped layer;

Forming a second electrode on the lower surface of the second passivation layer;

Wherein, the first surface is opposite to the second surface.

Optionally, after the second electrode is formed on the lower surface of the second passivation layer, the method further includes:

Carry out anti-light decay treatment.

The double-sided solar cell and the preparation method thereof provided in the present application include a P-type substrate layer; a first doped layer on the first surface of the P-type substrate layer, and the first doped layer includes a first heavily doped layer Area and a first lightly doped area surrounding the outer edge of the first heavily doped area; a first passivation layer located on the upper surface of the first doped layer; a first passivation layer located on the upper surface of the first passivation layer A first electrode, and the first electrode is in contact with the first heavily doped region; a second doped layer on the second surface of the P-type substrate layer, the second doped layer includes a second heavily doped A miscellaneous region and a second lightly doped region; a second passivation layer located on the lower surface of the second doped layer; a second electrode located on the lower surface of the second passivation layer; wherein, the first surface and The second surface is opposite. It can be seen that the bifacial solar cell in the present application has a first doped layer and a second doped layer on the first surface and the second surface of the battery, and the first doped layer includes a first heavily doped region and a surrounding area. In the first lightly doped region at the outer edge of the first heavily doped region, the second doped layer includes a second heavily doped region and a second lightly doped region, that is, on the first surface and the second surface of the battery All adopt selective emitter technology to reduce the surface recombination of carriers, improve the passivation effect, and reduce the ohmic contact resistance of the metal electrode. Compared with the double-sided solar cell in the prior art, the photoelectric conversion efficiency is further improved.

Description of the drawings

In order to more clearly describe the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely For some of the embodiments of the application, for those of ordinary skill in the art, other drawings may be obtained based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a double-sided solar cell provided by an embodiment of the application;

FIG. 2 is a flowchart of a method for manufacturing a double-sided solar cell provided by an embodiment of the application.

detailed description

In order to enable those skilled in the art to better understand the solution of the application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

In the following description, many specific details are explained in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do so without departing from the connotation of the present invention. Similar promotion, therefore, the present invention is not limited by the specific embodiments disclosed below.

As mentioned in the background art section, the existing double-sided solar cell uses selective emitter technology on the back of the cell to improve the photoelectric conversion efficiency of the cell, but the improvement of the photoelectric conversion efficiency is limited.

In view of this, this application provides a double-sided solar cell. Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a double-sided solar cell provided by an embodiment of the application, including:

P-type substrate layer 1;

Specifically, the P-type substrate layer 1 is P-type crystalline silicon.

The first doped layer 2 is located on the first surface of the P-type substrate layer 1. The first doped layer 2 includes a first heavily doped region 21 and an outer edge of the first heavily doped region 21 The first lightly doped region 22;

It should be pointed out that the first surface is the front side of the double-sided solar cell, that is, the surface facing the sun.

It should also be pointed out that the doping concentration of the first heavily doped region 21 is higher than that of the first lightly doped region 22, and the first heavily doped region 21 is surrounded by the first lightly doped region 22; the first doped layer 2 The surface away from the P-type substrate layer 1 is a flat surface. In the direction from the first doped layer 2 to the P-type substrate layer 1, the height of the first heavily doped region 21 is higher than that of the first lightly doped region 22 .

Specifically, the first doped layer 2 is a doped layer formed by doping with a group 5A element (such as phosphorus), wherein the square resistance of the first heavily doped region 21 ranges from 60 ohm/□ to 90 ohm/□, including The endpoint value, the square resistance of the first lightly doped region 22 ranges from 100 ohm/□ to 130 ohm/□, including the endpoint value.

