三问三解 | 锂电池如何灭火？

Core Viewpoint - The recent issues surrounding multi-brand power banks, including recalls, removal from e-commerce platforms, and safety concerns regarding lithium battery cells, have sparked significant public discussion about the safety and management of lithium batteries [1][3]. Group 1: Lithium Battery Characteristics - Lithium batteries, including both ternary lithium and lithium iron phosphate batteries, are categorized as chemical batteries composed of positive and negative electrodes, electrolyte, and separator [1]. - The positive electrode materials include lithium cobalt oxide, lithium manganese oxide, nickel cobalt aluminum oxide, ternary materials, and lithium iron phosphate, while lithium serves as the active material in the negative electrode [1][3]. Group 2: Causes of Thermal Runaway - During normal charge and discharge cycles, lithium ions move between the electrodes, but factors such as usage time, charge/discharge cycles, and temperature differences can increase internal resistance [3]. - External factors like overcharging, over-discharging, short circuits, and high temperatures can lead to chemical reactions within the battery, potentially resulting in thermal runaway, where internal heat cannot be dissipated, leading to fire or explosion [3][4]. Group 3: Firefighting Methods for Lithium Battery Fires - Once thermal runaway occurs, high temperatures can decompose the electrolyte, producing flammable gases like hydrogen and methane, which can ignite without oxygen [5]. - Water is considered one of the most effective extinguishing agents for lithium battery fires, as it can absorb heat through evaporation, lowering the battery's temperature and preventing further thermal runaway [9]. - Perfluorohexane is also effective in extinguishing battery fires due to its cooling, oxygen-isolating, and chemical suppression properties, although it is more expensive [11].