锂离子电池负极极片的力学性能及其影响因素
|
摘要
锂离子电池极片的柔性和强度直接影响其寿命,极片的力学性能受集流体和粘接剂的影响。通过小型拉伸机、扫描电子显微镜(SEM)、X射线衍射(XRD)和激光共聚焦显微镜等手段,对集流体和负极极片的力学性能、表面形貌、铜箔的表面粗糙度等进行了研究。结果表明,集流体的抗拉强度为121 MPa、断后伸长率为1.9%;负极极片的抗拉强度为15 MPa、断后伸长率为1.7%。极片涂覆层的弹性模量为1 GPa,说明粘结剂的柔性较差。极片涂覆层形貌呈片状,结构均匀且空隙少。铜箔表面粗糙度较大,其光面和毛面粗糙度差异明显。降低粘接剂的弹性模量是提高负极极片柔性、减小集流体辊压变形的关键。
Flexibility and strength of the lithium-ion battery electrode directly affect its service life,and the mechanical properties of the electrode are affected by the current collector and binder.The mechanical properties,surface morphology of current collector and negative plate as well as the surface roughness of copper foil were studied by means of miniature tensile testing machine,scanning electron microscopy(SEM),X-ray diffraction(XRD) and laser confocal microscopy.The results showed that tensile strength of the copper foil was 121 MPa,elongation was 1.9%;and tensile strength of the negative plate was 15 MPa,elongation was 1.7%.The elastic modulus of the coating was 1 GPa,which showed that the flexibility of binder was poor.The coating of the negative plate was flaky,and possessed uniform structure and a few interspaces.The overall roughness of copper foil was large,and exhibited obvious difference in smooth surface and rough surface.Reducing the elastic modulus of the binder is the key to improve the flexibility of the negative plate and to reduce the rolling deformation of the current collector.
Flexibility and strength of the lithium-ion battery electrode directly affect its service life,and the mechanical properties of the electrode are affected by the current collector and binder.The mechanical properties,surface morphology of current collector and negative plate as well as the surface roughness of copper foil were studied by means of miniature tensile testing machine,scanning electron microscopy(SEM),X-ray diffraction(XRD) and laser confocal microscopy.The results showed that tensile strength of the copper foil was 121 MPa,elongation was 1.9%;and tensile strength of the negative plate was 15 MPa,elongation was 1.7%.The elastic modulus of the coating was 1 GPa,which showed that the flexibility of binder was poor.The coating of the negative plate was flaky,and possessed uniform structure and a few interspaces.The overall roughness of copper foil was large,and exhibited obvious difference in smooth surface and rough surface.Reducing the elastic modulus of the binder is the key to improve the flexibility of the negative plate and to reduce the rolling deformation of the current collector.
引文
[1]闫金定.锂离子电池发展现状及其前景分析[J].航空学报,2014,35(10):2766-2735.
[2]王高军.新型二次化学电源的探索[D].上海:复旦大学,2008.
[3]杜飞虎.高容量锂离子电池负极材料的制备及性能研究[D].上海:上海交通大学,2015.
[4]李泓,吕迎春.电化学储能基本问题综述[J].电化学,2015,21(5):412-424.
[5]时志强,樊丽萍,王成扬.商业化的锂离子电池石墨负极材料的研究进展[J].炭素,2006(1):3-7.
[6]XU J Y,TANAKA H,KURIHARA M,et al.Influence of active surface on electrochemical properties of mesocarbon microbeads powders[J].Journal of Power Sources,2004,133(2):260-262.
[7]柴丽莉.锂离子电池石墨电极新型粘结剂的研究[D].苏州:苏州大学,2013.
[8]谭凯.锂离子电池集流体用多孔铜箔的制备与研究[D].北京:清华大学,2009.
[9]DANIEL C,BESENHARD J O.Handbook of battery materials[M].2nd ed.Weinheim:Wiley-VCH,2011.
[10]ZHANG Q T,YU Z L,DU P,et al.Carbon nanomaterials used as conductive additives in lithium ion batteries[J].Recent Patents on Nanotechnology,2010,4(2):100-110.
[11]LIU G,ZHENG H H,KIM S,et al.Effects of various conductive additive and polymeric binder contents on the performance of a lithium-ion composite cathode[J].Journal of Electrochemical Society,2008,155(12):887-892.
[12]CHO G B,LEE B K,SIN W C,et al.Effects of Cu current collector as a substrate on electrochemical properties of Li/Si thin film cells[J].Journal of Materials Science,2006,41(2):313-315.
[13]朱建宇,冯捷敏,王宇晖,等.锂离子电池用铜箔集流体的力学性能分析[J].储能科学与技术,2014,3(4):360-364.
[14]吕欣蕊.电沉积铜箔的工艺参数和拉伸性能研究[D].天津:天津大学,2010.
[15]韩立朝,彭华.工程力学[M].武汉:武汉大学出版社,2006.
[2]王高军.新型二次化学电源的探索[D].上海:复旦大学,2008.
[3]杜飞虎.高容量锂离子电池负极材料的制备及性能研究[D].上海:上海交通大学,2015.
[4]李泓,吕迎春.电化学储能基本问题综述[J].电化学,2015,21(5):412-424.
[5]时志强,樊丽萍,王成扬.商业化的锂离子电池石墨负极材料的研究进展[J].炭素,2006(1):3-7.
[6]XU J Y,TANAKA H,KURIHARA M,et al.Influence of active surface on electrochemical properties of mesocarbon microbeads powders[J].Journal of Power Sources,2004,133(2):260-262.
[7]柴丽莉.锂离子电池石墨电极新型粘结剂的研究[D].苏州:苏州大学,2013.
[8]谭凯.锂离子电池集流体用多孔铜箔的制备与研究[D].北京:清华大学,2009.
[9]DANIEL C,BESENHARD J O.Handbook of battery materials[M].2nd ed.Weinheim:Wiley-VCH,2011.
[10]ZHANG Q T,YU Z L,DU P,et al.Carbon nanomaterials used as conductive additives in lithium ion batteries[J].Recent Patents on Nanotechnology,2010,4(2):100-110.
[11]LIU G,ZHENG H H,KIM S,et al.Effects of various conductive additive and polymeric binder contents on the performance of a lithium-ion composite cathode[J].Journal of Electrochemical Society,2008,155(12):887-892.
[12]CHO G B,LEE B K,SIN W C,et al.Effects of Cu current collector as a substrate on electrochemical properties of Li/Si thin film cells[J].Journal of Materials Science,2006,41(2):313-315.
[13]朱建宇,冯捷敏,王宇晖,等.锂离子电池用铜箔集流体的力学性能分析[J].储能科学与技术,2014,3(4):360-364.
[14]吕欣蕊.电沉积铜箔的工艺参数和拉伸性能研究[D].天津:天津大学,2010.
[15]韩立朝,彭华.工程力学[M].武汉:武汉大学出版社,2006.