Research on the performance failure of phase change materials thermal management for lithium battery

Lithium batteries are highly favored in the industry due to their high efficiency performance and long service life, but their thermal safety has always been a major challenge. The application of phase change materials (PCM) can effectively ensure the thermal safety. However, the inability to immediately dissipate heat from the PCM will result in their performance failure. The purpose of this study is to obtain the optimal parameter range considering the critical melting state of PCM through reverse analysis, to overcome the thermal issues during the discharge process of lithium batteries. The experiment and simulation of PCM thermal management are operated by considering input parameters, including liquidus temperature, discharge rate, thermal conductivity, filling thickness, and late heat. An explanation was provided for the entire melting process of PCM. The results showed that the simulation is reliable. The temperature of battery cooled by PCM is 15.4 K lower than that of battery not cooled for a discharge rate of 2C. The PCM with high liquidus temperatures is less likely to result in performance failure for conditions with high discharge rate. The cooling performance increases with the increase of discharge rate under the premise of effective thermal management. There is an optimal value for the filling thickness of PCM in terms of cooling performance and economic benefits. When the latent heat increased from 195 to 275 kJ/ kg, the battery temperature decreased from 311.54 K to 311.02 K and the liquid fraction decreased from 83.16 % to 63.61 % at a discharging rate of 2C. This study provides an important insight for the application and further study of PCM in lithium batteries.