软包锂离子电池铝塑膜的热封性能研究

Study on heat sealing performance of aluminum-plastic film for flexible packaging lithium ion battery

选取40μm流延聚丙烯热封层铝塑膜(1^#样品)、80μm流延聚丙烯热封层铝塑膜(2^#样品)和80μm接枝改性PP热封层铝塑膜(3^#样品)作为研究对象,在不同热封温度、热封时间、热封压力、热封层厚度和热封层种类的条件下,对3种不同软包锂离子电池铝塑膜进行热封研究。利用万能试验机和扫描电镜等,对3种不同铝塑膜的热封强度和热封结合界面进行分析。结果表明,3种不同铝塑膜的最佳热封工艺均为热封温度为230℃,热封时间为12 s,热封压力为1.0 MPa。1^#样品的热封强度最高仅为98.9 N/15 mm;3^#样品的热封强度最高为114.3 N/15 mm;2^#样品的热封强度最高可达144.4 N/15 mm。在0.5~1.0 MPa的范围内,热封压力对铝塑膜热封强度的影响不显著,热封温度和热封时间成为影响样品热封强度的主要因素。在相同的热封条件下,CPP热封层的热封效果要明显好于PP-g-PGMA热封层。热封剥离失效界面的研究表明,剥离实验失效模式为界面破坏和剥离破坏两种破坏模式并存,CPP与铝箔间的界面没有紧密机械啮合,如果对铝箔进行表面处理,增加铝箔与CPP间的机械结合力,可能会成为提高铝塑膜热封强度的有效手段之一。

Aluminum-plastic film of 40μm tape casting polypropylene(1^#sample),80μm tape casting polypropylene(2^#sample)and 80μm grafted modified polypropylene(3^#sample)were selected as the research objects.Three kinds of soft-coated lithium ion battery aluminium-plastic film were reserached under different heat-sealing temperature,time,pressure,thickness and types of heat-sealing layer.The heat sealing strength and bonding interface of three different aluminium-plastic films were analyzed by universal testing machine and scanning electron microscope.The results showed that the optimum heat sealing process for three different aluminium-plastic films was the heat sealing temperature of 230℃,the heat sealing time of 12 s and the heat sealing pressure of 1.0 MPa.The highest heat sealing strength of 1^#sample was 98.9 N/15 mm;that of 3^#sample was 114.3 N/15 mm;and that of 2^#sample was 144.4 N/15 mm.In the range of 0.5-1.0 MPa,the effect of heat sealing pressure on the heat sealing strength of the aluminium-plastic film wasn’t significant.The heat sealing temperature and time were the main factors affecting the heat sealing strength of the sample.Under the same heat sealing conditions,the heat sealing effect of CPP heat sealing layer was better than that of PP-g-PGMA heat sealing layer.The research on the interface of hot-seal peeling failure showed that the failure modes of peeling experiment were interfacial failure and peeling failure.The interface between CPP and aluminium foil wasn’t closely mechanically meshed.If the aluminium foil is surface treated and the mechanical bonding force between aluminium foil and CPP is increased,it may become one of the effective means to improve the heat-seal strength of aluminium-plastic film.