加热策略对磷酸铁锂电池低温放电的影响

Effect of Heating Strategy on Low Temperature LiFePO_(4) Cell Discharge

磷酸铁锂电池具有安全性好和循环寿命长的优点,但在低温下,电性能差;本实验研究了低温-20℃环境中,在放电过程中采用不同的加热策略,对放电能量的影响,结果表明,随着放电倍率的增大,电芯的温升速率加快,放电能量提升;40 W功率加热不同时间,放电能量随时间增加而增加,减去加热膜消耗的能量,加热1 h净放电能量增加了11.26 Wh,加热2 h和3 h净放电能量没有提升。使用不同的加热功率测试,小功率长时间加热,对电池温度有良好的保温作用,可以提升内部化学反应速率和提高净放电能量,采用5 W功率加热8 h,净放电能量为707.52 Wh,提升了28.86 Wh。

Lithium iron phosphate battery has the advantages of good safety and long cycle life,but at low temperature,the electrical performance is diminished sharply;In this experiment,we analysis that at-20℃ambient temperature,the various of heating strategy effect on the discharge energy when cell is discharging.The result shows that as the discharge rate increased,the cell’s temperature rate has enhanced,and the discharge energy is increased.When 40 W power is External heating for different time,the discharge energy increases as time increased.Except the energy from heating film,the net discharge energy increased 11.26 Wh after 1h heating,while the net discharge energy no more increase after 2 h and 3 h heating.By different heating power test,low power and long time heating have a good heat reservation on the battery that can activate the internal chemical reaction rate and improve the net discharge energy,when using 5W power heating for 8h,the net discharge energy is 707.52 Wh,increased 28.86 Wh.