陶瓷隔膜对锂离子电池低温性能的影响

Effect of ceramic separators on low temperature performance of Li-ion battery

以普通聚烯烃隔膜为空白样,对比干法和湿法聚烯烃基材制备的陶瓷隔膜的本征性能,包括透气度、微观形貌、孔隙率和离子电导率等。干法陶瓷隔膜、湿法陶瓷隔膜和普通隔膜的透气度分别为168 s/100 ml、224 s/100 ml和555 s/100 ml,离子电导率分别为1. 115 m S/cm、0. 735 m S/cm和0. 467 m S/cm。分别用3种隔膜制备容量4. 5 Ah、比能量233 Wh/kg的软包装锂离子电池。在-40℃下,以4. 0 C连续放电,干法陶瓷隔膜、湿法陶瓷隔膜以及普通隔膜软包装试验电池的容量保持率分别是额定容量的81. 8%、62. 6%和51. 1%。与普通聚烯烃隔膜相比,陶瓷隔膜可提高锂离子电池在超低温(-40℃)下的倍率性能。以干法聚烯烃膜为基材的陶瓷隔膜对电池超低温倍率性能的增效作用,高于以湿法聚烯烃膜为基膜的陶瓷隔膜。

Compared with the ordinary polyolefin separator,the intrinsic properties of ceramic separator prepared by dry process based film and wet process based film were researched,including air permeability,micro-morphology,porosity and ion conductivity.For ceramic separators with dry process based film and wet process based film as well as ordinary polyolefin separator, the air permeability was 168 s/100 ml,224 s/100 ml and 555 s/100 ml,the ion conductivity was 1.115 mS/cm,0.735 mS/em and 0.467 mS/em,respectively.Soft packing batteries were prepared with three types of separators,the capacity value was 4.5 Ah,the specific energy was 233 Wh/kg.The cells prepared by dry process based film ceramic separator,wet process based film ceramic separator and ordinary polyolefin separator could respectively deliver 81.8%,62.6% and 51.1% of the nominal capacity at 4.0 C (22.5 A)under -40℃.The ceramic separator with dry process based film could improve Li-ion battery rate performance on low temperature (-40℃),which was better than that with wet process based separator.