Optimization of the high-performance multi-crystalline silicon solidification process by insulation partition design using transient global simulations

• The effect of the raise velocities of the partition block during directional solidification of silicon ingots was investigated.
• Global modeling for seed-assisted directional solidification process was performed.
• An improved crystal–melt interface and a low thermal stress can be achieved.
• The results of the simulation were verified in casting experiments.

A transient global model was established to investigate the effect of the raise velocities of the partition block on the crystal growth rate, the crystal–melt (C–M) interface and the thermal stress distribution during the solidification process. The simulation results showed that among the different raise velocities of the partition block, initially slowly raising and then rapidly raising the partition block was the most favorable for the solidification process. A slightly convex C–M interface and low thermal stress distribution were obtained, and a fast crystal growth rate was also achieved. Thus, this design was implemented in casting experiments, and the experimental results indicated that this design was beneficial for optimizing the C–M interface in the solidification process. The average conversion efficiencies of high-performance multi-crystalline silicon solar cells was about 0.13% higher with this design (18.18%) than with a fixed partition block design (18.05%).