A first passivation layer 3 located on the upper surface of the first doped layer 2;

In one embodiment of the present application, the first passivation layer 3 is a first silicon nitride layer, but this embodiment does not limit this. In another embodiment of the present application, the first passivation layer 3 includes The first silicon oxide layer located on the upper surface of the first doped layer 2 and the first silicon nitride layer located on the upper surface of the first silicon oxide layer to enhance the passivation effect of the double-sided solar cell and block current carrying The recombination of particles on the surface of the double-sided solar cell improves the photoelectric conversion efficiency of the double-sided solar cell.

A first electrode 4 located on the upper surface of the first passivation layer 3, and the first electrode 4 is in contact with the first heavily doped region 21;

Specifically, the first electrode 4 needs to be completely in contact with the first heavily doped region 21, and the first electrode 4 is a silver electrode. The first heavily doped region 21 has a high doping concentration, and the resistance of the contact area between the first electrode 4 and the first heavily doped region 21 is small, which is beneficial to improve the photoelectric conversion efficiency of the bifacial solar cell; the first lightly doped region 22 is doped The low impurity concentration can reduce the surface recombination rate of carriers, which is beneficial to the improvement of the photoelectric conversion efficiency of the double-sided solar cell.

The second doped layer 5 located on the second surface of the P-type substrate layer 1, the second doped layer 5 includes a second heavily doped region 51 and a second lightly doped region 52;

Specifically, the second doped layer 5 is a doped layer formed by doping with a group 3A element (such as boron), wherein the square resistance of the second heavily doped region 51 ranges from 60 ohm/□ to 90 ohm/□, including The endpoint value, the square resistance of the second lightly doped region 52 ranges from 100 ohm/□ to 130 ohm/□, including the endpoint value.

It should be noted that the doping concentration of the second heavily doped region 51 is higher than that of the second lightly doped region 52, and the second heavily doped region 51 is surrounded by the second lightly doped region 52; The surface away from the P-type substrate layer 1 is a flat surface. In the direction from the second doped layer 5 to the P-type substrate layer 1, the height of the second heavily doped region 51 is higher than the second lightly doped region 52.

A second passivation layer 6 located on the lower surface of the second doped layer 5;

In an embodiment of the present application, the second passivation layer 6 includes an aluminum oxide layer located on the lower surface of the second doped layer 5 and a second silicon nitride layer located on the lower surface of the aluminum oxide layer. Without limitation, in another embodiment of the present application, the second passivation layer 6 includes a second silicon dioxide layer located on the lower surface of the second doped layer 5, and a second silicon dioxide layer located on the lower surface of the second silicon dioxide layer. The aluminum oxide layer and the second silicon nitride layer located on the lower surface of the aluminum oxide layer enhance the passivation effect of the double-sided solar cell, block the recombination of carriers on the surface of the double-sided solar cell, and improve the performance of the double-sided solar cell. Photoelectric conversion efficiency.

A second electrode 7 located on the lower surface of the second passivation layer 6;

It should be noted that the second electrode 7 needs to be in full contact with the second heavily doped region 51.

Wherein, the first surface is opposite to the second surface.

Preferably, in an embodiment of the present application, the second electrode 7 is an electrode formed of silver-aluminum paste. Because the plasticity of the silver-aluminum paste is better, it can penetrate the silicon nitride layer and does not need to be on both sides. The laser opening on the back of the solar cell has a simpler process, and the contact resistance between the second electrode 7 and the second heavily doped region 51 is lower, which is beneficial to improve the photoelectric conversion efficiency.

