阅读说明：本技术 一种异质结电池制备方法及异质结电池 (Heterojunction battery and preparation method thereof ) 是由 不公告发明人 于 2021-01-06 设计创作，主要内容包括：本发明提供了一种异质结电池制备方法,包括配置制绒剂,制绒剂包括50±10％碱溶液、水、制绒添加剂；将单晶硅片置于制绒剂内,在单晶片表面生成若干个并列且依次连接的金字塔结构,若干个金字塔结构形成小绒面；在小绒面上依次形成非晶硅层、形成透明导电层；使用银浆原料在透明导电层表面形成主栅线和副栅线。50±10％碱溶液、水、制绒添加剂三者之间的体积比范围为150：10：1～450：30：1；其中,金字塔结构的直径小于银浆原料中50～90％的银颗粒直径。本发明还提供了一种异质结电池。本发明的异质结电池制备方法能够使副栅线的线宽平均窄2.2μm,可以带来约15mA电流的提升。(The invention provides a preparation method of a heterojunction battery, which comprises the steps of preparing a texturing agent, wherein the texturing agent comprises 50 +/-10% of alkaline solution, water and a texturing additive; placing a monocrystalline silicon wafer in a texturing agent, generating a plurality of pyramid structures which are parallel and sequentially connected on the surface of the monocrystalline silicon wafer, and forming a small textured surface by the plurality of pyramid structures; sequentially forming an amorphous silicon layer and a transparent conductive layer on the small suede; and forming a main grid line and an auxiliary grid line on the surface of the transparent conducting layer by using silver paste raw materials. The volume ratio range of 50 +/-10% of alkali solution, water and the wool making additive is 150: 10: 1-450: 30: 1; the diameter of the pyramid structure is smaller than the diameter of 50-90% of silver particles in the silver paste raw material. The invention also provides a heterojunction battery. The heterojunction battery preparation method can enable the line width of the auxiliary grid line to be average narrow by 2.2 mu m, and can improve the current of about 15 mA.)

1. A heterojunction battery preparation method is characterized by comprising the following steps:

preparing a texturing agent, wherein the texturing agent comprises 50 +/-10% of alkali solution, water and a texturing additive;

placing a single crystal silicon wafer in the texture-making agent, generating a plurality of pyramid structures which are parallel and sequentially connected on the surface of the single crystal wafer, and forming a small texture surface by the plurality of pyramid structures;

sequentially forming an amorphous silicon layer and a transparent conducting layer on the small suede;

forming a main grid line and an auxiliary grid line on the surface of the transparent conducting layer by using silver paste raw materials;

wherein the volume ratio range of the 50 +/-10% alkali solution, the water and the wool making additive is 150: 10: 1-450: 30: 1;

the diameter of the pyramid structure is smaller than the diameter of 50-90% of silver particles in the silver paste raw material.

2. The method of claim 1, wherein the volume ratio of the 50 ± 10% alkali solution, the water, and the texturing additive is 300:20: 1.

3. the method of claim 1, wherein the 50 + 10% alkaline solution is a 50 + 10% sodium hydroxide solution or a 50 + 10% potassium hydroxide solution.

4. The method for preparing a heterojunction cell as claimed in claim 1, wherein in the step of placing the single crystal silicon wafer in the texturing agent and generating a plurality of pyramid structures which are connected in parallel and in sequence on the surface of the single crystal wafer: and heating the texturing agent at 85-95 ℃.

5. The method for preparing a heterojunction cell according to claim 1, wherein in the steps of sequentially forming an amorphous silicon layer and a transparent conductive layer on the small textured surface: and forming the amorphous silicon layer by adopting a plasma enhanced chemical vapor deposition method, and forming the transparent conducting layer by adopting a physical vapor deposition method.

6. The preparation method of the heterojunction battery according to claim 1, wherein in the step of forming the main gate line and the auxiliary gate line on the surface of the transparent conductive layer by using silver paste raw materials: and forming the main grid lines and the auxiliary grid lines by adopting a screen printing method, wherein a plurality of main grid lines are parallel to each other, a plurality of auxiliary grid lines are parallel to each other, and the main grid lines and the auxiliary grid lines are arranged vertically.

