WO2017113299A1

WO2017113299A1 - Back-contact heterojunction solar cell and preparation method therefor

Info

Publication number: WO2017113299A1
Application number: PCT/CN2015/100133
Authority: WO
Inventors: 薛黎明; 杨武保; 陆钧
Original assignee: 中海阳能源集团股份有限公司
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2017-07-06
Also published as: CN108521832A

Abstract

A back-contact heterojunction solar cell and a preparation method therefor. The back-contact heterojunction solar cell comprises: a crystalline silicon substrate (01), a heterojunction portion (02) and a back-contact portion. A light trapping layer (03) is formed on the front side of the crystalline silicon substrate. An anti-reflection film (04) is deposited on the light trapping layer. The heterojunction portion is located on the back of the crystalline silicon substrate, and comprises an intrinsic amorphous silicon film layer (05), a P-type amorphous silicon film layer (06) and an N-type amorphous silicon film layer (07). A conductive film (08) is deposited on the P-type amorphous silicon film layer and the N-type amorphous silicon film layer. The back-contact portion is deposited on the conductive film. A back contact and a heterojunction are integrated. On the one hand, the advantage that a process for manufacturing a heterojunction cell is relatively simple is achieved, and the shortcoming that a conventional heterojunction cell has a front gate line is overcome; and on the other hand, the advantage that a back contact cell does not have a front gate line is maintained, and the shortcoming that a process for manufacturing a conventional back-contact cell is complex is overcome.

Description

Back electrode heterojunction solar cell and preparation method thereof

Technical field

The invention belongs to the field of new energy, and particularly relates to a back electrode heterojunction solar cell and a preparation method thereof.

Background technique

Crystal silicon battery is the current mainstream product. In order to further improve the photovoltaic efficiency of crystalline silicon battery, a variety of new solar cells based on crystalline silicon cells have been developed. Among them, heterojunction cells and back electrode cells are among the most efficient and most photovoltaic. A new generation of high-efficiency solar cells with market prospects.

In a simple heterojunction cell, the positive and negative electrodes are located on the front and back sides of the crystalline silicon substrate, that is, the front gate line and the back gate line need to be prepared. Although the process is relatively simple, the process accuracy is high, otherwise the product yield is good. It will be greatly reduced; when using a conventional amorphous silicon solar cell process to prepare a heterojunction cell, precise and strict masking means and cleaning control are required; the gate line processing in the heterojunction cell requires the use of professional low-temperature silver paste. It has become the main factor restricting the development of heterojunction cells; finally, the use of front gate lines inevitably reduces photovoltaic efficiency.

Although the simple back electrode battery can be used to prepare the back electrode with the positive and negative electrodes on the back side of the crystalline silicon substrate by diffusion, the manufacturing process is particularly complicated, and the process precision is particularly high, which makes the development of the electrode severely constrained; On the other hand, there are serious pollution discharge problems in the process, and there are few companies that can produce back electrode batteries.

Summary of the invention

The present invention aims to provide a high-efficiency solar cell in which a back electrode heterojunction is integrated and a preparation method thereof.

In order to solve the above problems, the present invention provides a back electrode heterojunction solar cell comprising: a crystalline silicon substrate, a heterojunction portion and a back electrode portion, the front surface of the crystalline silicon substrate is formed with a light trapping layer, and the light trapping layer An anti-reflection film is deposited on the back of the crystalline silicon substrate, and the heterojunction portion includes an intrinsic amorphous silicon film layer, a P-type amorphous silicon film layer and an N-type amorphous silicon film layer. The amorphous silicon film layer is deposited on the back surface of the crystalline silicon substrate, and the P-type amorphous silicon film layer and the N-type amorphous silicon film layer are deposited on the intrinsic amorphous silicon film layer, and the P-type amorphous silicon film layer and the N A conductive film is deposited on the amorphous silicon film layer, and a back electrode portion is deposited on the conductive film.

A back electrode heterojunction solar cell according to the above, wherein the crystalline silicon substrate is a P-type crystalline silicon substrate, an N-type crystalline silicon substrate or an intrinsic crystalline silicon substrate.

