Aluminum powder for double-sided PERC crystalline silicon solar cell and aluminum paste prepared from aluminum powder

Abstract

The invention discloses aluminum powder for a double-sided PERC crystalline silicon solar cell, belongs to the field of materials, and the aluminum powder for the double-sided PERC crystalline siliconsolar cell has the oxygen content of 0.3-0.7%, the maximum particle size of 0.1-30 microns and the apparent density is 0.55-0.9 g / cm < 3 >. When the aluminum powder for the double-sided PERC crystalline silicon solar cell is used for the crystalline silicon solar cell, the consequences of slurry leakage, pollution and the like caused by damage to a printing screen can be avoided. Under the condition of high-temperature fast burning, aluminum powder particles are rapidly close to each other, barriers among the particles are eliminated, so that low aluminum paste line resistance and low batteryseries resistance are brought, and the photoelectric conversion efficiency of the battery is improved. The invention further provides aluminum paste prepared from the aluminum powder for the double-sided PERC crystalline silicon solar cell.

Description

technical field [0001] The invention belongs to the field of materials, and in particular relates to an aluminum powder used for PERC crystalline silicon solar cells and an aluminum paste prepared therefrom. Background technique [0002] The back point contact structure crystalline silicon solar cell is also called local aluminum back field or rear passivation, referred to as LBSF or PERC (passivation emitter rear contact) cell, which is a high-efficiency cell that is convenient for industrialization. Compared with conventional batteries, the back of this type of structural battery is coated with a passivation film. The passivation film is perforated or grooved by laser and other means, and the aluminum paste is printed on the passivation film. The back electric field is drawn out by point or line contact. This battery structure not only maintains the back field effect, but also reduces the contact area between the metal and semiconductor on the back, and the recombination r...

AI Technical Summary

Problems solved by technology

[0004] However, the activity of aluminum powder has a great influence on the series resistance of the electrical performance parameters of PERC crystalline silicon solar cells. Aluminum powder will melt at 660°C. Due to the barrier of oxygen between aluminum powder particles with low activity and high oxygen content, its sintering compactness Relatively low; at the same time, the existing low-activity aluminum powder has high oxygen content and high resistance, resulting in large line resistance and series resistance, which is not conducive to the conversion of light energy into electrical energy by the battery

In addition, the existing technology does not specify the maximum particle size of aluminum powder. At present, the screen size commonly used for printing aluminum paste on PERC crystalline silicon solar cells is 400-18 (mesh number 400, wire diameter 18), and the mesh size is converted to 45.5 *45.5μm, the particle size that can pass through is generally half of the mesh size, and the fineness of aluminum paste products is usually specified at 22.5μm, with a maximum particle size D 100 Although the aluminum powder particles are very small, if they are printed for a long time, they will add up and scratch the printing screen continuously, and finally puncture the printing screen, causing slurry leakage and polluting the cells, which will cause the parallel resistance to decrease, and then leading to a decrease in the conversion efficiency of the cell

The existing technology does not specify the bulk density of aluminum powder, so the fluidity of aluminum powder is not limited, and it is difficult to ensure sufficient dispersion of aluminum powder when making aluminum paste