In the initial stage, the silicon material for solar cells is usually discarded in the semiconductor industry. However, with the wide application of crystalline silicon solar cells, the demand for silicon raw materials is increasing, and now the professional production of solar cell grade silicon is mainly used.
The application solution of vacuum pump for production of polysilicon battery ingot is expected to be of great help to manufacturers.
The main equipment used to produce silicon ingot for polycrystalline silicon battery is directional crystallization furnace, and the single crystal furnace is mainly used for monocrystalline silicon solar cell. In the past, the vacuum pumps used in polycrystalline furnace and single crystal furnace were mainly oil pumps, which were solar crystal furnaces. The stable operation of customized models has been praised by the industry, and now all of them are vacuum pumps.
Structure of polycrystalline silicon ingot for solar cell is as follows：
Polycrystalline silicon ingot of solar cell is a kind of columnar crystal, the crystal growth direction is vertical upward, which is realized by directional solidification (also known as controlled solidification and constrained solidification), that is, in the crystallization process, a single direction is formed by controlling the change of temperature field. The heat flux requires that the temperature gradient at the liquid-solid interface be greater than zero, and there is no need for the temperature gradient in the transverse direction to form the columnar crystal with directional growth. However, due to the small plane structure of silicon, the free energy of different crystal faces is different, and the crystal face with the lowest surface free energy grows preferentially. In particular, due to the existence of impurities, the adsorption of impurities on the crystal surface changes the surface free energy, so the growth direction of polysilicon columnar crystal sometimes inclines slightly with fork.
When vacuum pump is used to produce polycrystalline silicon battery ingot, attention should be paid to:
(1) Always pay attention to the oil level.
(2) Open the valve slowly after the pump starts.
(3) Always pay attention to the normal operation of the pump, whether there is special sound, and whether the motor is overloaded.
(4) Pay attention to whether the cooling water is interrupted.
(5) Note that the temperature rise of the pump does not exceed 40 ° C
(6) If the temperature of the rotary vane vacuum pump drops below 5 ° C after stopping, the cold water in the pump must be removed.