Automatic liquid-replenishing device for diffusion furnace in solar battery production

Abstract

The invention belongs to the field of solar photovoltaic power generation, in particular to an automatic phosphorus oxychloride liquid-replenishing device for a diffusion furnace in solar battery production, which comprises a phosphorus oxychloride storage tank and a source bottle, wherein the phosphorus oxychloride storage tank and the source bottle are communicated through a pipeline with a cut-off valve, the lower end of the pipeline stretches into the source bottle, and the distance from an outlet hole at the bottom end of the pipeline to the bottom of the source bottle basically equals to the liquid level height set in the source bottle. Through the automatic liquid-replenishing device, the trouble of taking the source bottle out of a thermostatic bath to observe the liquid level every time is avoided, the operation is convenient, the temperature of the source bottle can not fluctuate, and automatic continuous liquid replenishment without energy driving is realized; the accuracy of liquid level control is high, the quality of the product and the stability of the process are improved, the production efficiency is increased, and the production cost is reduced.

Description

technical field [0001] The invention relates to solar cell production technology, in particular to an automatic liquid replenishment device for phosphorus oxychloride in solar cell production. Background technique [0002] When making the PN junction of solar cells, protective gas (nitrogen) is usually used to bubble or blow over the surface of the constant temperature phosphorus oxychloride liquid source bottle, and the impurity source steam is brought into the high-temperature diffusion furnace, which is heated with the silicon wafer at high temperature. The surface reacts to generate phosphorus atoms, and diffuses doping into the silicon wafer to form a PN junction. Phosphorus oxychloride (PoCl3) is a liquid phosphorus source, which has a high saturated vapor pressure at room temperature, so the liquid level of phosphorus oxychloride in the source bottle will continue to drop. When the liquid level drops to a lower position, there will be a big difference in the uniformi...

AI Technical Summary

Problems solved by technology

The liquid replenishment method in the prior art, one is to regularly take out the source bottle from the constant temperature tank to observe the liquid level, and determine whether to replenish the liquid, which is troublesome and will also affect the ambient temperature and production efficiency of the source bottle; Surface sensor, through the controller to control the opening and closing of the solenoid valve to realize automatic liquid replenishment, but the complexity of the device is affected by the reliability probability of electronic components, which directly affects the accuracy of the liquid level, resulting in a decline in the yield rate and increased investment costs

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