The Comparison of Thermal Stability and Safety between Fresh and Aging Large Capacity Lithium Ion Battery with Silicon Carbon Anode

Due to the high energy density, lithium ion battery (LIB) plays an important role in electric vehicle (EV). However, the requirement to the energy density keeps increasing. More and more materials are selected to improve the energy density to provide more distance for EV. Silicon, as a famous anode material, provides much higher specific capacity (3579-4200 mAh/g) than graphite (372 mAh/g) does. This research focused on thermal stability and safety of a 30Ah battery with silicon carbon anode. Aging battery would also be compared with the fresh battery after several cycles to different state of health (SOH). The batteries would be analyzed by accelerating rate colorimeter (ARC) to determine the safety. The differential scanning colorimeter (DSC) evaluated the thermal stability of the batteries. The thermal stability of ARC is decided by T1, T2 and T3 which are the self-heating temperature, thermal runaway triggered temperature and the highest temperature, respectively. The scanning electron microscope (SEM) could observe the surface differences with different SOH and various silicon proportion. The research revealed an overall safety assessment of the lithium ion battery with different content of silicon anode under different SOH. Keywords: Lithium ion battery, silicon carbon, thermal runaway, thermal stability Figure 1