A back electrode heterojunction solar cell according to the above aspect, wherein the P-type amorphous silicon film layer comprises a P-type amorphous silicon film line and a P-type amorphous silicon collector film line, and the N-type amorphous silicon film layer comprises N Type amorphous silicon film line and N type amorphous silicon collector film line, P type amorphous silicon collector film line and N type amorphous silicon collector film line respectively and P type amorphous silicon film line and N type amorphous The silicon film line is vertically connected.

According to the above-mentioned back electrode heterojunction solar cell, wherein the P-type amorphous silicon film line or the N-type amorphous silicon film line is pre-designed on the intrinsic amorphous silicon film layer by using a point deposition source or a linear deposition source. The geometric deposition scans form the same film line pattern.

According to the above-described back electrode heterojunction solar cell, wherein the film line pattern comprises a linear type or a curved type, and the film line pattern is unequal in width, the closer the film line pattern is to the collector film line, the larger the width.

According to the above-described back electrode heterojunction solar cell, wherein the P-type amorphous silicon collector film line and the N-type amorphous silicon collector film line are respectively distributed on both sides of the intrinsic amorphous silicon film layer on the crystalline silicon substrate A first electrode lead region and a second electrode lead region are formed on the conductive film on the P-type amorphous silicon film layer and the N-type amorphous silicon film layer, respectively.

A back electrode heterojunction solar cell according to the above aspect, wherein the back electrode portion comprises a positive electrode lead and a negative electrode lead, wherein the positive electrode lead is located at the first electrode lead region and the negative electrode lead is located at the second electrode lead region, or The electrode lead is located in the second electrode lead region and the negative electrode lead is located in the first electrode lead region.

The invention provides a preparation method of a back electrode heterojunction solar cell, comprising the following steps:

Step one: performing a texturing process on the front side of the crystalline silicon substrate by using an etching technique to prepare a light trapping layer;

Step 2: depositing an antireflection film on the light trap layer by PVD, CVD or surface oxidation treatment;

Step 3: on the back side of the crystalline silicon substrate, first depositing an intrinsic amorphous silicon film layer by PECVD;

Step 4: depositing a P-type amorphous silicon film layer and the N-type amorphous silicon film layer respectively on the intrinsic amorphous silicon film layer by using a point deposition source or a linear deposition source according to a pre-designed geometric pattern, wherein a P-type amorphous silicon film layer and an N-type amorphous silicon film layer are deposited on the intrinsic amorphous silicon film layer, such that the intrinsic amorphous silicon film layer, the P-type amorphous silicon film layer, and the N-type amorphous silicon The film layer forms a heterojunction portion;

Step 5: depositing a conductive film on the P-type amorphous silicon film layer and the N-type amorphous silicon film layer respectively by using a point deposition source or a linear deposition source;

Step 6: depositing a back electrode portion on the conductive film of the P-type amorphous silicon film layer and the N-type amorphous silicon film layer.

According to the above method for preparing a back electrode heterojunction solar cell, wherein the spot deposition source is deposited on the surface of the intrinsic amorphous silicon film layer, the P-type amorphous silicon film layer or the N-type amorphous silicon film layer A desired film line pattern with linear features.

According to the above method for preparing a back electrode heterojunction solar cell, wherein the spot deposition source is formed by using an electron beam, an ion beam, a laser beam or a micro heat source, and then the reaction material is evaporated by a linear scanning method. The reaction gas or directly ionizes the reaction gas and obtains a film material deposited to a corresponding position to form a point deposition source film layer, and the width of the spot deposition source film layer varies from micrometer to millimeter.

According to the above method for preparing a back electrode heterojunction solar cell, wherein the linear deposition source realizes a desired single linear thin film pattern by a fixed crystalline silicon substrate under a fixed condition, and the linear deposition source passes the moving crystal under a fixed condition. The silicon substrate achieves the desired multi-linear film pattern.

According to the above method for preparing a back electrode heterojunction solar cell, wherein the linear deposition source is formed by using an electron beam, an ion beam, a plasma beam or a fine heat source, and then, the reaction is performed while the linear deposition source is fixed. The reaction gas generated after evaporation of the material or directly ionizes the reaction gas and obtains a film material deposited to a corresponding position to form a linear deposition source film layer, and the width of the linear deposition source film layer varies from micrometer to millimeter.

