锂离子电池电解液环境友好研究

典型的锂离子电池电解液采用等摩尔比例的碳酸乙烯酯和碳酸甲乙酯构成的混合溶剂，每 1 L混合溶剂加 1 mol 的锂盐(LiPF6)。理论计算表明，典型比例的电解液在 28 ℃ 的饱和蒸气压浓度为不燃浓度。试验测试证明，在 28 ℃ 下，砂轮打磨不锈钢棒产生的机械火花、灶具点火器的 13 kV 电火花、燃烧的烟头不能点燃典型比例的电解液。在理论推算和实践中，电解液燃烧的主要产物是水和二氧化碳，有害物质含量少。电解液品质要求：氢氟酸质量分数不超过 10－5，遇水形成氢氟酸质量分数不超过 4%。在《危险废物鉴别标准通则》(GB 5085.7—2019)中，这种低浓度的氢氟酸为环境无害物质。根据《建设项目环境风险评价技术导则》(HJ 169—2018)：要选择容积最大的单桶溶剂来计算形成的氢氟酸，不得超过 1 t 的临界值。电解液桶有两种容积，即每桶 200 kg 或每桶 1 t，泡水形成的氢氟酸为 8 kg 或 40 kg，低于临界值 1 t，对应环境风险潜势为 I，评价等级为简单分析方式。

Environmental Friendliness Study of Electrolyte of Lithium-ion Battery

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