7. A method for preparing a heterojunction battery according to any of claims 1 to 6, wherein the diameter a of the pyramid structure is 1 to 4 μm.

8. A heterojunction battery preparation method according to any of claims 1 to 6, wherein the width of the secondary grid line is in the range of 44.6 to 50.3 μm.

9. A heterojunction battery is characterized by comprising a small suede surface, wherein the small suede surface is positioned on the surface of a monocrystalline silicon wafer, an amorphous silicon layer and a transparent conducting layer are sequentially processed on the small suede surface, and a main grid line and an auxiliary grid line are processed on the transparent conducting layer;

the diameter a of the pyramid structure is 1-4 μm.

10. The heterojunction cell of claim 9 wherein the width of the subgrids is in the range of 44.6 to 50.3 μm.

Technical Field

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

Background

In the production process of the heterojunction battery, in order to improve the light conversion rate, a small suede is required to be manufactured on the surface of a silicon wafer, then grid lines are manufactured on the small suede, the small suede is used for absorbing solar energy, and the grid lines are used for collecting and transmitting current. The grid lines comprise auxiliary grid lines and main grid lines, the auxiliary grid lines are used for collecting current, the main grid lines are used for conveying current, and therefore the number of the auxiliary grid lines is far larger than that of the main grid lines.

Because the width of the grid line has great influence on the performance of the heterojunction battery, the narrower the line width is, the smaller the shading area of the small suede is, the more the light absorbed by the battery is, and the photo-generated current is increased. Therefore, the smaller the width of the grid line, the more favorable the absorption of solar energy. Therefore, there is a need for an improvement of the existing gate line width optimization method.

Disclosure of Invention

In order to ensure that grid lines for preparing a printing screen are not too thin and broken without increasing the cost, the invention provides a heterojunction battery preparation method, the method can ensure that the grid lines are in proper width, and the heterojunction battery prepared by the method is low in cost and excellent in performance.

The technical scheme for realizing the purpose of the invention is as follows:

the invention provides a preparation method of a heterojunction battery, which comprises the following steps:

preparing a texturing agent, wherein the texturing agent comprises 50 +/-10% of alkali solution, water and a texturing additive;

placing a monocrystalline silicon wafer in a texturing agent, generating a plurality of pyramid structures which are parallel and sequentially connected on the surface of the monocrystalline silicon wafer, and forming a small textured surface by the plurality of pyramid structures;

sequentially forming an amorphous silicon layer and a transparent conductive layer on the small suede;

and forming a main grid line and an auxiliary grid line on the surface of the transparent conducting layer by using silver paste raw materials.

Wherein, the volume ratio range of 50 +/-10% alkali solution, water and the texturing additive is 150: 10: 1-450: 30: 1.

the diameter of the pyramid structure is smaller than the diameter of 50-90% of silver particles in the silver paste raw material.

Generally, a 600:40:1, preparing a texturing agent by using 50 +/-10% alkali solution, water and a texturing additive, wherein the diameter of a pyramid structure of a textured surface generated on the surface of a monocrystalline silicon wafer by the texturing agent is 1-7 mu m. The silver paste raw material comprises about 50% of 1-10 micron silver particles, about 20% of 10-50 micron silver particles and about 10% of nano-scale silver particles. At the moment, silver particles after printing and screen printing can be spread and simultaneously sink into valley bottoms between adjacent pyramid structures, so that the line width of the secondary grid lines is wide, the silver particles which are already spread after annealing are difficult to gather towards the middle, the light absorption area of the battery is reduced, and the photo-generated current is reduced.

The principle of the heterojunction battery preparation method is as follows: the invention improves the existing texturing agent, prepares a new texturing agent (50 +/-10% of alkali solution, water and a texturing additive), and improves three components of the texturing agent, so that the texture surface formed by the monocrystalline silicon wafer is a small texture surface. Meanwhile, the pyramid structure of the small suede is in a micron level, the amorphous silicon layer and the transparent conducting layer are both composed of atoms, the thickness of the amorphous silicon layer and the thickness of the transparent conducting layer are in a nanometer level, and the total thickness of the amorphous silicon layer and the transparent conducting layer is about 90-120 nanometers. When the amorphous silicon layer and the transparent conducting layer cover the pyramid structure, the influence of the amorphous silicon layer and the transparent conducting layer on the diameter of the pyramid structure can be ignored, so that the surface appearance of the monocrystalline silicon wafer before the silk screen is printed is still the original pyramid structure and size.

