Title: Study on influence of sorting parameters to lithium-ion battery pack life-cycles based on cell consistency

Authors: Qiuting Wang; Wei Qi

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

Abstract: The lithium-ion batteries have been applied as the most extensive and stable power sources in electric vehicles (EVs). The variation of cell parameters is a critical factor to the safety, energy density, life and stability of battery pack. The main efforts of our studies are, firstly the current distribution of two parallel cells is obtained based on the equivalent circuit method (ECM) in actual operation condition. The distribution model was verified and can be used in serial, parallel and mixed constructions. Secondly, the self-discharge rate is certificated as an important parameter to affect cell-consistency in ageing process. The rate value was deduced based on the solid electrolyte interface (SEI) membrane growth model. Thirdly, a reliable theoretical basis for optimising the cell sorting method is provided. Lastly, the ageing tests using 18 cells in parallel construction were conducted. The experimental results indicate that our new sorting method and sorting parameters can improve the cell consistency performance in ageing process.

Keywords: lithium-ion battery; sorting parameters; current distribution; cell consistency; equivalent circuit method; solid electrolyte interface.

DOI: 10.1504/IJEHV.2018.097376

International Journal of Electric and Hybrid Vehicles, 2018 Vol.10 No.3, pp.223 - 235

Received: 09 Feb 2018
Accepted: 06 Aug 2018

Published online: 15 Jan 2019 *

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