Method for opening passivation layer on back surface of solar cell

A technology of backside passivation and solar cells, which is applied in the direction of circuits, electrical components, sustainable manufacturing/processing, etc., can solve the problems of low stencil life, accelerated stencil replacement speed, and uneven opening width, so as to reduce production costs , Improve the use value and the effect of good industrial prospects

Inactive Publication Date: 2012-05-02
TIANWEI NEW ENERGY HLDG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has always been limited by the line width of screen printing, and can only produce openings above 80 μm. However, researchers have improved screen printing so that openings of 40 μm can also be obtained by using corrosive paste openings.
However, in this technology, the price of commonly used corrosive pastes, such as ammonium fluoride, is relatively high, and when printing corrosive pastes, the life of the stencil is relatively low, which will speed up the replacement of the stencil and increase unnecessary Necessary production cost; at the same time, the graphic edge of the opening of the screen printing corrosive paste is not neat, resulting in uneven opening width, and it is difficult to accurately design the opening width

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1 The method of opening the passivation layer on the back of the solar cell

[0020] On the back of the solar cell with a silicon nitride passivation layer, use paraffin to form a mask at the part where the subsequent metal and silicon contact. The method of forming the mask is inkjet printing; then clean the passivation layer with hydrofluoric acid, and The passivation layer at the opening is completely removed, and excess hydrofluoric acid is discarded; finally, the paraffin mask is cleaned with a mixed solution of NaOH and deionized water (DI), and the mass percentage of NaOH is 0.5%.

[0021] It is found through experiments that when the mass percentage of NaOH or KOH in the mixed solution is lower than 0.5%, the paraffin wax cleaning is not thorough, and when it is higher than 7%, it will affect the surface of the silicon wafer. Therefore, the mass percentage of NaOH is preferably 0.5%-7%.

[0022] In this method, an inkjet printing paraffin mask can be...

Embodiment 2

[0023] Embodiment 2 The method of opening the passivation layer on the back of the solar cell

[0024] On the back side of the solar cell with a silicon dioxide passivation layer, use paraffin to form a mask at the part where the subsequent metal and silicon contact. The method of forming the mask is an inkjet printing method; then clean the passivation layer with hydrofluoric acid and wait The passivation layer at the opening is completely removed, and excess hydrofluoric acid is discarded; finally, the paraffin mask is cleaned with a mixed solution of NaOH and DI, and the mass percentage of NaOH is 10%.

Embodiment 3

[0025] Embodiment 3 The method of opening the passivation layer on the back of the solar cell

[0026] On the back of the solar cell with a silicon nitride passivation layer, use paraffin to form a mask at the part where the subsequent metal and silicon contact. The method of forming the mask is inkjet printing; then clean the passivation layer with hydrofluoric acid, and The passivation layer at the opening was completely removed, and excess hydrofluoric acid was discarded; finally, the paraffin mask was cleaned with a mixed solution of NaOH and DI, and the mass percentage of NaOH was 7%.

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PUM

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Abstract

The invention discloses a method for opening a passivation layer on the back surface of a solar cell. In the method, the opening operation is performed by adopting the conventional equipment; the width of the opening obtained by using the method is equal to the width of the opening obtained by using an improved corrosive slurry opening technology, namely a better opening width can be obtained without changing the equipment, so that the utilization value of the old equipment is increased; meanwhile, by adopting the opening technology, the price of the used acidic liquid and the price of the later-stage cleaning solution are low; screen printing is not required, so damages to the equipment is avoided; therefore, the production cost is reduced; and the method has a good industrial prospect.

Description

technical field [0001] The invention relates to a method for opening a passivation layer on the back of a solar cell. Background technique [0002] For the solar cell, for the front electrode, considering the influence of shading, the electrode is a finger-shaped Ag electrode, and the Ag electrode is divided into a main grid and a fine grid. The position corresponding to the main gate line on the back of the silicon wafer is the back electrode, and the remaining part is screen-printed with aluminum paste. The aluminum forms a silicon-aluminum eutectic during high-temperature sintering, resulting in a PP+ high-low junction, preventing minority carriers from migrating to the back, reducing the Recombination rate of the back surface. Although the recombination rate of the back surface has decreased to a certain extent, the surface in contact with aluminum and silicon is still a typical high recombination area, and the recombination rate is above 500cm / s. In addition, due to t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/18
CPCY02P70/50
Inventor 路忠林李丽陈先知赵丽燕许佳平盛雯婷张凤鸣
Owner TIANWEI NEW ENERGY HLDG
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