The double-sided solar cell provided by this embodiment includes a P-type substrate layer 1; a first doped layer 2 on the first surface of the P-type substrate layer 1, and the first doped layer 2 includes a first heavily doped layer The impurity region 21 and the first lightly doped region 22 surrounding the outer edge of the first heavily doped region 21; the first passivation layer 3 located on the upper surface of the first doped layer 2; The first electrode 4 on the upper surface of the passivation layer 3, and the first electrode 4 is in contact with the first heavily doped region 21; the second doped layer 5 on the second surface of the P-type substrate layer 1, The second doped layer 5 includes a second heavily doped region 51 and a second lightly doped region 52; a second passivation layer 6 located on the lower surface of the second doped layer 5; The second electrode 7 on the lower surface of the chemical layer 6; wherein, the first surface is opposite to the second surface. It can be seen that the double-sided solar cell in this embodiment has a first doped layer 2 and a second doped layer 5 on the first surface and the second surface of the battery, and the first doped layer 2 includes the first heavily doped The impurity region 21 and the first lightly doped region 22 surrounding the outer edge of the first heavily doped region 21, the second doped layer 5 includes a second heavily doped region 51 and a second lightly doped region 52, namely The selective emitter technology is adopted on both the first surface and the second surface of the battery. Compared with the double-sided solar cell in the prior art, the photoelectric conversion efficiency is further improved.

The P-type substrate layer 1 is P-type crystalline silicon, that is, the bifacial solar cell is a P-type PERT cell, which improves the photoelectric conversion efficiency of the P-type PERT cell, and at the same time broadens the research of the P-type PERT cell, making the application range of the P-type PERT cell More extensive.

Preferably, in an embodiment of the present application, the thickness of the first silicon nitride layer ranges from 65 nm to 90 nm, inclusive. Avoid that the thickness of the first silicon nitride layer is too small to prevent the recombination of carriers on the front side of the double-sided solar cell, so that the photoelectric conversion efficiency of the double-sided solar cell is low, and the first silicon nitride layer is avoided at the same time. If the thickness is too large, the manufacturing cost will increase, the process time will be prolonged, and the manufacturing efficiency of the double-sided solar cell will be reduced.

Preferably, in an embodiment of the present application, the thickness of the aluminum oxide layer ranges from 4 nm to 20 nm, inclusive. Avoid the thickness of the aluminum oxide layer is too small, the passivation effect is poor, resulting in low photoelectric conversion efficiency of the double-sided solar cell, while avoiding the thickness of the aluminum oxide layer is too large, on the one hand, increase the cost of the double-sided solar cell, on the other hand, The production time of double-sided solar cells is prolonged and the production efficiency is reduced.

Preferably, the thickness of the first silicon oxide layer ranges from 1 nm to 3 nm, inclusive. Further, the thickness of the second silicon dioxide layer ranges from 1 nm to 3 nm, inclusive.

Preferably, in an embodiment of the present application, the thickness of the second silicon nitride layer ranges from 65 nm to 140 nm, inclusive. Avoid excessively small thickness of the second silicon nitride layer, resulting in poor passivation on the back of the double-sided solar cell, resulting in low photoelectric conversion efficiency of the double-sided solar cell, and avoiding the thickness of the second silicon nitride layer from being too large, resulting in manufacturing costs Increase and extend the process time at the same time, reduce the production efficiency of double-sided solar cells.

Preferably, in an embodiment of the present application, the length of the second heavily doped region 51 in a direction parallel to the second surface of the P-type substrate layer 1 ranges from 100 μm to 160 μm, including endpoints . Avoid that the length of the second heavily doped region 51 in the direction parallel to the second surface of the P-type substrate layer 1 is too small. Since the second electrode 7 needs to be in contact with the second heavily doped region 51, if the length is too small, It is not conducive to the complete contact of the second electrode 7 with the second heavily doped region 51, which increases the difficulty of aligning the second electrode 7 with the second heavily doped region 51; at the same time, avoid excessive length, that is, avoid the second heavily doped region The area of 51 is too large, so that the carrier surface recombination rate increases, thereby reducing the photoelectric conversion efficiency.

This application also provides a method for preparing a double-sided solar cell. Please refer to FIG. 2. FIG. 2 is a flowchart of a method for preparing a double-sided solar cell provided by an embodiment of the application, including:

Step S101: A first doped layer is formed on the first surface of the P-type substrate layer. The first doped layer includes a first heavily doped region and a first lightly doped layer surrounding the outer edge of the first heavily doped region. Miscellaneous area

Specifically, P-type crystalline silicon can be selected for the P-type substrate layer.

