储能用LiFePO_(4)锂离子电池过放电失效分析  

Analyses of failure by over-discharge of LiFePO_(4) Li-ion battery for energy storage

作　　者：顾昊 张松通 胡海良 祝夏雨 明海[2] GU Hao;ZHANG Songtong;HU Hailiang;ZHU Xiayu;MING Hai(College of Chemical Engineering,Guizhou Minzu University,Guiyang,Guizhou 550025,China;Research Institute of Chemical Defense,Beijing 100191,China)

机构地区：[1]贵州民族大学化学工程学院,贵州贵阳550025 [2]防化研究院,北京100191

出　　处：《电池》2024年第4期492-496,共5页Battery Bimonthly

摘　　要：过放电失效行为与电池的安全性能密切相关。为提升储能电站的安全性,对磷酸铁锂锂离子电池组(18并)开展研究。模组中如果有1只电池发生热失控,与之相邻的电池会因过放电导致电压均下降至0 V,体积鼓胀,但未发生热失控。X射线计算机断层扫描(XCT)测试结果表明,相邻电芯本体发生明显变形,呈现高低不平的状态,局部区域的极片分离严重,电芯顶部正、负极集流体出现一定的错位。拆解发现,负极两侧活性物质基本完全脱落,剥离后的铜箔局部区域有严重的“灼烧”点。SEM和能量色散谱结果显示:正极表面异常区域存在较高含量的铜元素,且表面覆盖有沉积物,主要为铜离子的堆积物;负极表面异常区域沉积物更明显,主要为锂盐的沉积物;隔膜异常区域表面存在大量的脱落电极材料,隔膜孔隙结构已被完全堵塞。The failure behavior with over-discharge is closely related to the safety performance of battery.In order to improve the safety of energy storage power stations,research on the lithium iron phosphate Li-ion batteries(18 parallel)is carried out.If a battery in the module is subjected to thermal runaway,the voltage of the adjacent batteries drops to 0 V due to over-discharge,the volume bulges,but no thermal runaway occurs.The result of X-ray computed tomography(XCT)test shows that the body of adjacent cell is obviously deformed,showing a state of unevenness,the electrodes in local areas are separated seriously,the cathode and anode fluid collectors at the top of the core are misplaced to some extent.It is found that the active substances on both sides of the anode electrode are basically completely shed,and serious"burning"spots appear in the local area of the stripped copper foil after disassembling.The results of SEM and energy dispersive X-ray spectroscopy show that there is a high content of copper in the abnormal area of the cathode electrode surface,and the surface is covered with deposits assignable to the accumulation of copper ions.The sediment in the abnormal area of the anode electrode surface is more obvious,which may be the sediment of lithium salt.There is also a large amount of sediment on the surface of the separator abnormal area,the separator pore structure has been completely blocked.

关 键 词：磷酸铁锂(LiFePO_(4)) 储能 锂离子电池 过放电 失效 变形 

分 类 号：TM912.9[电气工程—电力电子与电力传动]