Method for preparing point contact electrode at back of solar cell by utilizing laser induced thermit reaction

A backside point contact and thermite reaction technology, applied in the field of solar energy, can solve the problems of reducing battery short-circuit current, failure to form ohmic contact, material damage, etc., to increase short-circuit current and open-circuit voltage, reduce carrier recombination rate, reduce The effect of small damage

CN101546790AInactive Publication Date: 2009-09-30SUN YAT SEN UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2009-09-30
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for preparing a point contact electrode at the back of a solar cell by utilizing laser induced thermit reaction, which comprises the following steps in sequence: plating a passivation media layer on the back of a silicon substrate; steam-plating an aluminum layer on the passivation media layer; printing or coating thermite on the aluminum layer; and igniting the thermite by the radiation of laser to result in the thermit reaction for generating high temperature so that the aluminum layer and the silicon substrate are molten and then are crystallized and form better ohmic contact and aluminum back surface field. The invention adopts laser to indirectly sinter an electrode, i.e. the laser is used to induce spontaneous reaction of the thermite, high temperature generated by the reaction make aluminum and the silicon from better ohm contact, therefore, the prepared solar cell has smaller series resistance; meanwhile, the aluminum and the silico forms the aluminum back surface field, and the prepared solar cell has bigger short circuit current. By adopting the method of the invention, the laser does not directly radiate a metallic film, which reduces the damage to the silicon to be lowest and further improves the short circuit current of the solar cell.
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Description

technical field

[0001] The invention belongs to the technical field of solar energy, and in particular relates to a method for preparing solar cell electrodes. Background technique

[0002] Exploring new processes for solar cells to reduce costs while improving conversion efficiency is the only way to industrialize solar energy. The recombination on the back surface of the silicon wafer has a great influence on the efficiency of solar cells. The existing electrode sintering process forms a metal-semiconductor interface on the entire back of the solar cell, which has a high minority carrier recombination speed, resulting in low short-circuit current of the solar cell. Therefore, the back electrode of the point contact method has attracted more and more attention. It can reduce the area of ​​the metal-semiconductor contact area, thereby effectively reducing the surface recombination rate of the solar cell, and has a great effect on improving the performance of the solar cell,...

Examples

Embodiment Construction

[0018] The method for preparing a point-contact electrode on the back of a solar cell by using laser-induced thermite reaction provided by the present invention comprises the following steps:

[0019] (1) The front surface of the silicon substrate 1 is cleaned and textured, diffused to obtain the front surface emission junction region 9, and the front surface anti-reflection film 10 (such as SiNx: H or SiO 2 etc.), prepare the front silver grid line electrode 11, such as figure 1 shown;

[0020] (2) Coating a layer of passivation dielectric layer (2) (such as SiNx: H or SiO on the back side of silicon substrate 1 2 etc.), such as figure 2 shown;

[0021] (3) A layer of aluminum layer 3 is vapor-deposited on the passivation medium layer 2, the thickness of the aluminum layer 3 is 0.1-10um, such as image 3 shown;

[0022] (4) Printing or coating dot-shaped thermite 4 arranged in a certain array on the aluminum layer 3, such as Figure 4 shown;

[0023] (5) Ignite therm...