添加剂、隔膜对锂离子电池过充性能的影响

Effects of additive and separator on overcharge performance of lithium-ion battery

采用电聚合添加剂环己基苯、联苯来改善以钴酸锂为正极材料的高容量锂离子方形电池过充性能(1 C 10 V、3 C4.8 V),并探讨隔膜性能对电池过充测试的影响。实验发现,1 C 10 V过充测试,电解液中添加环己基量增加时能提高电池过充测试的通过率,添加5%(质量分数)环己基苯+5%(质量分数)联苯时能对电池起到良好的保护效果,但对3 C 4.8V所起的作用不大;具有较大的穿刺强度的隔膜能对电池3 C 4.8 V过充测试起到良好的保护作用;隔膜型号与添加剂对电池循环厚度及容量保持率均有一定的影响,加入添加剂后电池循环性能下降,而良好的隔膜性能可提高电池循环性能。

The elctropolymerizatj0n additives cyclohexylbenzene（CHB） and biphenyl（BP） were added to the electrolyte to improve the overcharge performance（1 C 10 V, 3 C 4.8 V） of prismatic lithium-ion battery with high capacity. Also the effect of separator on overcharge performance was investigated. The results of tests show that the pass rate of 1 C 10 V overcharge test is increased by adding CHB and BP, the battery can be protected in 1 C 10 V overcharge test with 5% CHB＋ 5% BP, and in 3 C 4.8 V overcharge test with the separator which owned higher puncture strength. Meanwhile the capacity retention and thickness after cycling were related to the additives and the separator. Additives were resulted in cycle performance degradation, while the performance of cycling could be improved by the good property of separator.