Lifetime Prediction and Maintenance Assessment of Lithium-ion Batteries Based on Combined Information of Discharge Voltage Curves and Capacity Fade

Current two-stage Lithium-ion battery degradation models commonly treat the change point (CP) in two ways. First, it is a random variable, which increases model complexity and the computational cost for predicting the remaining useful life (RUL). Second, it is a deterministic value, which will simplify the degradation models. The value of CP needs to be well identified for an accurate description of the degradation process. However, the capacity data is generally non-monotonic due to energy regeneration, which makes it hard to use in determining the CP. In addition, our laboratory data on the discharge voltage profile shows a potential for CP detection. Thus, we developed a hybrid method that combines dynamic time warping and nonnegative matrix factorization to detect the CPs of battery cells by using voltage discharge profiles. Then, we proposed a two-stage Wiener process incorporating CP detection method to describe the battery capacity degradation pattern. The proposed model is applied to our lab data and NASA data to predict RUL. Finally, maintenance strategies are analyzed to enhance the management of Lithium-ion batteries by minimizing the long-term cost rate under different replacement policies.