梯次利用磷酸铁锂方形电池过充火灾危险性研究

Preliminary study on fire risk of echelon use lithium iron phosphate square cell under overcharge

为了掌握梯次利用磷酸铁锂电池火灾的发生规律,采用不同过充方式和不同过充倍率对梯次利用磷酸铁锂方形电池(容量为25 Ah,SOH=80%)充电,考察在绝热条件下电池的燃烧爆炸特性。试验结果表明:当某型电池安全阀打开后停止过充,电池可能仅出现喷射烟气现象,不会发生火灾。当该型号电池安全阀打开后持续过充,充电倍率超过0.5 C时,梯次利用磷酸铁锂方形电池可能出现燃烧和爆炸。过充倍率的升高导致安全阀打开和电池出现温度和电压峰值的时间提前。

In order to master the occurrence and development law of echelon use lithium-ion battery fire,different overcharge methods and overcharge rates were used to charge the lithium iron phosphate square battery(25 Ah,SOH=80%)in echelon,and the combustion and explosion characteristics of the battery were investigated.The test results show that when the battery safety valve is opened and the overcharge is stopped,the battery may only discharge smoke and there will be no fire.When the battery is overcharged continuously after the safety valve is opened,the echelon use battery may burn and explode with the charging rate is more than 0.5 C.With the increase of overcharge rate,the opening of safety valve and the time to reach peak temperature and voltage will occur ahead of time.