The typical lithium-ion battery electrolyte was mixed with equal molar ratio of ethylene carbonate and methyl ethyl carbonate as solvent, added 1 mol of lithium salt LiPF6 in 1 L solvent. Theoretical calculations showed that the saturation vapor pressure concentration of typical electrolytes at 28 ℃ was at non combustible concentration; experiments verified that at 28 ℃, the mechanical sparks generated by grinding stainless steel rods with grinding wheels, the 13 kV electrical sparks from stove igniters and the burning cigarette butts could not ignite the electrolyte. The main products of electrolyte combustion in theory and practice were water and carbon dioxide, with low levels of harmful substances. The weight content of hydrofluoric acid was less than 10－5 in quality standard, was less than 4% when the electrolyte encountering with water; based on Chinese