Thermal management investigation for lithium-ion battery module with different phase change materials

Lithium-ion batteries, with their advantages of high energy and power density, have attracted much attention for application in electric vehicles and hybrid electric vehicles. However, there have been increasing reports of lithium-ion batteries catching fire and exploding in recent years, so there is a need for a battery thermal management (BTM) system to ensure battery safety performance. In this study, a novel shaped stabilized structure (paraffin/expanded graphite/epoxy) of composited materials was investigated for the 18 650 batteries module. The selected batteries were evaluated at different conditions to ensure the consistency of batteries initially. Then, different kinds of PCM were applied in the batteries module for thermal management, such as PCM 1 (pure paraffin), PCM 2 (EG 20%, paraffin 80%) and PCM 3 (EG 3%, epoxy 47%, paraffin 50%). The maximum temperatures of the battery modules with PCM 2 decreased more than 10%, 12% and 20% at 1C, 3C and 5C discharge rates, respectively, while paraffin mixed with expanded graphite. Furthermore, PCM can be modified by epoxy: the temperature of the module with PCM 3 was 59.79 °C while that of the module with PCM 2 was 64.79 °C after 30 charge–discharge cycles, revealing that epoxy as a plasticizer can cure the melting paraffin, preventing PCM leakage as the cycle number of the battery increases. The composite materials provide a promising solution to control temperature and decrease temperature difference in batteries modules.