Investigation of the Temperature Behavior of Silicon-Rich Multilayer Pouch Lithium-Ion Battery Cells and Its Effect on Cycle Life and Rate Capability

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2024-02; no. 10; p. 4969
• Main Authors: Bosch, Hannah, Diller, Felix
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society, Inc 22.11.2024
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2024-02104969mtgabs

Due to its high energy density and fast charge capability, silicon is an excellent active material, especially in electrical vehicles (EV) applications. The fast charging capability can be reasoned through its higher potential against Li/Li + when compared to graphite, reducing the risk of Li-plating. As a result of the volume change of silicon during the (de-) lithiation processes, a continuous reformation of the solid electrolyte interface (SEI) takes place. FEC is used as an additive or as a co-solvent to improve the SEI formation. It reported in literature that FEC decomposes at elevated temperatures starting from 45°C [1]. As such elevated temperatures can easily be reached, especially during the charge step in applications where bigger battery formats are used, the temperature behavior of high silicon wt% Lithium-Ion Batteries should be investigated more thoroughly. To the best of our knowledge, a focus on the temperature behavior of multilayer pouch cells (MLP) with a very high silicon content (70wt%) has not been subject of research so far. Therefore, this study gives important insights into the electrochemical and thermal behavior of silicon within bigger battery formats. MLP cells with 5 Ah were built and tested for their rate capabilities and their temperature behavior. The cells consisted of 70wt% of silicon as the anode material and a high nickel cathode material. Rate tests were conducted at 10 °C, 25 °C and 40 °C with MLP cells. The resistances were measured at three States of Charge points 25%, 50%, and 75% to investigate the temperature impact on the resistance. Additionally, the cycle lifetimes of the MLP cells were investigated at different fast charging C-rates (C/2, 2C, 5C) until 80% State of Health (SoH) at 25 °C. These results give important information on the performance of silicon based 5Ah lithium-ion batteries in a bigger format. The temperature behavior needs to be understood, as the battery‘s thermal management has to be adapted accordingly, especially for application purposes such as EVs. The study is investigated in the project “CAESAR”, funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) under grant number 03El3046F. We thank BASF SE for the NCM cathode material, Wacker Chemie AG for the silicon anode material and E-Lyte for the electrolyte. [1] T. Teufl, D. Pritzl, L. Hartmann, S. Solchenbach, M. Mendez, H. Gasteiger, “Implications oft he Thermal Stability of FEC-Based Electrolytes for Li-Ion Batteries”, J. Electrochem. Soc. , 2023, 170 , 020531, DOI: 10.1149/1945-7111/acbc52.