摘要
锂离子电池凭借其良好的性能,在新能源汽车的发展过程中备受青睐,但电池成组后因为电池的不一致性等原因会造成部分电池出现过充电现象,长期循环会影响电池的性能和寿命。本工作对某锂离子电池分别进行了4.3 V、4.4 V和4.5 V的过充循环试验,通过对新电池及过充循环后的电池进行开路电压温度系数测试、混合功率脉冲测试和等温量热测试获得了电池的熵热系数、等效直流内阻和产热功率及产热量,并利用Bernadi产热模型计算了电池的可逆热和不可逆热,综合分析过充循环对电池充放电产热特性的影响。结果表明,高的过充电压对电池性能影响更加明显,与新电池相比,4.3 V、4.4 V过充循环后的电池内阻增加并不明显,4.5 V过充循环后电池内阻最大增加了42.41%;过充循环后的电池熵热系数曲线波动更加明显且幅度随着循环电压的增大而增大;相比于放电,过充循环对电池的充电产热特性影响更明显;在电池产热的热源中,过充循环会先对可逆热产生影响,且随着过充电压的升高,可逆热占比呈现出增大的趋势。
Lithium-ion batteries are favored in developing new energy vehicles with good performance.However,due to the inconsistency of batteries and other reasons,some batteries become overcharged,and the long-term change cycle will affect their performance and life.This study conducted overcharge cycle tests of 4.3,4.4,and 4.5 V for lithium-ion batteries.Entropy coefficient,direct current resistance,heat generation power,and heat generation of the battery were obtained by conducting an open-circuit voltage temperature coefficient test,a hybrid pulse power characteristic test,and an isothermal calorimetry test on a new battery and that after an overcharge cycle.The battery's reversible and irreversible heat were calculated using the Bernadi heat generation model.The overcharge cycle's influence on the battery's heat generation characteristic was analyzed comprehensively.Results show that a high overcharge voltage has a more noticeable impact on battery performance.Compared with the new battery,the direct current resistance of that after 4.3 and 4.4 V overcharge cycles did not increase significantly.However,the maximum internal resistance of the battery rose by 42.41%after 4.5 V overcharge cycles.After the overcharge cycle,the entropy coefficient curve of the battery fluctuates even more,and the amplitude increases with an increase in the cycle voltage.Compared with the discharge cycle,the overcharge cycle more obviously influences heat generation when charging.It first affects the reversible heat in the battery's heat source.An increase in overcharge voltage causes the proportion of reversible heat to increase.
作者
常修亮
李希超
贾隆舟
韦守李
王敬豪
戴作强
郑莉莉
CHANG Xiuliang;LI Xichao;JIA Longzhou;WEI Shouli;WANG Jinghao;DAI Zuoqiang;ZHENG Lili(College of Mechanical&Electronic Engineering,Qingdao University;Power&Energy Storage System Research Center,Qingdao University;National Engineering Research Centre for Intelligent Electrical Vehicle Power System(Qingdao),Qingdao 266071,Shandong,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2023年第3期685-697,共13页
Energy Storage Science and Technology
基金
青岛市纵向科研基金项目(40518060027)。
关键词
锂离子电池
过充循环
等效直流内阻
熵热系数
电池产热
lithium-ion batteries
overcharge cycle
DC resistance
entropy coefficient
heat generation
作者简介
第一作者:常修亮(1996-),男,硕士研究生,研究方向为新能源汽车,E-mail:x_l_chang@163.com;通讯作者:郑莉莉,副教授,研究方向为新能源汽车动力电池热安全性,E-mail:llzhengqdu@163.com。
