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摘要
随着储能技术的快速发展和应用普及,开发长循环且高安全特性的磷酸铁锂(LiFePO4)电芯显得尤为重要。以湿法双向拉伸聚乙烯(PE)隔膜为基膜,通过Al2O3辊涂、聚偏二氟乙烯(PVDF)旋转喷涂以及Al2O3辊涂+PVDF旋转喷涂得到PE+Al2O3、PE+PVDF、PE+Al2O3+PVDF复合隔膜。将隔膜分别与正负极片卷绕,得到储能电芯,研究了Al2O3辊涂涂层、PVDF喷涂涂层对隔膜、极组和电芯综合性能的影响。结果表明:Al2O3涂层能够显著提高隔膜的热稳定性;PVDF涂层能够增强极片与隔膜的粘接性能,维持极组形状,抑制极片褶皱;针刺测试过程中,使用PE+Al2O3复合隔膜的电芯不起火,不爆炸;使用PE+Al2O3+PVDF复合隔膜的电芯综合电化学性能最佳,在2.0P高功率和-20℃条件下放电容量高达276.1Ah和249.5Ah,经过500次高温循环后放电容量仍达到275.6Ah,显著优于其他隔膜。
Abstract
With the rapid development and application popularization of energy storage technology,it is significant to develop the LiFePO4 cells with long cycling life and high safety properties.In this work,the wet biaxial stretching polyethylene (PE) was acted as basement separator to obtain the PE+Al2O3,PE+PVDF and PE+Al2O3+PVDF composite separators via Al2O3 roller coating,PVDF spray coating and Al2O3 roller coating+PVDF spray coating technologies,respectively.These separators were severally wound with cathode and anode plates to form the energy storage cells.The influences of Al2O3 roller coating layer and PVDF spray coating layer on the overall performance of separators,electrode assembly and cells were studied.It was found that Al2O3 coating layer could obviously enhance the thermostability of separators,PVDF coating layer increased the adhesive strength between electrodes and separators,maintained the shape of electrode assembly and further suppressed the formation of electrodes folds.In addition,the cells with the Al2O3 coating layer covered separators could successfully pass the Nail penetration test without fire or explosion.The cells with PE+Al2O3+PVDF separator delivered the optimal overall electrochemical properties with the high discharging capacities of 276.1Ah and 249.5Ah at 2.0P large power and -20℃ low temperature.The discharge capacity still reached 275.6Ah after 500 cycles at high-temperature,which was significantly superior to those of other separators.
关键词
聚乙烯隔膜
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Al2O3涂层
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PVDF涂层
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安全性能
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电化学性能
Key words
polyethylene separator
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Al2O3 coating layer
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PVDF coating layer
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safety performance
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electrochemical properties
聚乙烯隔膜及涂层对LiFePO4电芯性能的影响研究[J].
化工新型材料, 2025, 53(12): 168-172 DOI:10.19817/j.cnki.issn1006-3536.2025.12.005
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