18650高容量锂离子电池研制

摘要

采用高镍材料作为电池正极制作了18650型圆柱锂离子电池（0．5C 放电标称容量为2800 mAh），并对该材料扣式电池与18650锂离子电池性能进行了测试。结果显示：高镍材料扣式电池首次充放电效率为88．7％；Li 氧化覆盖整个氧化峰范围（3．7～5．0 V），同时4．25 V 时 Ni2＋/Ni4＋电对氧化，5．0 V 处为 Co3＋/Co4＋的氧化，并且反应开始时优先发生 Ni 的氧化，随着电位增大，发生 Co 的氧化。高镍材料18650锂离子电池0．5 C、1．0 C、2．0 C 放电容量分别是0．2 C 时的99．89％、99．26％、97．38％，能够满足电池对于快充快放的使用要求；电池0．5 C 充电1 C 放电20周、100周、200周、450周对应容量保持率分别为98．40％、94．74％、87．62％、82．22％。低倍率（0．5C）时，常规结构18650电池与本实验结构电池的散热效果相当，随着放电倍率增大，两种结构散热效果温度差值也增大。%18650 cylindrical Li-ion battery was made with nickel-rich composite material as cathode in this paper.And the battery’s nominal capacity was 2 800 mAh at 0.5 C.The performance of nickel-rich composite button cell and 18650 type full battery was tested.The testing results showed that,the first charge/discharge rate of the composite materials of cobaltickel/man-ganese was 88.7%,and Li oxidation covered the oxidation peak from 3.7 V to 5.0 V,and the oxidation of Ni2 + to Ni4+ at 4.25 V,while Co3 + oxidized to Co4+ at 5.0 V,Ni oxidation preferen-tially occurred at the beginning of the reaction.With the increasing of potential,the Co3 + subse-quently oxidized.For the nickel-rich composite 18650 type full battery,the discharge of 0.5C, 1.0 C,2.0 C rate contrasting to 0.2C was 99.89%,99.26%,97.38%,respectively.And it can meet the requirements of fast charge/discharge.The capacity retention rate of 18650 type full battery after (0.5C charge /1 C discharge)20 cycles,100 cycles,200 cycles,475 cycles,was 98.40%,94.74%,87.62%,82.22% ,respectively.At low discharge rate,there was no marked difference between the traditional structure 18650 battery and the tested nickel-rich bat-tery.And with the increasing of the discharge rate,the temperature difference of two structure battery increased.