Premium
Investigation on Cell Performance and Inconsistency Evolution of Series and Parallel Lithium‐Ion Battery Modules
Author(s) -
Wang Xueyuan,
Fang Qiaohua,
Dai Haifeng,
Chen Qijun,
Wei Xuezhe
Publication year - 2021
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202100072
Subject(s) - battery (electricity) , equalization (audio) , series and parallel circuits , convergence (economics) , computer science , power (physics) , series (stratigraphy) , voltage , process (computing) , internal resistance , divergence (linguistics) , consistency (knowledge bases) , lithium (medication) , lithium ion battery , reliability engineering , parallel computing , electrical engineering , algorithm , engineering , physics , artificial intelligence , biology , philosophy , endocrinology , economic growth , linguistics , operating system , paleontology , quantum mechanics , economics , decoding methods
Lithium‐ion battery cells are usually connected in series or parallel to form modules to meet power and energy requirements for specific applications. Inconsistency of the cells’ performance, i.e., capacity and internal resistance, is initially formed during production. Then the inconsistency evolves in the lifespan. Herein, the performance and inconsistency evolution of the series and parallel modules for the design and management guide are investigated. A quantitative analysis of the performance and inconsistency is made. The performance and inconsistency evolution are investigated experimentally. Based on it, the trend judgment of the inconsistency evolution is derived. It is found that the cell performance in series modules is self‐divergent, especially in the later stage of the aging process. And the divergence becomes more severe with an unreasonable equalization, such as the traditional cell voltage equalization. Equalization of the cell performance is needed to cut off the vicious circle. For the parallel module, self‐convergence of the performance exists. The better‐performing cells in the module withstand a larger current, making their performance decay faster and finally becoming consistent with the cells with worse initial performance. Meanwhile, the parallel module performance also decays significantly. Therefore, maintaining the cells’ consistency is still necessary for the parallel modules.