Reliable test by accelerating for gas evolution in cathode materials of lithium-ion batteries

Abstract

Lithium -ion batteries are widely used in modern electronic devices and Electric Vehicles (EVs) and play an important role in various applications, but fire and explosion accidents continue to occur in Energy Storage Systems (ESSs) and EVs, which is an issue. Due to the material characteristics of the Li -ion battery, when charging and discharging are repeated, gas is generated not only due to structural changes inside the cell, but also due to various external factors. This can lead to an explosion accident of the battery cell. Therefore, gas generation in batteries is considered an essential problem to be solved for battery safety. However, accurate gas generation comparisons are possible only when the gas generation conditions and processes of the battery are established, and the conditions under which gas can be uniformly generated in the battery have not yet been investigated. According to previous studies, the main causes of gas generation are considered as follows. 1) Operating at high voltage range, 2) Operating at high temperature and 3) H2O present inside the cell. Therefore, this study conducted a study on the possibility of reproducing the above tree gas generations, which are considered to be a major cause of gas generation. Gas generation in high voltage operation and high temperature operation was confirmed, but there was no reliable reproducibility. On the other hand, it was confirmed that H2O inside the cell reproducibly generates gas. In addition, compared to the Al coating sample, a surface treatment that suppresses gas generation caused by HF generation by H2O, it was reliably confirmed that more than 10% of gas generation by H2O was prevented.