Experimental investigation of the effect of phase change materials on the behavior of battery at high-rate discharge in electric tools

Abstract

Phase change materials (PCMs) are currently popular in battery thermal management for electric tools discharged at high-rate due to their small size and ecologically harmless. However, there is currently a little discussion on batteries with high discharge rates (≥10C) under PCMs thermal management. An experimental study was performed in this work to investigate the effects of the thickness of PCMs (0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm), depth of discharge (DOD) levels (70% and 80%), and ambient temperature (25 °C and 40 °C) on the behavior of the battery at high-rate discharge. The results indicate that wrapping 2 mm PCMs can reduce the surface temperature of the battery and increase the discharge time by 64 s at 15C discharge. In addition, the aging of battery wrapped with PCMs is classified into three stages under the DOD limitation, which has a strong correlation with temperature. Furthermore, using PCMs under appropriate operating conditions can effectively prevent the battery temperature from overheating and improve the discharge capacity. At 25 °C and 10C discharge rate, the cycle life and total capacity are improved by 14% and 24%, respectively.