Abstract: Three different compression ratios of spiral fins structures are proposed based on traditional spiral fins to significantly enhance the heat transfer of phase-change energy storage devices. Initially, numerical simulations are conducted to investigate the melting process of phase change materials in energy storage tanks with varying compression ratios of spiral fins. Subsequently, the evolution of the temperature field and solid-liquid interface in four energy storage tanks is discussed. The variations of the liquid fraction, average temperature, and average Nusselt number are then analyzed. Following this, the total heat storage capacity, melting time, and average heat storage rate of phase-change materials under different compression ratios are compared. The research results demonstrate that appropriately designing spiral fins with the correct compression ratio effectively promotes the melting of phase change materials in energy storage devices, alleviates the vertical temperature stratification phenomenon, enhances the natural convection of phase change materials, and improves the heat storage performance of phase-change energy storage tanks. It is observed that with an increase in the compression ratio, the heat storage rate initially increases and then decreases while the melting time decreases first and then increases. When the compression ratio is 3, compared to the energy storage tank without compressed spiral fins, the complete melting time of paraffin is shortened by 27.27% and the average heat storage rate is increased by 33.33%. However, with a compression ratio of 7, the average heat storage rate decreases by 25%, and the complete melting time increases by 34.67%.