Preferably, before the first doped layer is formed on the first surface of the P-type substrate layer, the P-type substrate layer is placed in an alkaline solution for texturing, so that the thickness of the P-type substrate layer is between 0.3 g and 0.8 g. A pyramid structure is formed on the surface of the P-type substrate layer to increase the light trapping effect of the P-type substrate layer; further, the second surface of the P-type substrate layer is etched and polished to a depth of 3 μm to 8 μm, so that the second surface The reflectivity is above 40%.

Preferably, the first doped layer is formed by an ion implantation method, and the doping concentration of the first heavily doped region is higher than that of the first lightly doped region, which facilitates the control of doping concentration and doping accuracy, and the operation is simple. The formed first doped layer is a doped layer formed by doping with a group 5A element (such as phosphorus), and the square resistance of the first heavily doped region is controlled to range from 60ohm/□ to 90ohm/□, including the endpoint value, control The square resistance of the first lightly doped region ranges from 100 ohm/□ to 130 ohm/□, including the endpoint value.

Step S102: forming a first passivation layer on the upper surface of the first doped layer;

Specifically, a first silicon nitride layer is formed on the upper surface of the first doped layer.

Preferably, before forming the first silicon nitride layer on the upper surface of the first doped layer, the method further comprises: forming a first silicon oxide layer on the upper surface of the first doped layer by annealing and oxidation at 600°C to 800°C, correspondingly Yes, a first silicon nitride layer is formed on the upper surface of the first silicon oxide layer to enhance the passivation effect of the double-sided solar cell, block the recombination of carriers on the surface of the double-sided solar cell, and improve the photoelectric conversion of the double-sided solar cell effectiveness. Further, the thickness of the first silicon oxide layer is controlled to be between 1 nm and 3 nm, including the endpoint value.

It should be pointed out that the method for forming the first passivation layer is not specifically limited in this embodiment, and it depends on the situation. For example, chemical vapor deposition method, sputtering method, etc.

Preferably, the thickness of the first silicon nitride layer is controlled to be between 65 nm and 90 nm, including the endpoint value. Avoid that the thickness of the first silicon nitride layer is too small to prevent the recombination of carriers on the front side of the double-sided solar cell, so that the photoelectric conversion efficiency of the double-sided solar cell is low, and the first silicon nitride layer is avoided at the same time. If the thickness is too large, the manufacturing cost will increase, the process time will be prolonged, and the manufacturing efficiency of the double-sided solar cell will be reduced.

Step S103: forming a first electrode on the upper surface of the first passivation layer, and the first electrode is in contact with the first heavily doped region;

Specifically, a silver electrode is formed on the upper surface of the first passivation layer by using a screen printing technology, and the silver electrode is in complete contact with the first heavily doped region.

Step S104: forming a second doped layer on the second surface of the P-type substrate layer, the second doped layer including a second heavily doped region and a second lightly doped region;

Preferably, an ion implantation method is used to form the second doped layer, and the doping concentration of the second heavily doped region is higher than that of the second lightly doped region, which facilitates the control of doping concentration and doping accuracy, and the operation is simple. The second doped layer is a doped layer formed by doping with a group 3A element (such as boron). The square resistance of the second heavily doped area is controlled to be between 60ohm/□ and 90ohm/□, including the endpoint value, and the first The square resistance of the two lightly doped regions ranges from 100 ohm/□ to 130 ohm/□, including the endpoint value.

It should be pointed out that the doping concentration of the second heavily doped region is higher than that of the second lightly doped region, which is surrounded by the second lightly doped region; the second doped layer is far away from the P-type substrate layer The surface of is a flat surface, and in the direction from the second doped layer to the P-type substrate layer, the height of the second heavily doped region is higher than the second lightly doped region.