According to the above method for preparing a back electrode heterojunction solar cell, the process conditions for forming a point deposition source film layer and a linear deposition source to form a linear deposition source film layer include a point deposition source or a linear deposition source. Working pressure, output energy density, ion energy, ion composition, and spacing of the point deposition source from the crystalline silicon substrate;

Among them, the working pressure range is 0.1Pa-10kPa, the output energy density ranges from 1mW/cm ² -1W/mm ² , the particle energy range is 100k-10 ⁴ k, and the particle composition is required for film deposition including Si, N, a matching particle of B, H and Ar, the distance between the point deposition source and the crystalline silicon substrate is not more than 1 m;

Among them, the smaller the kinetic energy component of the particle energy is, the better it is to reduce the impact of the particle on the surface of the substrate, and the point deposition source is away from the crystalline silicon substrate without affecting the condition that the working gas is well mixed and uniformly distributed on the surface of the substrate. The smaller the pitch, the more favorable the formation of the dot-like deposition source film layer.

According to the above method for preparing a back electrode heterojunction solar cell, in the process of depositing the intrinsic amorphous silicon film, the working gas comprises hydrogen, silane and argon, and the flow ratio of hydrogen, silane and argon is: 100: (1-20): (0-100), the working pressure of the working gas is 0.1 Pa-10 kPa.

According to the above method for preparing a back electrode heterojunction solar cell, in which a P-type amorphous silicon film layer and an N-type amorphous silicon film layer are deposited by a point deposition source or a linear deposition source, the working gas includes hydrogen gas. , silane, argon and doping gas, the doping gas comprises borane and / or phosphine, wherein the flow ratio of hydrogen, silane and argon is: 100: (1-20): (0-100), doped The flow ratio of the heterogas to the silane is (0.1-10):100, and the working pressure of the working gas is 0.1 Pa-10 kPa.

Beneficial effect

The invention discloses a back electrode heterojunction solar cell and a preparation method thereof, and the back electrode heterojunction is integrated to have a back electrode with positive and negative electrodes on the back side of the crystalline silicon substrate, and has a heterojunction. The preparation of the back electrode is realized by the method of coating and printing, so that on the one hand, the process of manufacturing the heterojunction cell is simple, the disadvantage of the conventional heterojunction cell having the front gate line is overcome; on the other hand, the back electrode is maintained. The battery has no advantage of the front gate line, and overcomes the disadvantages of the complicated manufacturing process of the conventional back electrode battery.

DRAWINGS

1 is a cross-sectional view of a back electrode heterojunction solar cell disclosed in the present invention;

2 is a schematic view showing a film line pattern of a P-type amorphous silicon film line and an N-type amorphous silicon film line on an intrinsic amorphous silicon film layer of a back electrode heterojunction solar cell according to the present invention;

3 is a schematic diagram of a film line pattern of a P-type amorphous silicon film line and an N-type amorphous silicon film line on another intrinsic amorphous silicon film layer of a back electrode heterojunction solar cell according to the present invention;

4 is a schematic diagram of a film line pattern of a P-type amorphous silicon film line and an N-type amorphous silicon film line on another intrinsic amorphous silicon film layer of a back electrode heterojunction solar cell according to the present invention.

detailed description

The invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

1 is a cross-sectional view of a back electrode heterojunction solar cell disclosed in the present invention. As shown in FIG. 1, the present invention provides a back electrode heterojunction solar cell including: crystalline silicon. a substrate 01, a heterojunction portion 02 and a back electrode portion (not shown), a front surface of the crystalline silicon substrate 01 is formed with a light trapping layer 03, and an antireflection film 04 is deposited on the light trapping layer 03, a heterojunction The portion 02 is located on the back of the crystalline silicon substrate 01, and the heterojunction portion 02 includes an intrinsic amorphous silicon film layer 05, a P-type amorphous silicon film layer 06, and an N-type amorphous silicon film layer 07, an intrinsic amorphous silicon film. The layer 05 is deposited on the back surface of the crystalline silicon substrate 01, and the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07 are intermittently deposited on the intrinsic amorphous silicon film layer 05, and the P-type amorphous silicon film layer 06 A conductive film 08 is deposited on the N-type amorphous silicon film layer 07, and a back electrode portion is deposited on the conductive film 08.

