软包锂电池在适当压力下的膨胀及寿命研究  

Battery expansion and life study of soft-packaged lithium batteries under appropriate pressure

作　　者：张军[1] 曾云路 邹舜章 罗青 ZHANG Jun;ZENG Yun-lu;ZOU Shun-zhang;LUO Qing(College of Mechanical and Vehicle Engineering,Hunan University,Changsha Hunan 410082,China;Hunan King-Co New Energy Co.,Ltd.,Changsha Hunan 410000,China)

机构地区：[1]湖南大学机械与运载工程学院,湖南长沙410082 [2]湖南丰源业翔晶科新能源股份有限公司,湖南长沙410000

出　　处：《电源技术》2019年第10期1641-1644,共4页Chinese Journal of Power Sources

摘　　要：电动汽车软包锂离子电池在构成模块成组时必不可少地需要一定的压力来固定约束电池,但是压力过大或过小会对电池造成一定的损害。通过对软包锂离子电池在恒压状态下进行充放电循环测试,分析实验数据并对比不同压强下的几个电池组,结果表明施加69kPa的压强时有利于延长电池寿命。对比不同寿命阶段下电池的放电能力曲线,施加适当压力的电池即使经过2000次循环依旧保持良好的放电能力,加压能让电芯接触更加紧密。通过观测一个单次循环中压力的变化,表明电池充电时膨胀,放电时恢复。同时通过实验数据表明不同寿命阶段电池各个部位的膨胀程度也不同,负极近极耳端膨胀比较明显,负极膨胀是影响电池膨胀的主要因素,电池内部的不可逆膨胀主要发生于寿命前中期,经2000次循环后电池厚度膨胀了2.7%。Lithium batteries for electric vehicle needs certain pressure to fix and restrain the batteries when forming modules,but too much or too little pressure will cause certain damage to the battery.Through the test of soft package lithium battery charge and discharge cycle under the constant pressure,the experimental data were analyzed and the several battery packs under different pressure were compared.The results show that applying 69 kPa pressure helps extend battery life.By comparing the discharge capacity curves of the batteries in different life stages,the batteries with appropriate pressure can maintain good discharge capacity after 2 000 cycles,and the contact between the batteries can be more closely under pressure.By observing the change of pressure in a single cycle,it shows that the battery expands when charging and recovers when discharging.At the same time,the experimental data show that the expansion degree of each part of the battery is different in different life stages.The expansion of the near-pole ear of the negative pole is obvious.The expansion of the negative pole is the main factor affecting the expansion of the battery.The irreversible expansion of the battery mainly occurs in the early and middle life stages.After 2 000 cycles,the thickness of the battery expands by 2.7%.

关 键 词：软包锂离子电池 压力 电池寿命 充放电循环 电池膨胀 

分 类 号：TM912[电气工程—电力电子与电力传动]