Prediction of Swelling of Polypropylene Separators and Its Effect on the Lithium-Ion Battery Performance
Prediction of Swelling of Polypropylene Separators and Its Effect on the Lithium-Ion Battery Performance
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DOI：
10.1021/acsapm.2c02074
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发表时间：
2023-02
影响因子：
5
通讯作者：
A. Maksimov;Marcos Molina;O. Maksimova;G. Gor
中科院分区：
文献类型：
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作者：
A. Maksimov;Marcos Molina;O. Maksimova;G. Gor
锂离子电池的安全性和可靠性取决于多孔隔膜，其中许多隔膜由聚合物材料制成，如聚丙烯。隔膜与电池中使用的有机电解质溶剂之间的有利相互作用通常引起隔膜溶胀。膨胀会增加电池的电阻，并伴随着隔膜的塑化，这也会影响电池的性能。在这里，我们提出了一个模型的基础上Flory的理论的聚合物溶液，它可以预测的基础上的聚合物-溶剂相互作用的Flory-Huggins参数的多孔聚合物隔膜的溶胀。尽管聚合物结构的复杂性，仅引入两个额外的参数提供了模型的预测能力。这两个参数可以基于在两种不同溶剂中的隔膜溶胀的实验测量来获得;该模型还需要Flory-Huggins参数作为输入，其可以基于给定聚合物-溶剂对的CRAAC-FV基团贡献方法来计算。我们说明了这个模型的适用性，最近的实验数据在各种溶剂中的聚丙烯隔板的溶胀。我们还表明了一个简单的关系之间的隔膜膨胀和电池电阻的增加。我们的模型可用于快速评估各种聚合物-溶剂对在锂离子电池中的应用。
The safety and reliability of lithium-ion batteries depend on porous separators, many of which are made of polymer materials, such as polypropylene. Favorable interactions between a separator and organic electrolyte solvents used in the batteries often induce separator swelling. Swelling increases the electric resistance of the cell and is accompanied by plasticization of the separator, which also affects the battery’s performance. Here we propose a model based on Flory’s theory of polymer solutions which can predict the swelling of a porous polymer separator based on the Flory–Huggins parameter for polymer–solvent interactions. Despite the complexity of the polymer structure, introducing only two additional parameters provides predictive capability for the model. These two parameters can be obtained based on experimental measurements of separator swelling in two different solvents; the model also requires the Flory–Huggins parameter as an input, which can be calculated based on the UNIFAC-FV group contribution method for a given polymer–solvent pair. We illustrated the applicability of this model to recent experimental data on the swelling of polypropylene separators in various solvents. We also showed a simple relation between the separator swelling and an increase in cell resistance. Our model can be used for a quick assessment of various polymer–solvent pairs for application in lithium-ion batteries.