Title: State estimation method for power lithium-ion battery based on dynamic equilibrium voltage

Authors: Qiuting Wang; Wei Qi

Addresses: Department of Electric and Information Engineering, Zhejiang University City College, 51 Huzhou Road, Hangzhou, 310015, China ' Department of Electric and Information Engineering, Zhejiang University City College, 51 Huzhou Road, Hangzhou, 310015, China

Abstract: The state parameters of power lithium-ion battery include the state of charge (SOC), the state of health (SOH) and the state of power (SOP). These three parameters are used to indicate the current remaining mileage, the maximum endurance mileage and the acceleration performance, respectively. The dynamic equilibrium voltage (DEV) based on battery electric characteristics is studied in this paper. The online state estimation problem of a battery cell under dynamic working conditions is discussed in depth. We chose the DEV value as the characteristic parameter to estimate the SOC and SOH value online. The main focus of our researches is the mathematical model of power lithium-ion battery is established based on the internal dynamic behaviour. Secondly, the state space equations are derived to describe the model parameters and the working performance. Thirdly, the SOC and SOH values are estimated accurately using only the DEV curve results under the battery's all-new state. Finally, our experiments were processed under different temperatures and different ageing degrees to investigate the new model and to validate our new estimation method.

Keywords: lithium-ion battery; dynamic equilibrium voltage; SOC; state of charge; SOH; state of health; SOP; state of power; online estimation.

DOI: 10.1504/IJEHV.2018.095712

International Journal of Electric and Hybrid Vehicles, 2018 Vol.10 No.2, pp.95 - 112

Received: 29 Jul 2017
Accepted: 11 Aug 2017
Published online: 18 Oct 2018 *

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