Preparation method for high open-circuit voltage polycrystalline solar cells

The invention relates to a preparation method for high open-circuit voltage polycrystalline solar cells. A temperature-variable deposition high-temperature knot pushing technology is adopted in the diffusion process, and the dense grid design of 90 fine grids is adopted by positive pole printing patterns during the positive-pole printing process. The temperature-variable deposition is the process of increasing the temperature to 860 DEG C, temperature-variable deposition for 10 min is conducted on a silicon wafer during the temperature-increasing process, the mixture gas of large N2, O2 and small N2 is led in, and the proportion, by volume, of the small N2 is 7%; the high-temperature knotting pushing process is that the temperature is kept at 860 DEG C stably, the small N2 is stopped being led in, the large N2 and the O2 are led in for impurity re-distribution, the time is controlled to be within 17 min, and the proportion, by volume, of the O2 is 15%. The preparation method enables the square resistance of the silicon wafer to be from 90omega/sq to 95omega/sq, and compared with one-time constant-temperature deposition diffusion, the polycrystalline solar cells produced under the situation that the cost is not increased can obtain the higher open-circuit voltage.