Title: Influence of capacity and energy density of lithium-ion battery on thermal reaction during high rate charging

Authors: Xiaogang Wu; Haoqi Guo; Jiuyu Du

Addresses: College of Electrical and Electronics Engineering, Harbin University of Science and Technology, Harbin, 150080, China ' College of Electrical and Electronics Engineering, Harbin University of Science and Technology, Harbin, 150080, China ' State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing, 100084, China

Abstract: NCM ternary lithium-ion batteries have been widely used in electric vehicles. However, the negative impacts of increased energy density cannot be ignored, particularly the heat generation from batteries during high-rate charging. Further analysis is required on the heat generation problem in high energy density NCM batteries for safety. In this study, the thermophysical parameters of batteries with different energy densities are tested, then a heat generation model during charging is constructed based on Bernardi equation. Furthermore, two NCM batteries with different energy densities are selected to analyse the heat generation when the charging rate varied from 1 C to 4 C. The results show that under the same charging rate, heat generation in a higher energy density NCM battery is more evident, and the average heat generation rate can reach 2.36 times that of a lower one. In addition, factors that cause the increased heat generation in NCM batteries are quantified.

Keywords: high energy density; lithium-ion battery; thermos-physical parameters; capacity and size; high rate charging; temperature rising; heat generation rate.

DOI: 10.1504/IJVD.2020.114778

International Journal of Vehicle Design, 2020 Vol.83 No.1, pp.1 - 22

Received: 18 Nov 2019
Accepted: 03 May 2020
Published online: 06 May 2021 *

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