Preferably, the length of the second heavily doped region in a direction parallel to the second surface of the P-type substrate layer is controlled to have a value ranging from 100 μm to 160 μm, inclusive. Avoid that the length of the second heavily doped region in the direction parallel to the second surface of the P-type substrate layer is too small. Since the second electrode needs to be in contact with the second heavily doped region, if the length is too small, it is not conducive to the second The electrode is in complete contact with the second heavily doped region, which increases the difficulty of aligning the second electrode with the second heavily doped region; at the same time, avoid excessive length, that is, avoid the area of the second heavily doped region from being too large, causing current carrying The sub-surface recombination rate increases, thereby reducing the photoelectric conversion efficiency.

Step S105: forming a second passivation layer on the lower surface of the second doped layer;

Specifically, an aluminum oxide layer is formed on the lower surface of the second doped layer; a second silicon nitride layer is formed on the lower surface of the aluminum oxide layer.

Preferably, before forming the aluminum oxide layer on the lower surface of the second doped layer, the method further includes: forming a second silicon dioxide layer on the lower surface of the second doped layer by annealing and oxidation at 600°C to 800°C. In order to enhance the passivation effect of the double-sided solar cell, block the recombination of carriers on the surface of the double-sided solar cell, and improve the photoelectric conversion efficiency of the double-sided solar cell. Further, the thickness of the second silicon dioxide layer is controlled to be between 1 nm and 3 nm, including the endpoint value.

It should be pointed out that the method for forming the second passivation layer is not limited in this embodiment, and it depends on the situation, for example, chemical vapor deposition method, magnetron sputtering method, etc.

Preferably, the thickness of the controlled aluminum oxide layer is between 4 nm and 20 nm, including the endpoint value. Avoid the thickness of the aluminum oxide layer is too small, the passivation effect is poor, resulting in low photoelectric conversion efficiency of the double-sided solar cell, while avoiding the thickness of the aluminum oxide layer is too large, on the one hand, increase the cost of the double-sided solar cell, on the other hand, The production time of double-sided solar cells is prolonged and the production efficiency is reduced.

Preferably, the thickness of the second silicon nitride layer is controlled to be between 65 nm and 140 nm, including the endpoint value. Avoid excessively small thickness of the second silicon nitride layer, resulting in poor passivation on the back of the double-sided solar cell, resulting in low photoelectric conversion efficiency of the double-sided solar cell, and avoiding the thickness of the second silicon nitride layer from being too large, resulting in manufacturing costs Increase and extend the process time at the same time, reduce the production efficiency of double-sided solar cells.

Step S106: forming a second electrode on the lower surface of the second passivation layer;

Preferably, a silver-aluminum electrode is formed on the lower surface of the second passivation layer by using a screen printing method. Since the plasticity of the silver-aluminum paste is better, it can penetrate the silicon nitride layer and does not require laser opening on the back of the double-sided solar cell. Hole, the process is simpler, and the contact resistance between the second electrode and the second heavily doped region is lower, which is beneficial to improve the photoelectric conversion efficiency.

Wherein, the first surface is opposite to the second surface.

On the basis of the foregoing embodiment, in an embodiment of the present application, after the second electrode is formed on the lower surface of the second passivation layer, the method further includes:

Anti-light decay treatment to improve the stability of the output power of the double-sided solar cell.

The method of anti-light decay treatment in this embodiment is not limited. Electric injection can be used for anti-light decay treatment, and light injection can also be used for anti-light decay treatment.

