Experimental and modeling investigation on thermal risk evaluation of tabs for pouch-type lithium-ion battery and the relevant heat rejection strategies

Abstract

Thermal safety is one of the primary requirements for electric vehicles (EVs). Overheating by an external or internal heat source will induce the onset of thermal runaway. An overheating risk caused by tabs of pouch-type lithium-ion batteries was reported and the relevant heat rejection strategies were investigated in this paper. The positive tab showed a much higher temperature rise than that in the body and the negative tab of pouch-type lithium-ion batteries. The temperature reached 70.4 °C in the beginning 100 s with a charge rate of 2 C-rate, showing a fast temperature response. Besides, the largest temperature difference between the charge and discharge process was about 20.2 °C (2 C-rate), which indicates that the positive tab in the charging process is more dangerous than that in discharging process. Moreover, an electro-thermal model was applied to investigate the potential risk of tabs in the pouch-type lithium-ion battery. An extreme temperature rise (∼ 350 °C) in the positive tab showed a potential thermal risk in a high charging rate (6C). And the temperature at the tab can only be controlled under a relatively high heat transfer coefficient (higher than 100 W·m−2·K−1). This work is meaningful for the development of a thermal management strategy in a battery pack with fast charging technologies.