商用Li_4Ti_5O_(12)电池倍率循环容量衰减模型

A capacity fading model for a commercial Li_4Ti_5O_(12) battery

Li_4Ti_5O_(12)(LTO)负极材料由于其优异的循环稳定性和安全性近年来得到广泛关注,并在电网储能领域具有巨大的应用前景,被视为下一代电网储能用负极材料。研究LTO电池的寿命模型有助于更好的设计能量存储单元,并推动LTO在储能领域中的应用。本文通过测试商用软包LTO基锂离子电池(标称容量10 A·h,额定电压2.2~3.5 V)在不同倍率下循环4800次的容量衰减,建立充放电倍率与容量衰减的对应关系。实验将每600次循环设为一个节点,通过在节点进行多电流密度标定从而实现分离电池的不可逆容量以及极化造成的容量损失。并利用试验数据,采用拟合、回归的分析方法,分别建立极化容量损失和不可逆容量损失两个电池衰减模型,该模型可用于预测LTO基电池剩余循环容量。

Li4Ti5O12 （LTO）-based battery has been considered as next generate energy storage battery for grid applications due to its excellent rate cyclic properties and cycle life. But up to now there is no capacity fading model which is suitable for LTO-based battery has been reported. We tested commercial LTO battery （nominal capacity of 10 A.h, 2.2-3.2 V rating）. The cells were tested at different rate for more than 4800 cycles, the irreversible capacity loss of battery was measured at 0.1 C to eliminate the polarization effect after each 600 cycles. The test data was then used to develop an empirical model by curve-fitting and regression techniques. It can be used to predict the rated capacity loss due to polarization and irrevisible capacity loss caused by loss of active lithium.