When the silver paste raw material is printed on the surface of the transparent conductive layer, the diameter of the pyramid structure is reduced due to the fact that the small suede surface is smaller than the normal suede surface, the diameter of the pyramid structure is smaller than the diameter of 50-90% of silver particles in the silver paste raw material, the amount of the silver particles in the silver paste raw material falling into valleys between adjacent pyramid structures is greatly reduced, and a large amount of silver particles are prevented from being dispersed. In the annealing process, the gathering of silver particles is ensured, so that the line width of a printing silk screen is reduced, and the reduction of photo-generated current caused by the reduction of the light absorption area of a battery is avoided.

By optimizing and improving the texture-making agent, a small texture surface is generated on the surface of the monocrystalline silicon wafer, and the small texture surface comprises a plurality of pyramid structures which are arranged in parallel and in sequence. The silver particle amount greatly reduced in the valley bottom that makes between the adjacent pyramid structure that drops at the in-process of printing silk screen printing has guaranteed gathering together of silver particle, and then has reduced the width of vice grid line, avoids the light-absorbing area of battery to reduce and reduce photoproduction electric current.

Further, the volume ratio of the 50 +/-10% alkali solution, the water and the texturing additive is 300:20: 1.

further, the 50 plus or minus 10% alkali solution is 50 plus or minus 10% sodium hydroxide solution or 50 plus or minus 10% potassium hydroxide solution.

Further, in the step of placing the single crystal silicon wafer in the texture etching agent and generating a plurality of pyramid structures which are connected in parallel and in sequence on the surface of the single crystal wafer: the texturing agent is heated, and the heating temperature range is 85-95 ℃.

Further, the steps of forming an amorphous silicon layer and a transparent conductive layer on the small suede in sequence are as follows: and forming an amorphous silicon layer by adopting a plasma enhanced chemical vapor deposition method, and forming a transparent conducting layer by adopting a physical vapor deposition method.

Further, in the step of forming the main gate line and the auxiliary gate line on the surface of the transparent conductive layer by using silver paste raw materials: the method comprises the steps of forming a main grid line and an auxiliary grid line by a screen printing method, wherein the main grid lines are parallel to each other, the auxiliary grid lines are parallel to each other, and the main grid lines and the auxiliary grid lines are arranged perpendicularly.

Furthermore, the diameter a of the pyramid structure is 1-4 μm.

Furthermore, the width range of the secondary grid line is 44.6-50.3 mu m.

The invention also provides a heterojunction battery which comprises a small suede surface, wherein the small suede surface is positioned on the surface of the monocrystalline silicon piece, an amorphous silicon layer and a transparent conducting layer are sequentially processed on the small suede surface, and a main grid line and an auxiliary grid line are processed on the transparent conducting layer. The diameter a of the pyramid structure of the small suede is 1-4 mu m.

Furthermore, the width range of the secondary grid line is 44.6-50.3 mu m.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, the texture-making agent is improved, the small texture surface is prepared on the surface of the monocrystalline silicon, so that the diameter of the pyramid structure is smaller than that of 50-90% of silver particles in the silver paste raw material, the amount of the silver particles which are diffused and fall to the valley bottom of the adjacent pyramid structure is greatly reduced, the silver particles after annealing generate an obvious agglomeration phenomenon, the light absorption area of the heterojunction battery is increased, and the performance of the heterojunction battery is improved.

2. According to statistics, the diameter a of the pyramid structure of the generated small texture surface of the heterojunction battery prepared by the preparation method of the heterojunction battery is 1-4 microns, and is 3-7 microns smaller than that of the pyramid structure of the texture surface prepared by the conventional process (the volume ratio of 50 +/-10% of aqueous alkali to water to texture-making additive is 600:40: 1); meanwhile, the width of the secondary grid line printed by the method is 2.2 mu m narrower than the average line width of the secondary grid line prepared by a conventional process (the volume ratio of 50 +/-10% aqueous alkali to water to the texturing additive is 600:40:1), and the current of about 15mA can be increased.

