Aluminum paste for back electrode of solar cell

A technology for solar cells and back electrodes, applied in the field of aluminum paste, can solve the problems of poor, reduced resistance and uniformity of aluminum paste, affecting the efficiency of solar cells, etc., and achieve the effect of preventing warpage and improving efficiency

Active Publication Date: 2012-07-11
DONGWOO FINE CHEM CO LTD
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Problems solved by technology

However, these additives are problematic because they exist as residues during the aluminum paste calcination process, or form pores, which reduce the resistance and uniformity of the aluminum paste, thereby adversely affecting the efficiency of the solar cell
In addition, the above aluminum paste is problematic because the aluminum powder has a maximum particle size of 10-20 μm, making it difficult for the aluminum paste to evenly contact the textured back surface of the solar cell, and as a result aluminum bumps may be formed due to the holes formed therein. piece

Method used

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  • Aluminum paste for back electrode of solar cell
  • Aluminum paste for back electrode of solar cell

Examples

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Embodiment 1

[0037] Embodiment 1: the preparation of aluminum paste

[0038] 63wt% of D 50 =4~6μm aluminum powder and 7wt% D 50 =2 ~ 4 μm of aluminum powder (4 ~ 6 μm: 2 ~ 4 μm = 9: 1 (weight ratio), aluminum powder total amount = 70wt%), 0.5wt% glass frit with the composition ratio shown in the following Table 1, and 29.5 wt% organic vehicle solution (prepared by dissolving ethyl cellulose in glycol ether) was sequentially mixed with each other to form a mixture, and then the mixture was stirred at 1000 rpm for 3 minutes using a simultaneously rotating and revolving mixer And prepare aluminum paste.

[0039] [Table 1]

[0040] components

Embodiment 2

[0041] Embodiment 2: the preparation of aluminum paste

[0042] Aluminum paste was prepared in the same manner as in Example 1, except adding 42 wt% of D 50 =4~6μm aluminum powder and 28wt% D 50 =2~4 μm aluminum powder (4~6 μm: 2~4 μm=6:4 (weight ratio), aluminum powder total amount=70wt%).

Embodiment 3

[0043] Embodiment 3: the preparation of aluminum paste

[0044] Aluminum paste was prepared in the same manner as in Example 1, except that 66.5 wt% of D was added 50 =4~6μm aluminum powder and 3.5wt% D 50 =2-4 μm aluminum powder (4-6 μm: 2-4 μm=9.5:0.5 (weight ratio), total amount of aluminum powder=70wt%).

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Abstract

Disclosed herein is an aluminum paste for a back electrode of a solar cell, comprising: aluminum powder in which aluminum powder having an average particle size (D50) of 4 ~ 6 [mu]m and aluminum powder having an average particle size (D50) of 2 ~ 4 [mu]m are mixed in a ratio of 6:4 ~ 9.5:0.5 by weight. The aluminum paste is advantageous in that since the contact between aluminum paste and a silicon wafer textured using two or more kinds of aluminum powder having a different average particle size is improved, the warpage of a solar cell can be prevented or the formation of aluminum bubbles or bumps and the occurrence of yellow discoloration can be minimized during a calcination process, the values of short circuit current (Isc) and open circuit voltage (Voc) can be greatly increased, and the efficiency of a solar cell can be remarkably improved

Description

technical field [0001] The invention relates to an aluminum paste used for a back electrode of a solar cell. Background technique [0002] Typically, crystalline silicon solar cells use a P-type silicon substrate with a thickness of 180-220 μm. An N-type impurity layer with a thickness of 0.2 to 0.6 μm is formed on the front surface of the P-type silicon substrate, and SiN for anti-reflection is sequentially formed on the N-type impurity layer x layer and front electrode. In addition, an aluminum electrode was formed on the back surface of the P-type silicon substrate. The forming method of this aluminum electrode is to use screen printing etc. to coat aluminum paste, dry the coated aluminum paste, and then calcinate the dried aluminum paste at low temperature (about 600°C) and high temperature (800-950°C) in two stages. During this calcination process, aluminum diffuses into the P-type silicon substrate to form an Al-Si alloy layer. This Al-Si alloy layer forms a back s...

Claims

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Application Information

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IPC IPC(8): H01B1/22H01B1/04H01L31/042
CPCY02E10/52H01L31/0527H01B1/22H01L31/022425Y02E10/50H01L31/056H01B1/04H01L31/04
Inventor 李昶模李承傭林大成崔亨燮洪胜权
Owner DONGWOO FINE CHEM CO LTD
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