锂离子电池放电—热滥用耦合热失控特性研究

Study on discharge-thermal abuse coupled thermal runaway characteristics of lithium-ion batteries

为了进一步揭示锂离子电池在使用过程中发生热失控的温度变化特性,对25 Ah方形硬壳磷酸铁锂电池进行不同放电倍率下的热失控对比研究,分别对相同电量的电池进行有、无放电电流,设置多组不同的电流大小进行物理实验。研究发现:不同倍率放电的动态过程下,电池热滥用行为的热失控现象与普通热失控不同,在0.5 C放电倍率下,90%剩余电量(以下简称SOC)的电池热失控最高温度超过了无放电行为的100%SOC电池。因此,在对于存在放电行为的电池进行热管理时,需进一步重视放电倍率对电池热失控温度的影响。

To further reveal the temperature variation characteristics of thermal runaway in lithium-ion batteries during their usage,a comparative study was conducted on the thermal runaway of 25 Ah square hard-shell lithium iron phosphate batteries under different discharge rates,and the physical experiments were carried out on the batteries with or without discharge current under the same electric quantity utilizing various sets of different current magnitudes.The results show that under the dynamic process of discharge with different rates,the thermal runaway phenomenon of battery thermal abuse behavior is different from that of ordinary thermal runaway.Under the discharge rate of 0.5 C,the maximum temperature of thermal runaway of the battery with 90%state of charge(hereinafter referring to as SOC)exceeds that of the 100%SOC battery without discharge behavior.Therefore,in the thermal management of batteries with discharge behavior,it is necessary to pay more attention to the influence of discharge rate on the thermal runaway temperature of batteries.