The invention further discloses a back electrode heterojunction solar cell, wherein the crystalline silicon substrate 01 is a P-type crystalline silicon substrate, an N-type crystalline silicon substrate or an intrinsic crystalline silicon substrate, when the crystalline silicon substrate When the 01 is an intrinsic type crystalline silicon substrate, the heterojunction portion 02 may not include the intrinsic amorphous silicon film layer 05, that is, the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07 may be directly The spacer is deposited on an intrinsic crystalline silicon substrate.

2, 3 and 4 are respectively a P-type amorphous silicon film line and an N-type amorphous silicon film line on three intrinsic amorphous silicon film layers of a back electrode heterojunction solar cell disclosed in the present invention. A schematic diagram of a film line pattern, as shown in FIG. 2, FIG. 3 and FIG. 4, according to the above-mentioned back electrode heterojunction solar cell, wherein the P-type amorphous silicon film layer 06 comprises a P-type amorphous silicon film line 09 and P The amorphous silicon collector film line 10 and the N-type amorphous silicon film layer 07 include an N-type amorphous silicon film line 11 and an N-type amorphous silicon collector film line 12, and a P-type amorphous silicon collector film line 10 The N-type amorphous silicon collector film line 12 is vertically connected to the P-type amorphous silicon film line 09 and the N-type amorphous silicon film line 11, respectively.

As shown in FIG. 2, FIG. 3 and FIG. 4, according to the above-described back electrode heterojunction solar cell, wherein the P-type amorphous silicon film line 09 or the N-type amorphous silicon film line 11 utilizes a point deposition source Or a linear deposition source is formed on the intrinsic amorphous silicon film layer 05 by a pre-designed geometric pattern to form the same film line pattern. Further, the film line pattern includes a straight line or a curved line, and the width of the film line pattern may be equal. For example, the film line patterns shown in FIG. 1 and FIG. 2 may be unequal, and the linear film line pattern widths may not be equal, for example, may be triangles, and the linear film line pattern widths may not be equal, for example, as shown in FIG. The film line pattern, when the width of the film line pattern is not equal, the closer the film line pattern is to the collector film line, the larger the width, such a design is advantageous for obtaining maximum photovoltaic efficiency.

According to the above-described back electrode heterojunction solar cell, wherein the P-type amorphous silicon collector film line 10 and the N-type amorphous silicon collector film line 12 are respectively distributed on the crystalline silicon substrate 01, the intrinsic amorphous silicon The first electrode lead region and the second electrode lead region (not shown) are formed on both sides of the film layer 05 on the conductive film 08 on the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07, respectively. .

A back electrode heterojunction solar cell according to the above aspect, wherein the back electrode portion comprises a positive electrode lead and a negative electrode lead, wherein the positive electrode lead is located at the first electrode lead region and the negative electrode lead is located at the second electrode lead region, or The electrode lead is located in the second electrode lead region and the negative electrode lead is located in the first electrode lead region (not shown).

Step 1: the surface of the crystalline silicon substrate 01 is subjected to a texturing process using an etching technique to prepare a light trapping layer 03;

Step 2: depositing an anti-reflection film 04 on the light trap layer 03 by PVD, CVD or surface oxidation treatment;

Step 3: on the back side of the crystalline silicon substrate 01, first depositing an intrinsic amorphous silicon film layer 05 by PECVD;

Step 4: depositing a P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer on the intrinsic amorphous silicon film layer 05 by using a point deposition source or a linear deposition source according to a pre-designed geometry. 07, wherein a P-type amorphous silicon film layer 06 and an N-type amorphous silicon film layer 07 are intermittently deposited on the intrinsic amorphous silicon film layer 05, such that the intrinsic amorphous silicon film layer 05, the P-type amorphous silicon film Layer 06 and N-type amorphous silicon film layer 07 form a heterojunction portion 05;

Step 5: depositing a conductive film 08 on the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07 by using a point deposition source or a linear deposition source;

Step 6: depositing a back electrode portion on the conductive film 08 of the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07.

According to the above-described back electrode heterojunction solar cell, wherein the spot deposition source is deposited on the surface of the intrinsic amorphous silicon film layer 05, the P-type amorphous silicon film layer 06 or the N-type amorphous silicon film layer 07 A desired film line pattern with linear features.

