Estimation of Real-Time Peak Power Capability of a Traction Battery Pack Used in an HEV

Battery peak power capability estimation has an important theoretical significance and utility value for proper use of a battery and to help extend its lifetime. It is an important part of a battery management system. The paper presents an algorithm for estimating the dynamic peak power capability of a battery pack. The algorithm is based on a dynamic battery model taking into consideration constraints of rated, current, voltage and state of charge. The suitability of alternative equivalent circuit models for lithium-ion batteries was also analyzed. It is shown that using Thevenin´s model, the estimation algorithm could compute the dynamic battery peak power in real-time and could provide real-time estimates of the charged and discharged power in an electric vehicle so that the battery may be used within its safe operating limits.