Solar cell metal electrode microstructure and preparation method thereof

Abstract

The invention belongs to the technical field of solar cell metal electrodes, and particularly relates to a solar cell metal electrode microstructure and a preparation method thereof, and the microstructure comprises a solar cell epitaxial structure, a metal electrode and an ARC antireflection film. The triangular contact layer is arranged on the surface of the solar cell, the triangular contact layer is triangular, the metal electrode covers the surface above the triangular contact layer, and the ARC antireflection film is a film covering the upper surfaces of the solar cell and the metal electrode; a base angle alpha, close to the solar cell, of the triangular contact layer is greater than 45 degrees; the shape of the triangular contact layer can be set to be an acute triangle, two base angles of the acute triangle are both larger than 45 degrees, the triangular contact layer can also be set to be an isosceles triangle, and the base angles of the isosceles triangle are both larger than 45 degrees. The microstructure designed by the invention can project all incident light into the solar cell, and meanwhile, a corresponding preparation process is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cell metal electrodes, and in particular relates to a solar cell metal electrode microstructure and a preparation method thereof. Background Art

[0002] Since the birth of the first solar cell in 1954, the world has launched an unprecedented research enthusiasm for the utilization of this clean energy. To date, solar cells have achieved higher efficiency through the use of multi-junction, tunnel junction, gate electrode and ARC film. The efficiency of non-concentrating cells has reached nearly 40%, and the efficiency of concentrating cells has reached nearly 50%.

[0003] Problems with existing technologies: Bottlenecks have been reached in material systems and the design of solar cell concentration processes. When incident light hits the metal surface, traditional metal electrodes are prone to loss of incident light due to reflection. In addition, the installation of traditional metal electrodes will also occupy the light absorption area on the surface of the solar cell, making it impossible to improve the efficiency of the concentrating cell. Summary of the invention

[0004] The purpose of the present invention is to provide a solar cell metal electrode microstructure and a preparation method thereof, which can project all incident light into the interior of the solar cell and simultaneously provide a corresponding preparation process.

[0005] The technical solution adopted by the present invention is as follows: A solar cell metal electrode microstructure, comprising: Solar cell epitaxial structure, metal electrodes and ARC antireflection film; The solar cell epitaxial structure comprises a solar cell and a contact layer; The surface of the epitaxial structure of the solar cell facing away from the side of the silicon wafer processing operation is provided with a contact layer, and the surface of the solar cell is provided with a triangular contact layer, and the triangular contact layer is triangular; The metal electrode covers the surface above the triangular contact layer; The ARC anti-reflection film is a film covering the upper surface of the solar cell and the metal electrode.

[0006] The solar cell is a flip-chip cell, and also includes a single-junction cell or a multi-junction cell.

[0007] The base angle α of the triangular contact layer close to the solar cell is greater than 45 degrees.

[0008] The angles of the triangular contact layer close to two bottom corners of the solar cell are equal or different.

[0009] The contact layer is etched to form a window layer with a depth reaching the surface of the solar cell.

[0010] The bottom angle of the metal electrode with the strip-shaped ridge morphology is in a non-contact splicing relationship with the surface of the solar cell, and there is a gap between the bottom edge of the metal electrode and the surface of the solar cell.

[0011] The ARC antireflection film is in direct contact with the surface of the solar cell and the surface of the metal electrode.

[0012] A method for preparing a metal electrode microstructure of a solar cell is as follows: Step 1: Provide a flip-chip solar cell epitaxial wafer, electroplate copper metal on the cell epitaxial wafer, evaporate the metal electrode, and then bond the silicon wafer on it; Step 2: Use a mixed solution of ammonia and hydrogen peroxide to etch the substrate to the contact layer in the epitaxial structure and deposit a silicon oxide mask layer; Step 3: After photoresist is evenly coated on the surface of the silicon wafer, a triangular mask is formed through exposure, development, reflow and other operations; Step 4: Place the sample in ICP and use etching to form a triangular silicon dioxide mask shape. The silicon dioxide mask is triangular and the bottom angle is greater than 45 degrees. Step 5: Use ICP etching to transfer the triangular silicon dioxide mask shape to the contact layer, and the etching depth reaches the first window layer after the battery contact layer. Deposit a photoresist mask layer on the contact layer again to form a triangular contact layer morphology; Step 6: Place a metal electrode on the triangular contact layer shape, and then deposit the ARC anti-reflection film on the cell surface to form a complete solar cell chip.