According to the above-mentioned back electrode heterojunction solar cell, wherein the spot deposition source is formed by using an electron beam, an ion beam, a laser beam or a fine heat source, and then the reaction gas generated by evaporating the reaction material by linear scanning is used. Alternatively, the reaction gas is directly ionized and the film material is deposited to a corresponding position to form a dot-like deposition source film layer having a width ranging from micrometer to millimeter.

According to the above-described back electrode heterojunction solar cell, wherein the linear deposition source realizes the desired single linear film pattern by fixing the crystalline silicon substrate 01 under fixed conditions, and linear The deposition source achieves the desired multi-linear film pattern by moving the crystalline silicon substrate 01 under fixed conditions.

According to the above-mentioned back electrode heterojunction solar cell, wherein the linear deposition source is formed by using an electron beam, an ion beam, a plasma beam or a micro heat source, and then, after the linear deposition source is fixed, the reaction material is evaporated. The generated reaction gas or directly ionizes the reaction gas and obtains a film material deposited to a corresponding position to form a linear deposition source film layer, and the width of the linear deposition source film layer varies from micrometer to millimeter.

According to the above-described back electrode heterojunction solar cell, the process conditions for forming a point deposition source film layer and a linear deposition source to form a linear deposition source film layer include a working pressure of a point deposition source or a linear deposition source. , the output energy density, the ion energy, the ion composition, and the distance between the point deposition source and the crystalline silicon substrate 01;

Among them, the working pressure range is 0.1Pa-10kPa, the output energy density ranges from 1mW/cm ² -1W/mm ² , the particle energy range is 100k-10 ⁴ k, and the particle composition is required for film deposition including Si, N, a matching particle of B, H and Ar, the distance between the spot deposition source and the crystalline silicon substrate 01 is not more than 1 m;

Among them, the smaller the kinetic energy component of the particle energy is, the better it is to reduce the impact of the particle on the surface of the substrate, and the point-like deposition source is away from the crystalline silicon substrate 01 without affecting the full mixing and distribution of the working gas on the surface of the substrate. The smaller the pitch, the more favorable the formation of the dot-like deposition source film layer.

According to the above-mentioned back electrode heterojunction solar cell, in the process of depositing the intrinsic amorphous silicon film layer 05, the working gas includes hydrogen, silane and argon, hydrogen, silane and argon. The gas flow ratio is: 100: (1-20): (0-100), and the working gas has a working pressure of 0.1 Pa-10 kPa.

According to the above-described back electrode heterojunction solar cell, in the process of depositing the P-type amorphous silicon film layer 06 and the N-type amorphous silicon film layer 07 by using a point deposition source or a linear deposition source, the working gas includes hydrogen gas, Silane, argon and doping gas, the doping gas comprises borane and/or phosphine, wherein the flow ratio of hydrogen, silane and argon is: 100: (1-20): (0-100), doping The flow ratio of gas to silane is (0.1-10):100, and the working pressure of the working gas is 0.1 Pa-10 kPa.

Embodiment 1:

The N-type crystalline silicon substrate is subjected to a velvet treatment to obtain a light-trapping layer, and on the surface of the velvet-treated surface, an anti-reflection film is deposited by a vacuum coating technique. The antireflection film may be MgF ₂ , SiO ₂ or SiC.

The intrinsic amorphous silicon film layer is deposited by PECVD on the back surface of the crystalline silicon substrate. A P-type amorphous silicon film line was obtained by linear scanning deposition using an electron gun with a focused spot of 1000 μm on the surface on which the intrinsic amorphous silicon film layer was deposited. The pitch between the P-type amorphous silicon film lines was 1060 μm, and the line head of the P-type amorphous silicon film line was 3.2 mm from the edge of the crystalline silicon substrate.

Using a 3 mm electron beam source with a spotted spot, perpendicular to the P-type amorphous silicon film line and 0.2 mm from the edge of the crystalline silicon substrate, a P-type amorphous silicon collector film line thicker than the P-type amorphous silicon film is deposited. The P-type amorphous silicon collector film line is in communication with the front P-type amorphous silicon film line to form a P-type amorphous silicon film layer.

The N-type amorphous silicon film line is deposited by the same method, wherein the distance between the N-type amorphous silicon film line and the P-type amorphous silicon film line is 30 micrometers, and the N-type amorphous silicon collector film line is located relative to the P-type The other side of the crystalline silicon substrate of the amorphous silicon collector film line is in communication with all of the N-type amorphous silicon film lines to form a linear N-type amorphous silicon film layer.

