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%). (C) 2015 Published by Elsevier B.V.