关键词: 锂离子电池, 混合固液, 热失控, 全寿命周期

Abstract:

Hybrid solid-liquid electrolyte Li-ion batteries are energy storage devices with high energy density and high safety, which can realize industrialization in a short time. In this study, a hybrid solid-liquid electrolyte (LATP and electrolyte) battery with a high specific capacity active material (positive electrode NCM811 and negative electrode C@SiO) was investigated. An accelerating rate calorimeter and gas chromatograph were used to simulate thermal runaway and analyze gas production components of battery samples under full SOCs during the cycle life. Changes in the electrolyte content were detected using ultrasonic technology. The results show that the thermal safety of fresh batteries decreases as the charge state increases, and the proportion of combustible gas increases as the gas production increases. As the capacity decreases, thermal runaway parameters, such as the thermal runaway starting temperature, maximum heat yield rate, and gas production, decrease. The safety performance is enhanced when the capacity retention rate is 70%, which is speculated to be related to the conversion of the electrolyte into a solid electrolyte. This study preliminarily investigates the thermal runaway phenomenon of the battery in this system and provides support for the internal mechanism analysis and battery design.

Key words: lithium-ion battery, hybrid solid-liquid, thermal runaway, whole cycle life