纯电动汽车用锂离子电池的低温性能

Low-temperature performance of Li-ion battery for pure electric vehicle

锂离子电池低温特性的研究多限于单体电池,且测试工况单一。分别以纯电动汽车用锂离子电池单体和系统为研究对象,设计以1/3 C放电至截止电压的恒流一次放电工况,以及以1/3 C恒流放电0.5 h,静置10.0 h,循环至截止电压的多天多次放电工况,并在0℃、-10℃和-20℃下进行放电测试。在多天多次放电工况下,电池单体和系统的放电容量分别为139.14 Ah、138.47 Ah,放电能量分别为505.98 W·h、44 443.40 W·h,均低于恒流一次放电工况下的相应数据;同一工况下,电池系统的低温放电容量低于单体电池。采用数据拟合方式,构建电池系统、单体低温放电能量与温度的关系公式。

The research on the low-temperature characteristics of Li-ion battery was limited to the cell,the test conditions were single.Taking the Li-ion battery system and cell for pure electric vehicles as the research object respectively,the galvanostatic once discharge conditions(discharge to cut-off voltage at 1/3 C)and the multi-day multi-times discharge conditions(1/3 C galvanostatic discharge for 0.5 h,resting for 10.0 h,cycling until the cut-off voltage was reached)were designed.The discharge tests were carried out at 0℃,-10℃and-20℃.The discharge capacity of Li-ion battery cells and systems under multi-day multi-times discharge conditions were 139.14 Ah and 138.47 Ah,the discharge energy was 505.98 W·h and 44443.40 W·h,respectively,which were both lower than the corresponding data under galvanostatic once discharge conditions.Under the same conditions,the low-temperature discharge capacity of the battery system was lower than that of the battery cell.The relationship equations between the lowtemperature discharge energy and temperature of the battery system and the single cell were constructed using data fitting.