Internal Short Circuit Trigger Method for Lithium-Ion Battery Based on Shape Memory Alloy

Internal short circuit (ISCr) is one of the major safety issues of lithium batteries and would lead to thermal runaway of batteries. Repeating ISCr in laboratory requires to create small-scale short circuit inside integrated batteries, which is very hard for existed safety test methods. In this paper, a novel ISCr trigger method based on shape memory effect of shape memory alloy (SMA) is proposed, which is easy to be implanted into batteries while has minor influences on batteries normal performance. The proposed SMA ISCr trigger method is employed to conduct ISCr experiments, including the severest type of ISCr, the Aluminum-Anode ISCr, and the most common type of ISCr, the Cathode-Anode ISCr. The experiments results show that the Aluminum-Anode ISCr leads to explosion while the Cathode-Anode ISCr only leads to mild self-discharging. Compared with the nail penetration test, the proposed SMA ISCr trigger method in the Aluminum-Anode ISCr experiment has 1) better consistency, given that all of the 4 tested batteries have their maximum temperature in the range of 383∼393°C; 2) better reliability in evaluating battery safety properties, given that all of the 4 tested batteries have the repeatable explosion behavior. The relative ease of inserting this controllable SMA ISCr and the repeatability of the produced data can lead to better modeling and detection techniques of battery internal shorts such as plating and dendrite formation.