Annealing treatment process for PERC battery

Abstract

The invention discloses an annealing treatment process for a PERC battery. The annealing treatment process comprises the following steps of preparing an aluminium oxide thin film on the back surface of a silicon wafer, and performing annealing treatment on the silicon wafer. By performing the annealing treatment on the aluminium oxide thin film in the PERC battery, the interface recombination is lowered, the minority carrier lifetime of the silicon wafer is prolonged, and the adverse effect on the passivation effect of the aluminium oxide thin film in the existing PERC battery preparation process is overcome; and meanwhile, the annealed silicon wafer is prepared into the PERC battery, and the average value of the photoelectric conversion efficiency reaches 21.0%; and compared with the conventional preparation process (without annealing treatment), the photoelectric conversion efficiency is improved by 0.2%, and relatively good electrical performance is achieved.

Description

technical field [0001] The invention belongs to the field of solar cell manufacturing, and in particular relates to an annealing process for PERC cells. Background technique [0002] PERC cell is a new type of high-efficiency solar cell, and a layer of aluminum oxide film is prepared on the back. In the PERC cell, the field effect of aluminum oxide is used to passivate the surface of the silicon wafer, which can improve the minority carrier lifetime of the silicon wafer. [0003] In the existing PERC battery preparation process, the high-temperature sintering process is usually used to activate the field effect of aluminum oxide. There are two defects in this process: (1) The time is too short, and the time above 500 ° C is only 20-30 seconds. However, the high temperature time is too short to effectively activate the field effect of Al2O3, that is, the sintering time is too short, the negative charge density in Al2O3 is too low, and the strength of the field effect is not ...

AI Technical Summary

Problems solved by technology

[0003] In the existing PERC battery preparation process, the high-temperature sintering process is usually used to activate the field effect of aluminum oxide. There are two defects in this process: (1) The time is too short, and the time above 500 ° C is only 20-30 seconds. However, the high temperature time is too short to effectively activate the field effect of Al2O3, that is, the sintering time is too short, the negative charge density in Al2O3 is too low, and the strength of the field effect is not enough to ensure the full play of Al2O3 film. Effective passivation effect

(2) The peak temperature is too high, and the peak temperature reaches 800°C. If the peak temperature is too high, it will easily lead to inversion, that is, if the peak temperature is too high, it will cause too much positive charge in silicon, and the positive charge itself will become the recombination of electrons. center, resulting in a decrease in the life expectancy of the minority

In addition, due to the need to take into account the sintering effect of aluminum paste and front silver, there is little room for adjustment of the temperature curve during the sintering process

It can be seen that the passivation effect of the aluminum oxide film cannot be brought into full play in the existing preparation process.

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