Energy Procedia, vol. 142, pp. 3578–3583, August 2020, DOI: 10.1016/j.egypro.2017.12.248

Energy State of Health Estimation for Battery Packs Based on the Degradation and Inconsistency


Weiping Diao1,2,3, Jiuchun Jiang1,2, Caiping Zhang1,2, Hui Liang1,2 and Michael G. Pecht3
1 National Active Distribution Network Technology Research Center (NANTEC), Beijing Jiaotong University, Beijing 100044, China
2 Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing Jiaotong University, Beijing 100044, China
3 CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, USA

Abstract:

To identify the end-of-life batteries, the capacity and internal resistance are mostly used to evaluate the state of health (SOH) for battery cells and packs. However, these two methods may lead to a different conclusion concerning the SOH of the batteries due to the independence between the capacity and internal resistance. In this paper, the energy SOH for a battery pack is proposed and defined as the ratio of the current maximum available energy (MAE) to the rated total energy. Incorporating both the degradation and inconsistency of the capacity and internal resistance, the energy SOH is more appropriate and accurate to reflect the actual state of battery pack compared to the capacity and power SOH. The superiority of this method is shown through the data analysis and comparison of different methods.

This article is available online here.

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