[0013] The technical effects achieved by the present invention are: The present invention designs a triangular electrode with a bottom angle α greater than 45°. When incident light is incident on the surface of the metal electrode, the light is reflected and incident into the interior of the solar cell, effectively reducing the incident light loss caused by reflection of the traditional metal electrode, further improving the conversion efficiency of the cell, and the ARC anti-reflection film is provided to prevent the solar cell surface from reflecting sunlight, thereby improving the absorption of sunlight by resisting reflection. The microstructure of the present design can project all the incident light into the interior of the solar cell, effectively increasing the short-circuit current of the cell, improving the utilization rate of the incident light, and increasing the output power.

[0014] The present invention provides a method for preparing a battery microstructure with a metal electrode having a strip-shaped ridge morphology, and provides a battery preparation process capable of improving the utilization rate of incident light. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of preparing a solar cell epitaxial wafer provided by an embodiment of the present invention; Figure 2 is a diagram of a triangular battery contact layer formed by an embodiment of the present invention; Figure 3 is a schematic diagram of depositing a metal electrode on a triangular contact layer according to an embodiment of the present invention; Figure 4 is a schematic diagram of depositing an ARC film on the surface of a solar cell according to an embodiment of the present invention; Figure 5 is a top view of a metal electrode in an embodiment of the present invention.

[0016] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Solar cell epitaxial structure; 101. Solar cell; 102. Contact layer; 103. Triangular contact layer; 104. Window layer; 2. Metal electrode; 3. ARC antireflection film. DETAILED DESCRIPTION

[0017] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0018] like Figure 1-Figure 5 As shown, a solar cell metal electrode microstructure includes a solar cell epitaxial structure 1, a metal electrode 2 and an ARC antireflection film 3; See attached Figure 1 The solar cell epitaxial structure 1 includes a solar cell 101 and a contact layer 102. The surface of the epitaxial wafer of the solar cell 101 is electroplated, evaporated and bonded, and a silicon wafer is bonded thereon. After the surface of the silicon wafer is evenly coated with photoresist, a triangular mask is formed through exposure, development, reflow and other operations. The solar cell 101 is a flip-chip cell, and also includes a single-junction cell or a multi-junction cell.

[0019] See attached Figure 1-Figure 5 A contact layer 102 is provided on the epitaxial structure surface of the solar cell 101 away from the side where the silicon wafer is processed. A triangular contact layer 103 is provided on the surface of the solar cell 101. The triangular contact layer 103 is triangular in shape. The base angle α of the triangular contact layer 103 close to the solar cell 101 is greater than 45 degrees. The angles of the two base angles of the triangular contact layer 103 close to the solar cell 101 are equal or different. Therefore, the shape of the triangular contact layer 103 can be set to an acute triangle, and the two base angles are greater than 45 degrees, and can also be set to an isosceles triangle, and the base angles are all greater than 45 degrees.

[0020] See attached Figure 2 The contact layer 102 is etched to form a window layer 104 with a depth reaching the surface of the solar cell 101 .

[0021] See attached Figure 3-Figure 5 The metal electrode 2 covers the surface above the triangular contact layer 103 , the bottom angle of the metal electrode 2 with a strip ridge morphology is in a non-contact splicing relationship with the surface of the solar cell 101 , and there is a gap between the bottom edge of the metal electrode 2 and the surface of the solar cell 101 .

[0022] See attached Figure 4 The ARC anti-reflection film 3 is a film covering the upper surface of the solar cell 101 and the metal electrode 2. The ARC anti-reflection film 3 and the surface of the solar cell 101 and the surface of the metal electrode 2 are in direct contact with each other.

[0023] According to the above structure, a triangular electrode with a bottom angle α greater than 45° is designed. When the incident light is incident on the surface of the metal electrode 2, the light is reflected and incident into the interior of the finished solar cell, which effectively solves the incident light loss caused by the reflection of the traditional metal electrode 2 and further improves the conversion efficiency of the cell. The ARC anti-reflection film 3 is set to avoid the situation where the surface of the solar cell 101 reflects sunlight, and improves the absorption of sunlight by resisting reflection. The microstructure of this design can project all the incident light into the interior of the solar cell 101, which can effectively increase the short-circuit current of the battery, improve the utilization rate of the incident light, and increase the output power.

[0024] The working principle of the present invention is as follows: an isosceles triangle electrode with a base angle α greater than 45° is designed, and when incident light is incident on the surface of the metal electrode 2, the light is reflected and incident into the interior of the finished solar cell.