The double-sided solar cell produced by the double-sided solar cell manufacturing method provided in this embodiment includes a P-type substrate layer; a first doped layer on the first surface of the P-type substrate layer, and the first doped layer includes A first heavily doped region and a first lightly doped region surrounding the outer edge of the first heavily doped region; a first passivation layer located on the upper surface of the first doped layer; located on the first passivation layer The first electrode on the upper surface of the chemical layer, and the first electrode is in contact with the first heavily doped region; the second doped layer on the second surface of the P-type substrate layer, the second doped layer It includes a second heavily doped region and a second lightly doped region; a second passivation layer located on the lower surface of the second doped layer; a second electrode located on the lower surface of the second passivation layer; wherein The first surface is opposite to the second surface. It can be seen that the double-sided solar cell manufactured in this embodiment has a first doped layer and a second doped layer on the first surface and the second surface of the battery, and the first doped layer includes a first heavily doped region And the first lightly doped region surrounding the outer edge of the first heavily doped region, the second doped layer includes a second heavily doped region and a second lightly doped region, that is, on the first surface and the first surface of the battery Both surfaces adopt selective emitter technology. Compared with the double-sided solar cell in the prior art, the photoelectric conversion efficiency is further improved.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method part.

The double-sided solar cell provided by the present application and the preparation method thereof are described in detail above. Specific examples are used in this article to describe the principles and implementation of the application. The description of the above examples is only used to help understand the method and core ideas of the application. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims (10)

A double-sided solar cell is characterized in that it comprises: P-type substrate layer; A first doped layer located on the first surface of the P-type substrate layer, the first doped layer including a first heavily doped region and a first lightly doped layer surrounding the outer edge of the first heavily doped region Area; A first passivation layer located on the upper surface of the first doped layer; A first electrode located on the upper surface of the first passivation layer, and the first electrode is in contact with the first heavily doped region; A second doped layer located on the second surface of the P-type substrate layer, the second doped layer including a second heavily doped region and a second lightly doped region; A second passivation layer located on the lower surface of the second doped layer; A second electrode located on the lower surface of the second passivation layer; Wherein, the first surface is opposite to the second surface. The double-sided solar cell of claim 1, wherein the second electrode is an electrode formed of silver aluminum paste. The double-sided solar cell of claim 1, wherein the first passivation layer comprises: A first silicon oxide layer located on the upper surface of the first doped layer; A first silicon nitride layer located on the upper surface of the first silicon oxide layer. The double-sided solar cell of claim 1, wherein the second passivation layer comprises: A second silicon dioxide layer located on the lower surface of the second doped layer; An aluminum oxide layer located on the lower surface of the second silicon dioxide layer; A second silicon nitride layer located on the lower surface of the aluminum oxide layer. The double-sided solar cell of claim 3, wherein the thickness of the first silicon nitride layer ranges from 65 nm to 90 nm, inclusive. The double-sided solar cell of claim 4, wherein the thickness of the aluminum oxide layer ranges from 4 nm to 20 nm, inclusive. The double-sided solar cell of claim 4, wherein the thickness of the second silicon nitride layer ranges from 65 nm to 140 nm, inclusive. The double-sided solar cell of claim 1, wherein the length of the second heavily doped region in a direction parallel to the second surface of the P-type substrate layer ranges from 100 μm to 160 μm, including Endpoint value. A method for preparing a double-sided solar cell, characterized in that it comprises: Forming a first doped layer on the first surface of the P-type substrate layer, the first doped layer including a first heavily doped region and a first lightly doped region surrounding an outer edge of the first heavily doped region; Forming a first passivation layer on the upper surface of the first doped layer; Forming a first electrode on the upper surface of the first passivation layer, and the first electrode is in contact with the first heavily doped region; Forming a second doped layer on the second surface of the P-type substrate layer, the second doped layer including a second heavily doped region and a second lightly doped region; Forming a second passivation layer on the lower surface of the second doped layer; Forming a second electrode on the lower surface of the second passivation layer; Wherein, the first surface is opposite to the second surface. 9. The method for manufacturing a double-sided solar cell according to claim 9, wherein after forming the second electrode on the lower surface of the second passivation layer, the method further comprises: Carry out anti-light decay treatment.

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