电压区间对LiFePO4/C电池循环性能衰减的影响

通过加速量热(ARC)、直流内阻(DCIR)测试及容量增量分析(ICA),研究IFR 32131型磷酸铁锂(LiFePO4)/C电池以1.00 C在2.00~3.65 V充放电时的热特性。电池在充电和放电末期,均出现温度快速上升的过程,且放电发热量较充电高出1 801.6 J;充放电的热功率拐点都出现在LiFePO4的准二元相变电压区间外,表明末期的快速温升为电池极化导致,且放电极化大于充电;放电DCIR比充电高。对比高区间(20%~100%)、中区间(10%~90%)和低区间(0~80%)等3种电压区间内电池80%放电深度(DOD)的循环性能,中区间电池的循环性能最好。

Effects of voltage range on cycle performance decay of LiFePO4/C battery

The thermal characteristics of IFR 32131 type lithium iron phosphate(LiFePO4)/C battery during charge-discharge process in 2.00-3.65 V were analyzed by accelerated calorimeter(ARC),direct current internal resistance(DCIR) test and capacity increment analysis(ICA).The process of rapid temperature rise occurred at the end of charge and discharge stage,the calorific value at the discharge stage was 1 801.6 J higher than that of the charge stage.The inflection point of the charge-discharge thermal power also occurred beyond the voltage range of pseudo-binary phase change of LiFePO4,indicating that the rapid temperature rise at the end was caused by battery polarization,the discharge polarization was greater than the charge polarization.The DCIR in the discharge process was higher than that in the charge process.The cycle performance of the battery cycled at 80% depth of discharge(DOD) in high voltage range(20%-100%),medium voltage range(10%-90%) and low voltage range(0-80%) under1.00 C was compared.The cycle performance of battery in medium voltage range was the best.