Abstract: Thermal runaway and larger volume expansion caused by temperature rise are the main reasons for explosions and cycle performance degradation during the charge and discharge of lithium-ion batteries (LIBs). Meanwhile excessive charging time directly results in lower charging efficiency. In order to improve the charging efficiency and as-sess the temperature and stress distributions of LIBs, a thermo-mechanical coupling model of a cylindrical LIB with thermal radiation effect is developed during fast charging in this work. Then taking 18650 lithium-ion battery as the research object, the charging efficiency, temperature and stress distributions are compared between fast charge and galvanostatic operation. Finally, the influences of initial temperature, convective heat transfer and ther-mal radiation on the temperature, radial and hoop stresses of the battery during the charge are simulated, respectively. Numerical results show that the fast charge reduces the charge time within the service range of the temperature and stress, and the charge efficiency in-creases by 20.8%. The temperature of LIBs during the charge will be effectively reduced by reducing the initial temperature, or increasing the convective heat transfer coefficient, or improving the thermal radiation coefficient.

Key words: fast charge, thermo-mechanical coupling, thermal radiation, lithium-ion battery