A Test Approach for Evaluating the Safety Considering Thermal Runaway Propagation within the Battery Pack

Accidents with thermal runaway (TR) of lithium ion batteries occurred sporadically. In order to diminish the TR hazard from abuse conditions, battery must pass specific test standards. However, the TR triggering at single cells cannot be totally eliminated although passing the test standards. The total energy of the battery pack during TR propagation can be huge and catastrophic. Therefore the prevention of the TR propagation must be considered in safety design of the REESS. A standardized test approach to evaluate the hazard potential of TR propagation in the battery pack is proposed in this paper. The judgement of TR is determined by three proposed criteria. Experiments are conducted to validate the proposed approach to evaluate safety of the battery pack under TR propagation. A lumped parameter model with 18 series cells is proposed to simulate the heating triggered TR propagation experiments. From the simulation results, it is indicated that heating power has significant effect on TR propagation. Large heat power is recommended in the test approach to induce the effect on TR propagation characteristics.