Polysilicon battery velvet color difference solution

In the photovoltaic winter of 2012, we all felt the pain like skin and bone cutting, but the color difference of the components still troubled the photovoltaic people like a python. The following paper analyzed the color difference of polycrystalline batteries in the velvet process and proposed some solutions.

The color of the battery sheet is mainly affected by the velvet, which is a flower piece, a red piece and a part of the yin and yang piece.

The red film is mainly caused by the low amount of texturing corrosion. If the amount of texturing corrosion is less than 3, the damaged layer of the silicon wafer will be removed incompletely, resulting in a red color overall after the PE coating.

The so-called flower piece is caused by excessive corrosion of the texturing. In general, when the amount of texturing corrosion is higher than 4.5, the silicon wafer is equivalent to the polishing treatment, and the cell sheet after the coating is bright, and the grain boundary is also More obvious.

For these two phenomena, the process is adjusted mainly by controlling the amount of corrugated corrosion, so that the ratio of HNO3 and HF tends to be ideal, achieving a better suede effect. The second is to increase the supervision, control the turnover of the shifts and equipment when the equipment is stopped before production. In the production process, technicians and quality inspectors should check the weighing and sueding effect several times to ensure the corrosion amount and suede stability.

For the yin and yang tablets, it can be divided into the following two cases, one is the immersion liquid situation, and the other is the deviation of the corrosion amount between the roads.

The problem of immersion liquid is caused by the horizontal level of the front and rear rollers and the front baffle during the production process. When the silicon wafer enters the velvet tank, there is a time difference between the contact of the liquid and the silicon wafer. In this way, the amount of corrosion in the area where the silicon wafer first contacts the chemical solution is bound to be higher than the area in which the liquid is contacted later. The difference in the amount of corrosion inevitably leads to inconsistent suede effect on the surface of the silicon wafer, and a certain color difference will occur after the PE coating. In order to ensure the effect of immersion, it is necessary to adjust the flanking roller and the baffle.

Specific adjustment method: firstly re-adjust the baffle and roller, level the lower roller, and reduce the roller as much as possible. The baffle is raised, and the height standard is raised by placing the silicon wafer on the front roller of the baffle, and the finger is pressed against the edge of the silicon wafer, and the other side of the silicon wafer is tilted at an angle greater than 15 degrees. You can continue to increase the height of the bezel. From the actual effect, the liquid immersion effect of the silicon wafer can be ensured.

After adjustment, the silicon wafer immersion liquid is uniform, which can ensure the corrosion effect of the silicon wafer is consistent.

There is a deviation in the amount of corrosion between the channels, mainly due to the liquid inlet process. Some old equipment has a liquid inlet pipe, but the inlet of different pipes is a pipe supply, which will cause the least amount of liquid in the inner channel, causing a deviation of the corrosion amount. Some new devices have separate inlet tubes that are porous. Although individuality is guaranteed, there is still a problem with the influent. Therefore, a current limiting device is added to the device to ensure that the amount of liquid is basically the same.

The effect of the immersion liquid is ensured, and the deviation of each lane is also solved, and the yin and yang film caused by the velvet is completely solved.

The page contains the contents of the machine translation.