Functional water droplets-SiC particles network structure formed in paraffin to achieve lithium-ion battery thermal management for both hot and cold conditions

The composite phase change materials (CPCMs) are always created by integrating high thermal conductivity additives with paraffin, facilitating heat dissipation during the battery discharging process. However, under cold conditions, the battery needs to utilize the paraffin intrinsic low thermal conductivity to reduce heat loss. Thus, creating a CPCM that rapidly dissipates heat at high temperatures and retains heat at low temperatures is a new challenge. This research develops a novel CPCM with the water droplets-SiC particles network inside the paraffin matrix. 5 wt% SiC particles and 15/25/35 wt% water enhance the thermal conductivity from 0.24 Wm −1 K −1 to 1.29/1.45/1.68 Wm −1 K −1 , respectively. The network acts as a thermally conductive pathway, leading to an average decrease of 3.7 °C or 4.4 °C in the final battery temperature at 2C or 3C discharge rate. Water crystallizes and releases heat, thereby this process maintains the temperature of battery at 0 °C for an extended period exceeding 16 min. Moreover, network stability is related with water content. After 15 heating or cooling cycle tests, droplet coalescence or deformation is less prone to occur when CPCMs with a water content of 15/25 wt% than that with 35 wt%, preventing the network structural breakage.