Overshoot gas-production failure analysis for energy storage battery with 5 Ah lithium iron phosphate pouch cell

Abstract

In the context of the burgeoning new energy industry, lithium iron phosphate (LiFePO₄)-based batteries have gained extensive application in large-scale energy storage. Nevertheless, the inherent flammability of the traditional ester liquid electrolyte renders the thermal runaway of LiFePO₄ batteries a critical scientific issue under overcharge circumstances. This research centers on the gas-production analysis and corresponding failure mechanism of 5Ah LiFePO₄ pouch batteries subjected to diverse overcharge conditions. By employing in-situ differential electrochemical mass spectrometry (in-situ DEMS), gas chromatography, and in-situ thermocouple monitoring apparatus, an in-depth exploration was conducted into the evolution of characteristic gases and the concomitant temperature alterations during battery failure. The findings reveal that at relatively low overcharge voltages, the hydrogen content exhibits a significant variation; conversely, at higher overcharge voltages, the contents of carbon dioxide and carbon monoxide manifest a notable increase. These results hold substantial implications for the fabrication of relevant early warning devices and the prompt alert of potential hazards, thereby facilitating a more profound comprehension of the overcharge gas-production behavior of LiFePO₄ batteries and augmenting the safety and dependability of energy storage systems.