On the surface of the P-type amorphous silicon film layer and the N-type amorphous silicon film layer, the electron beam source is also used to deposit the conductive film because the previous N-type amorphous silicon collector film line is located relative to the P-type amorphous silicon collector electrode. The other side of the crystalline silicon substrate of the film line, therefore, the first electrode lead region and the second electrode lead region are respectively formed on the conductive film of the P-type amorphous silicon collector film line and the N-type amorphous silicon collector film line Finally, a positive electrode lead and a negative electrode lead are respectively deposited in the above two electrode lead regions to form a back electrode portion, and thus the back electrode heterojunction solar cell of the present invention is obtained.

In addition, the material of the conductive film may be Ag. In this case, the conductive film may be directly used as a positive electrode lead and a negative electrode lead of the back electrode portion, and when the conductive film is present, the internal resistance of the battery may be reduced, which is advantageous for improvement. Photovoltaic performance.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical solution of the present invention in any way. Any simple modifications, form changes and modifications of the above embodiments in accordance with the technical spirit of the present invention fall within the scope of the present invention.

Claims

A back electrode heterojunction solar cell, characterized in that: the solar cell comprises: a crystalline silicon substrate, a heterojunction portion and a back electrode portion, the front surface of the crystalline silicon substrate is formed with a light trapping layer, An antireflection film is deposited on the light trap layer, the heterojunction portion is located at a back of the crystalline silicon substrate, and the heterojunction portion includes an intrinsic amorphous silicon film layer, a P type amorphous silicon film layer, and N a type of amorphous silicon film layer deposited on a back surface of the crystalline silicon substrate, the P-type amorphous silicon film layer and the N-type amorphous silicon film layer being deposited at intervals A conductive film is deposited on the intrinsic amorphous silicon film layer, and the P-type amorphous silicon film layer and the N-type amorphous silicon film layer, and the back electrode portion is deposited on the conductive film.
A back electrode heterojunction solar cell according to claim 1, wherein the crystalline silicon substrate is a P-type crystalline silicon substrate, an N-type crystalline silicon substrate or an intrinsic crystalline silicon substrate.
The back electrode heterojunction solar cell according to claim 1, wherein the P-type amorphous silicon film layer comprises a P-type amorphous silicon film line and a P-type amorphous silicon collector film line, and The N-type amorphous silicon film layer includes an N-type amorphous silicon film line and an N-type amorphous silicon collector film line, the P-type amorphous silicon collector film line and the N-type amorphous silicon collector film The lines are vertically connected to the P-type amorphous silicon film line and the N-type amorphous silicon film line, respectively.
The back electrode heterojunction solar cell according to claim 3, wherein the P-type amorphous silicon film line or the N-type amorphous silicon film line is formed by a point deposition source or a linear deposition source. The intrinsic amorphous silicon film layer is deposited by pre-designed geometry to form the same film line pattern.
The back electrode heterojunction solar cell according to claim 4, wherein the film line pattern comprises a linear type or a curved type, and the film line pattern is closer to the collector when the film line pattern width is not equal The film line has a larger width.
The back electrode heterojunction solar cell according to claim 3, wherein the P-type amorphous silicon collector film line and the N-type amorphous silicon collector film line are respectively distributed in the crystal The first electrode lead region and the second electrode lead region are formed on both sides of the intrinsic amorphous silicon film layer on the silicon substrate on the conductive film on the P-type amorphous silicon film layer and the N-type amorphous silicon film layer, respectively.
A back electrode heterojunction solar cell according to claim 1, wherein said back electrode portion comprises a positive electrode lead and a negative electrode lead, wherein said positive electrode lead is located in said first electrode lead region and said The negative electrode lead is located in the second electrode lead region, or the positive electrode lead is located in the second electrode lead region and the negative electrode lead is located in the first electrode lead region.
A method for preparing a back electrode heterojunction solar cell, characterized in that the method comprises the following steps:

Step one: performing a texturing process on the front side of the crystalline silicon substrate by using an etching technique to prepare a light trapping layer;

Step 2: depositing an antireflection film on the light trap layer by PVD, CVD or surface oxidation treatment;

Step 3: on the back side of the crystalline silicon substrate, first depositing an intrinsic amorphous silicon film layer by PECVD;

