Abstract: The state of power of lithium-ion battery directly determines the acceleration performance and the braking energy recovery rate of electric vehicles. The state of power cannot be measured directly, so the accurate prediction of which is crucial and difficult. This is due to the complex electrochemical characteristics inside the battery, especially the operation of the battery is a coupled process of electro-thermal characteristics. Excessive charging and discharging power can cause overheating of batteries, which may lead to accelerated degradation of battery life and even cause safety accidents. Therefore, battery temperature is introduced as one of the most important constraints of peak power. Peak power prediction is realized by combining the constraints of battery temperature, voltage and SOC. Firstly, The electro-thermal battery model is established to accurately describe the electrical and thermal dynamic characteristics of the battery. Then the state of power can be predicted with multi-constraints of terminal voltage, state of charge and temperature of battery. Finally, an improved parameter identification method of battery thermal model is proposed. The performance of battery model and power prediction mothed are demonstrated by experiments under different temperatures and dynamic characterization schedules. The experimental results show that the proposed method can effectively predict the power of battery charging and discharging and improve the safety of battery system.

Key words: electric vehicle, lithium-ion battery, state of power, electro-thermal model, multi-parameter constraints