3. In the heterojunction battery prepared by the heterojunction battery preparation method, the narrowing of the auxiliary grid lines is caused by the natural shrinkage of silver paste, so the quality of the auxiliary grid lines is better, the possibility of grid breaking is lower, the yield of a screen printing working section can be increased, and the manufacturing cost is reduced.

Drawings

In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings used in the description of the embodiment will be briefly introduced below. It should be apparent that the drawings in the following description are only for illustrating the embodiments of the present invention or technical solutions in the prior art more clearly, and that other drawings can be obtained by those skilled in the art without any inventive work.

Fig. 1 is a flow chart of a method of fabricating a heterojunction cell according to an embodiment of the invention;

FIG. 2 is a schematic view of the line width of a printing screen printed on a small suede and a normal suede manufactured by a conventional method in an embodiment of the present invention;

figure 3 is a schematic comparison of a printing screen of a heterojunction cell in an embodiment of the invention with a printing screen of a prior art heterojunction cell;

wherein, 1, monocrystalline silicon slice; 2. a pyramid structure; 3. a secondary gate line; 31. silver particles.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

In the description of the present embodiments, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to a number of indicated technical features. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

Example 1:

for the optimization of the grid line width, the grid line width can be reduced by adopting silver nano slurry or more advanced equipment, but the cost is high, and the prepared grid line is too thin and easily causes the risk of grid line fracture. According to the invention, the number of silver particles with the diameter larger than the size of the pyramid structure in the silver paste raw material for forming the grid line is greatly increased by using the small suede process, so that the number of silver particles falling into the valley bottom of the adjacent pyramid structure is reduced, the silver particles generate an obvious agglomeration phenomenon after annealing, the light absorption area of the heterojunction battery is finally increased, and the performance of the heterojunction battery is improved.

This example provides a method for fabricating a heterojunction cell, and in this embodiment, as shown in fig. 1, fig. 1 is a flow chart of the method for fabricating the heterojunction cell.

A method of fabricating a heterojunction battery, comprising the steps of:

s1, preparing a texturing agent, wherein the texturing agent comprises 50 +/-10% of alkali solution, water and a texturing additive.

In this embodiment, a 50 ± 10% alkali solution, water, and a texturing additive are selected to prepare a texturing agent, wherein the 50 ± 10% alkali solution: water: the volume ratio range of the texturing additive is 150: 10: 1-450: 30: 1, preferably, 50 ± 10% alkali solution: water: the volume ratio of the texturing additive is 300:20: 1.

Specifically, the 50 + -10% alkali solution can be 50 + -10% sodium hydroxide solution or 50 + -10% potassium hydroxide solution.

S2, placing the single crystal silicon wafer in a texturing agent, generating a plurality of pyramid structures which are parallel and sequentially connected on the surface of the single crystal wafer, and forming a small textured surface by the plurality of pyramid structures.

In this embodiment, the texturing agent is heated to 85-95 ℃, and the alkali solution in the texturing agent reacts with the surface of the monocrystalline silicon at 85-95 ℃, so as to corrode the surface of the monocrystalline silicon to prepare a small textured surface with a pyramid structure having an anti-reflection effect.

Specifically, the diameter a of the pyramid structure of the small texture surface of the embodiment is 1 to 4 μm, which is smaller than the diameter (about 1 to 7 μm) of the pyramid of the texture surface generated according to the conventional texture-making agent (the volume ratio of 50 ± 10% alkali solution to water to texture-making additive is 600:40: 1). The texturing agent obtained through optimization is used for texturing the surface of the monocrystalline silicon wafer, so that the cost of the texturing agent is reduced, the diameter of the pyramid structure is reduced, silver particles are greatly reduced and fall to the valley bottoms of the adjacent pyramid structures under the condition that silver paste raw materials are not changed, and the silver particles of the printing silk screen are more easily gathered in the printing process so as to reduce the line width of the printing silk screen.

And S3, sequentially forming an amorphous silicon layer and a transparent conductive layer on the small suede.

Specifically, in this step, the amorphous silicon layer is formed by a plasma enhanced chemical vapor deposition method, and the transparent conductive layer is formed by a physical vapor deposition method.