Step 4: depositing a P-type amorphous silicon film layer and the N-type amorphous silicon film layer respectively on the intrinsic amorphous silicon film layer by using a point deposition source or a linear deposition source according to a pre-designed geometric pattern, wherein a P-type amorphous silicon film layer and an N-type amorphous silicon film layer are deposited on the intrinsic amorphous silicon film layer, such that the intrinsic amorphous silicon film layer, the P-type amorphous silicon film layer, and the N-type amorphous silicon The film layer forms a heterojunction portion;

Step 5: depositing a conductive film on the P-type amorphous silicon film layer and the N-type amorphous silicon film layer respectively by using a point deposition source or a linear deposition source;

Step 6: depositing a back electrode portion on the conductive film of the P-type amorphous silicon film layer and the N-type amorphous silicon film layer.
The method for preparing a back electrode heterojunction solar cell according to claim 8, wherein the spot deposition source is in an intrinsic amorphous silicon film layer, a P-type amorphous silicon film layer or an N-type non- Surface scanning deposition of the crystalline silicon film layer achieves the desired film line pattern with linear features.
The method for preparing a back electrode heterojunction solar cell according to claim 9, wherein the point deposition source is formed by using an electron beam, an ion beam, a laser beam or a micro heat source, and then linearly scanning a method of ionizing a reaction gas generated by evaporation of a reaction material or directly ionizing the reaction gas and obtaining a film material deposited to a corresponding position to form a point deposition source film layer having a width of a micron-sized layer Change to the millimeter range.
The method for preparing a back electrode heterojunction solar cell according to claim 8, wherein the linear deposition source passes through the fixed crystalline silicon substrate under fixed conditions. A desired single linear film pattern is achieved, and the linear deposition source achieves the desired multi-linear film pattern by moving the crystalline silicon substrate under fixed conditions.
The method for preparing a back electrode heterojunction solar cell according to claim 11, wherein the linear deposition source is formed by using an electron beam, an ion beam, a plasma beam or a micro heat source, and then linearly The deposition source is fixed, the reaction gas generated by evaporation of the reaction material or directly ionized the reaction gas and the film material is deposited to a corresponding position to form a linear deposition source film layer, and the width of the linear deposition source film layer is It varies from micron to millimeter.
The method for preparing a back electrode heterojunction solar cell according to claim 8, wherein the point deposition source forms a point deposition source film layer and the linear deposition source forms a linear deposition source film layer The process conditions include the working pressure of the point deposition source or the linear deposition source, the energy density of the output, the ion energy, the ion composition, and the distance between the point deposition source and the crystalline silicon substrate;

Wherein, the working pressure ranges from 0.1 Pa to 10 kPa, the output energy density ranges from 1 mW/cm 2 to 1 W/mm 2 , and the particle energy ranges from 100 k to 10 4 k, and the particle composition is required for film deposition. a composite particle comprising Si, N, B, H and Ar, the point deposition source is spaced apart from the crystalline silicon substrate by no more than 1 m;

Wherein, the smaller the kinetic energy component of the particle energy is, the more favorable the particle impact on the surface of the substrate is, and the point-like deposition source is away from the crystalline silicon base without affecting the condition that the working gas is well mixed and uniformly distributed on the surface of the substrate. The smaller the pitch of the sheets, the more favorable the formation of the dot-like deposition source film layer.
The method for preparing a back electrode heterojunction solar cell according to claim 8, wherein during the deposition of the intrinsic amorphous silicon film, the working gas comprises hydrogen, silane and argon, hydrogen, silane and The flow ratio of argon gas is: 100: (1-20): (0-100), and the working pressure of the above working gas is 0.1 Pa-10 kPa.
The method for preparing a back electrode heterojunction solar cell according to claim 8, wherein the P-type amorphous silicon film layer and the deposition layer are deposited by using the spot deposition source or the linear deposition source In the process of the N-type amorphous silicon film layer, the working gas includes hydrogen, silane, argon gas and doping gas, and the doping gas includes borane and/or phosphane, wherein the flow ratio of hydrogen, silane and argon It is: 100: (1-20): (0-100), the flow ratio of the doping gas to the silane is (0.1-10): 100, and the working pressure of the above working gas is 0.1 Pa-10 kPa.