电解液浸泡对铝塑复合膜热封强度的影响
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摘要
铝塑复合膜作为软包装锂离子电池常用的封装材料,探究其热封强度的影响因素对于优化电池的安全性能很有意义。本工作通过实验测量铝塑膜在电解液浸泡下的热封强度,讨论两种浸泡方式(完整浸泡和局部浸泡)以及不同浸泡时间的影响。结果表明,完整浸泡后试样在不同热封工况(热封温度和热封时间)下的热封强度以及破坏模式基本一致,但是其热封强度不能完全反映热封区域的强度;局部浸泡使铝塑膜的尼龙层以及铝箔层在浸泡过程中避免电解液的影响,相对完整浸泡更能反映铝塑膜的热封强度,是比较合理的浸泡方式。浸泡后试样的热封强度随着浸泡时间的增加基本呈下降趋势,对于热封温度较低、热封时间较短的试样尤为明显,而对于热封温度较高、热封时间较长的试样影响较小。实验还发现浸泡过程中电解液的p H值逐渐降低,逐渐酸化的电解液对铝塑膜热封区域的腐蚀可能是其热封强度下降的原因之一。
Aluminum plastic composite foil has become the common packaging material for soft package Li-ion battery, so it is worthy to study the influence factors of its heat-sealing strength to optimize batteries. In this article, the heat-sealing strength of Al plastic foil after soaking in the electrolyte is tested by universal testing machine to discuss the influence of soaking ways("soaking thoroughly" and "soaking partly") and soaking time. It can be concluded that the heat-sealing strength and the failure modes under the different conditions(heat-sealing temperature and heat-sealing time) for "soaking thoroughly" is almost the same, while the measured strength cannot reflect the real strength of heat-sealing zone. By contrast, the heat-sealing strength for soaking in bags can avoid the influence of the PA lay and the Al foil, so it is the better way to soak. In addition, the heat-sealing strength of Al plastic foil decreased after soaking, of which the trend is especially obvious for the specimens heat-sealed at lower heat-sealing temperature and shorter heat-sealing time. It is also found that during soaking the PH value of the electrolyte becomes lower, which may contribute also to the decreasing sealing strength.
Aluminum plastic composite foil has become the common packaging material for soft package Li-ion battery, so it is worthy to study the influence factors of its heat-sealing strength to optimize batteries. In this article, the heat-sealing strength of Al plastic foil after soaking in the electrolyte is tested by universal testing machine to discuss the influence of soaking ways("soaking thoroughly" and "soaking partly") and soaking time. It can be concluded that the heat-sealing strength and the failure modes under the different conditions(heat-sealing temperature and heat-sealing time) for "soaking thoroughly" is almost the same, while the measured strength cannot reflect the real strength of heat-sealing zone. By contrast, the heat-sealing strength for soaking in bags can avoid the influence of the PA lay and the Al foil, so it is the better way to soak. In addition, the heat-sealing strength of Al plastic foil decreased after soaking, of which the trend is especially obvious for the specimens heat-sealed at lower heat-sealing temperature and shorter heat-sealing time. It is also found that during soaking the PH value of the electrolyte becomes lower, which may contribute also to the decreasing sealing strength.
引文
[1]范洋,郭战胜,冯捷敏,等.软包装锂离子电池铝塑复合膜的热封工艺[J].储能科学与技术,2016,5(1):284-285.FAN Yang,GUO Zhansheng,FENG Jiemin,et al.Investigation on heat-sealing process of the aluminum plastic composite foil in pouch Li-ion battery[J].Energy Storage Science and Technology,2016,5(1):284-285.
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[4]PLANES E,MAROUANI S,FLANDIN L.Optimizing the heat sealing parameters of multilayers polymeric films[J].Journal of Materials Science,2011,46:5948-5958.
[5]王东升,郭永健,母军.PET/PE复合材料最佳热封工艺参数研究[J].包装工程,2012,33(19):72-74.WANG Dongsheng,GUO Yongjian,MU Jun.Research on optimal heat-seal processing parameters of PET/PE composite material[J].Packing Engineering,2012,33(19):72-74.
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[7]任宁,孙延先,吴耀辉,等.软包装锂离子电池铝塑膜的腐蚀行为[J].有色金属工程,2015,5(5):29-32.REN Ning,SUN Yanxian,WU Yaohui,et al.Al-plastic film corrosion behavior of soft-packing lithium-ion battery[J].Nonferrous Metals Engineering,2015,5(5):29-32.
[8]GB/T 22638.7—2008.Test methods for aluminum and aluminum alloy foils.Part 7:Determination of heat seal strength[S].2008.
[2]秦楠,周正发,谢文汇.锂离子电池软包装用CPP薄膜热封特性的研究[J].包装工程,2009,30(11):4-6.QIN Nan,ZHOU Zhengfa,XIE Wenhui.Study of heat-seal properties on CPP film for flexible packaging of lithium-ion battery[J].Packing Engineering,2009,30(11):4-6.
[3]秦楠.软包装锂离子电池材料的制备和性能[D].合肥:合肥工业大学,2010.QIN Nan.Preparation and properties of flexible packaging materials for lithium-ion batteries[D].Hefei:Hefei University of Technology,2010.
[4]PLANES E,MAROUANI S,FLANDIN L.Optimizing the heat sealing parameters of multilayers polymeric films[J].Journal of Materials Science,2011,46:5948-5958.
[5]王东升,郭永健,母军.PET/PE复合材料最佳热封工艺参数研究[J].包装工程,2012,33(19):72-74.WANG Dongsheng,GUO Yongjian,MU Jun.Research on optimal heat-seal processing parameters of PET/PE composite material[J].Packing Engineering,2012,33(19):72-74.
[6]MIHINDUKULASURIYA S,LIM L T.Effects of liquid contaminants on heat seal strength of low-density polyethylene film[J].Packaging Technology and Science,2012,25:271-284.
[7]任宁,孙延先,吴耀辉,等.软包装锂离子电池铝塑膜的腐蚀行为[J].有色金属工程,2015,5(5):29-32.REN Ning,SUN Yanxian,WU Yaohui,et al.Al-plastic film corrosion behavior of soft-packing lithium-ion battery[J].Nonferrous Metals Engineering,2015,5(5):29-32.
[8]GB/T 22638.7—2008.Test methods for aluminum and aluminum alloy foils.Part 7:Determination of heat seal strength[S].2008.