Battery Management System (BMS) mainly focused on the estimation of State-of-Charge (SOC) previously. However, the single SOC could not reflect the true state of battery. Life prediction and performance state estimation becomes an increasingly important issue in each battery life stage. A practical and accurate battery life model is their basis. Much research work has been done in recent years to improve the accuracy and application range of battery life model. This paper introduces commonly used battery life modeling methods and summarized the characteristics of each model and their common applications, and the emphasis for future study is proposed as well.