首页|锂离子电池用PET-Cu复合集流体拉伸性能研究

锂离子电池用PET-Cu复合集流体拉伸性能研究

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  • 国家科技期刊平台
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随着锂离子电池技术的不断发展,复合集流体因其具有显著提升电池能量密度和安全性高等优势而引起了产业界的广泛关注.而复合集流体的力学性能可靠性是保证其安全服役的前提,为此,本文针对商业用聚对苯二甲酸乙二醇酯-铜(PET-Cu)复合集流体的拉伸性能开展了系统性的研究.利用扫描电镜、激光共聚焦显微镜、X射线衍射等技术手段对复合集流体材料的表面形貌、微观结构及拉伸断裂行为进行了表征与分析.借助有限元模拟分析了不同几何形状试样在拉伸过程中的应力分布状态;通过数字图像相关技术辅助的拉伸实验研究了取样方向、应变速率及试样几何尺寸对PET-Cu复合集流体拉伸性能的影响规律,并对其应变测量进行了校正.结果表明,采用狗骨状试样并进行应变校正可以更准确地评估复合集流体的拉伸性能;PET-Cu复合集流体的拉伸性能表现出试样取样方向相关性和应变速率敏感性.此外,PET-Cu复合集流体的断裂伸长率表现出明显的试样几何尺寸效应,通过引入几何尺寸系数K可以对不同尺寸的试样拉伸性能进行合理的预测.本研究为聚合物复合集流体实际应用提供了理论依据与可靠性的论证,也为相关试验标准的建立提供了参考,有望推动高性能锂离子电池的开发.
Study on the tensile properties of PET-Cu composite current collectors for lithium-ion batteries
With the advancement of lithium-ion battery technology,composite current collectors have garnered significant interest due to their role in enhancing battery energy density and safety.The mechanical performance of composite current collectors is crucial for ensuring their reliable operation.This study systematically investigates the mechanical properties of commercial polyethylene terephthalate-copper(PET-Cu)composite current collectors.The surface morphology,microstructure,and tensile fracture behavior of the PET-Cu composite were characterized using scanning electron microscopy,laser confocal microscopy,and X-ray diffraction.Stress distribution in dog-bone-shaped and long-strip-shaped samples during tensile testing was analyzed and compared through finite element simulation.The effects of sampling direction,strain rate,and specimen geometry on the tensile properties were assessed using tensile tests supported by digital image correlation technology.The dog-bone-shaped samples were found to be more effective in evaluating mechanical properties,as their transition arcs alleviate stress concentration.The mechanical properties along the machined direction proved superior to those along the transverse directions,attributed to the orientation structures of the matrix.Higher loading strain rates enhanced the overall mechanical properties of the current collector.While the geometric size of the samples had minimal impact on strength,it significantly affected elongation at fracture.The primary deformation mechanism during tensile testing was identified as dislocation slip,with surface defects such as holes acting as favorable sites for crack initiation.Considering these factors is essential when testing the tensile properties of PET-Cu composite current collectors.This research provides a theoretical foundation and reliability demonstration for the practical application of composite collectors and offers a reference for developing relevant testing standards.This study's findings are poised to advance the development of lithium-ion batteries with improved energy density and safety.

composite current collectortensile propertiesfinite element simulationdigital image correlation techniquestrain rate sensitivitygeometric size effect

肖峰、程福来、罗雪梅、张广平、张滨

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东北大学材料科学与工程学院,材料各向异性与织构教育部重点实验室,辽宁 沈阳 110819

中国科学院金属研究所,沈阳材料科学国家研究中心,辽宁 沈阳 110016

中国科学技术大学材料科学与工程学院,辽宁 沈阳 110016

复合集流体 拉伸性能 有限元模拟 数字图像相关技术 应变速率敏感性 几何尺寸效应

国家自然科学基金面上项目中国科学院先导专项(B类)

52071319XDB0510303

2024

10.19799/j.cnki.2095-4239.2024.0056

储能科学与技术
化学工业出版社

储能科学与技术

CSTPCD北大核心
影响因子：0.852
ISSN：2095-4239
年,卷(期)：2024.13(6)
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