[0025] A method for preparing a metal electrode microstructure of a solar cell is as follows: Step 1: Provide a flip-chip solar cell 101 epitaxial wafer, electroplate copper metal on the cell epitaxial wafer, evaporate the metal electrode, and then bond the silicon wafer on it; Step 2: using a mixed solution of ammonia and hydrogen peroxide to etch the substrate to the contact layer 102 in the epitaxial structure, and depositing a silicon oxide mask layer; Step 3: After photoresist is evenly coated on the surface of the silicon wafer, a triangular mask is formed through exposure, development, reflow and other operations; Step 4: Place the sample in ICP and use etching to form a triangular silicon dioxide mask shape. The silicon dioxide mask is triangular and the bottom angle is greater than 45 degrees. Step 5: Use ICP etching to transfer the triangular silicon dioxide mask shape to the contact layer 102, and the etching depth reaches the first window layer 104 behind the battery contact layer. Deposit a photoresist mask layer on the contact layer again to form a triangular contact layer 103 morphology; Step 6: Place a metal electrode 2 on the triangular contact layer 103, and then deposit an ARC anti-reflection film 3 on the cell surface to form a complete solar cell chip.

[0026] This method provides a method for preparing a battery microstructure having a metal electrode 2 with a strip-shaped ridge morphology.

[0027] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A solar cell metal electrode microstructure, characterized in that: include: Solar cell epitaxial structure (1), metal electrode (2) and ARC antireflection film (3); The solar cell epitaxial structure (1) comprises a solar cell (101) and a contact layer (102); The surface of the epitaxial structure of the solar cell (101) which is away from the side where the silicon wafer is processed is provided with a contact layer (102), and the surface of the solar cell (101) is provided with a triangular contact layer (103), and the triangular contact layer (103) is in the shape of a triangle; The metal electrode (2) covers the surface above the triangular contact layer (103); The ARC anti-reflection film (3) is a film covering the upper surface of the solar cell (101) and the metal electrode (2).

2. A solar cell metal electrode microstructure according to claim 1, characterized in that: The solar cell (101) is a flip-chip cell, and also includes a single-junction cell or a multi-junction cell.

3. The solar cell metal electrode microstructure according to claim 1, characterized in that: The bottom angle α of the triangular contact layer (103) close to the solar cell (101) is greater than 45 degrees.

4. A solar cell metal electrode microstructure according to claim 4, characterized in that: The angles of the two bottom corners of the triangular contact layer (103) close to the solar cell (101) are equal or different.

5. The solar cell metal electrode microstructure according to claim 1, characterized in that: The contact layer (102) is etched to form a window layer (104) with a depth reaching the surface of the solar cell (101).

6. The solar cell metal electrode microstructure according to claim 1, characterized in that: The bottom angle of the metal electrode (2) with a strip-shaped ridge morphology is in a non-contact splicing relationship with the surface of the solar cell (101), and there is a gap between the bottom edge of the metal electrode (2) and the surface of the solar cell (101).

7. A solar cell metal electrode microstructure according to claim 8, characterized in that: The ARC anti-reflection film (3) and the surface of the solar cell (101) and the surface of the metal electrode (2) are in direct contact and covering relationship.

8. A method for preparing a solar cell metal electrode microstructure, according to the solar cell metal electrode microstructure of claim 7, characterized in that: The details are as follows: Step 1: providing a flip-chip solar cell (101) epitaxial wafer, electroplating copper metal on the cell epitaxial wafer, evaporating a metal electrode, and then bonding a silicon wafer thereon; Step 2: using a mixed solution of ammonia and hydrogen peroxide to etch the substrate to the contact layer (102) in the epitaxial structure, and depositing a silicon oxide mask layer; Step 3: After photoresist is evenly coated on the surface of the silicon wafer, a triangular mask is formed through exposure, development, reflow and other operations; Step 4: Place the sample in ICP and use etching to form a triangular silicon dioxide mask shape. The silicon dioxide mask is triangular and the bottom angle is greater than 45 degrees. Step 5: Transfer the triangular silicon dioxide mask shape to the contact layer (102) by ICP etching, and etch to a depth that reaches the first window layer (104) behind the battery contact layer, and deposit a photoresist mask layer on the contact layer again to form a triangular contact layer (103) morphology; Step 6: Place a metal electrode (2) on the triangular contact layer (103), and then deposit an ARC anti-reflection film (3) on the cell surface to form a complete solar cell chip.

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