And S4, forming a main grid line and an auxiliary grid line on the surface of the transparent conducting layer by using silver paste raw materials.

Specifically, the main grid lines and the auxiliary grid lines are formed by a screen printing method, a plurality of main grid lines are parallel to each other, a plurality of auxiliary grid lines are parallel to each other, and the main grid lines and the auxiliary grid lines are arranged perpendicularly.

Specifically, as shown in fig. 2, fig. 2 is a schematic diagram of a line width of a printing screen printed on a small suede of this embodiment and a normal suede manufactured by a conventional method. The width of the secondary grid lines of the present embodiment is 44.6-50.3 μm, which is 2.2 μm narrower on average than the secondary line width (between about 47.8-54.6 μm) generated by the conventional texturing agent (the volume ratio of 50 ± 10% alkali solution to water to texturing additive is 600:40:1) and the printing method, and can increase the current by about 15 mA.

Generally, a 600:40:1, preparing a texturing agent by using 50 +/-10% aqueous alkali, water and a texturing additive, wherein the diameter of a pyramid structure of a textured surface generated on the surface of a monocrystalline silicon wafer by the texturing agent is 1-7 mu m. The silver paste raw material comprises about 50% of 1-10 micron silver particles, about 20% of 10-50 micron silver particles and about 10% of nano-scale silver particles. At the moment, silver particles after printing and screen printing can be spread and simultaneously sink into valley bottoms between adjacent pyramid structures, so that the line width of the secondary grid lines is wide, the silver particles which are already spread after annealing are difficult to gather towards the middle, the light absorption area of the battery is reduced, and the photo-generated current is reduced.

The principle of the heterojunction battery preparation method is as follows: the texture surface formed by the monocrystalline silicon wafer is a small texture surface by improving the texture surface agent, preparing a new texture surface agent (50 +/-10% of alkali solution, water and a texture surface additive), and improving three components of the texture surface agent. Meanwhile, the pyramid structure of the small suede is in a micron level, the amorphous silicon layer and the transparent conducting layer are both composed of atoms, the thickness of the amorphous silicon layer and the thickness of the transparent conducting layer are in a nanometer level, and the total thickness of the amorphous silicon layer and the transparent conducting layer is about 90-120 nanometers. When the amorphous silicon layer and the transparent conducting layer cover the pyramid structure, the influence of the amorphous silicon layer and the transparent conducting layer on the diameter of the pyramid structure can be ignored, so that the surface appearance of the monocrystalline silicon wafer before the silk screen is printed is still the original pyramid structure and size.

In this embodiment, the diameter of the pyramid structure is smaller than 50-90% of the silver particle diameter in the silver paste raw material. When the silver paste raw material is printed on the surface of the transparent conductive layer, the diameter of the pyramid structure is reduced because the small suede is smaller than the normal suede, so that the amount of silver particles in the silver paste raw material falling into valleys between adjacent pyramid structures is greatly reduced, and a large amount of silver particles are prevented from being dispersed. In the annealing process, the gathering of silver particles is ensured, so that the line width of a printing silk screen is reduced, and the reduction of photo-generated current caused by the reduction of the light absorption area of a battery is avoided.

Example 2:

this example provides a heterojunction cell prepared by the method of example 1, as shown in fig. 3, and fig. 3 is a schematic diagram comparing the printing screen of the heterojunction cell of this example with the printing screen of the existing heterojunction cell.

In this embodiment, the heterojunction cell includes a small textured surface, the small textured surface is located on the surface of the monocrystalline silicon wafer 1, an amorphous silicon layer (not shown in the drawings) and a transparent conductive layer (not shown in the drawings) are sequentially processed on the small textured surface, and a main gate line (not shown in the drawings) and an auxiliary gate line 3 are processed on the transparent conductive layer.

In the present embodiment, the amorphous silicon layer is formed by a plasma enhanced chemical vapor deposition method, and the transparent conductive layer is formed by a physical vapor deposition method.

Wherein the diameter a of the pyramid structure 2 of the small suede is 1-4 μm.

Furthermore, the width range of the minor grid line 3 with the small suede is 44.6-50.3 mu m.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.