The experiment and modeling for sealing strength degradation evaluation of lithium-ion pouch cell

The pouch cell is becoming a mainstream among a variety of power batteries, because of its higher energy density and lower weight. Due to the probability of gas production in a pouch cell, the increasing internal gas pressure will cause strength degradation of the sealing area. This process significantly decides the safety and remaining useful life (USL) of a pouch cell. This paper evaluates the strength degradation of sealing adhesive area through accelerated degradation test (ADT) and cohesive zone model (CZM), and provides a method to predicting the sealing life. In the experiments, the load-displacement relation was obtained. The modified exponential CZM was used to describe the mathematical relation and the sealing strength degradation is evaluated by the loss of fracture energy. This modified model is validated well by the testing data. Evaluation of the sealing life can be predicted with the condition of internal gas pressure.